Joe is a great teacher and his instructions are easy to follow. After 1 lesson, I was able to grasp the general idea of lost wax casting, and now I found my new hobby. Thanks for everything Joe... - Feather
So awesome. Now I need all this stuff haha, I've been doing sand casting for awhile and never been really impressed with the details I can achieve. Can't wait to try this!!
Great vid! Have 22in swing arm spring loaded caster like yours, for years was just on a flat board with no sides, but when I started having issues throwing 8-10oz of molten bronze in an 8 foot diameter circle around my driveway I needed something better. Have to admit it never occured to me to build a wooden box around it. Wanted something fireproof... Friend was getting rid of an old stainless steel pool filter. The bottom part is on about a 12 inch base, which brings the whole thing up to a nice height to stand and do the balancing of the arm and melting/casting process. Mounted the caster in the bottom, it just fits inside the filter bottom. Welded a plate over the hole in one side where the pipe used to come in. Right up underneath the caster inside the base I bolted a brake drum from a flatbed tow truck, about 20-odd lbs of solid iron. Keeps the whole thing nicely on the ground, no tipping or even any wobbling. Very stable, and the steel is about 3 inches taller than the caster, so no more metal spills! Put the whole thing up on a wheeled board about 3 in tall and it lives under the workbench when not in use. Figured out my metal spill issue was that the arm is actually a little small for the big 4in wide 6in tall flasks I use though, so I made another weight for it by pressing one of the existing weights into some ordinary playground sand (damp, and let it dry out) and then pouring it full of bismuth. Actually weighs almost exactly the same as the cast metal weights the arm came with! Solved my balance problem with the heavier flasks. Just needed that one extra weight.
Pretty neat indeed. That centrifuge scared a couple years out of me and I'm 77 . I don't need any more hobbies, but this sure was interesting. Ken...Marina CA
Thank you for this video and answering all the questions. I took a class last weekend where we just carved and the instructor took home the wax to cast in his home studio. No overview of the process so his instructions made no sense to me. I will look on your website for classes to take because you explain things and seem to have given training techniques more than a little thought. It's a 3 hour drive for me but i am now thinking it is worth it. Thank you again!
Thank you! I'd love to help you learn all about casting. Our beginning class is a mix of wax work and casting, and students have the chance to sprue, invest and try their hand at casting. Hope you can attend a workshop with us. All the best, Joe
Wow! That's cool. Yes, casting has been around for 6000 years that we know of, starting with open face molds in ceramic and stone (which is still done today, for example with tufa stone castings as done by First Americans). Using lost wax casting (which started ascreating a model that can be removed by heat (was, plant materials, etc), enasing in clay, and burning it out in a fire) dates back to around 2300 BCE. It's so fantastic to know that we still use techniques today that were developed thousands of years ago. How amazing were those first artists?
Darn! that was a well presented instruction. Jut fascinating. Thanks very much. Too bad I went to Cal before you were in business, or I would have swept your floors to see it in person.
Thank you, that is such a clear and well paced video. Obviously you put thought and care into it. I do have one question. When you melt out the wax do you drain it from the bottom by inverting the flasks, or does the wax vaporise from the burn out in the kiln? A very noob question I know. But it is the only one I have in order to get a much more rounded understanding of the process. Thank you!
Larry McCauley Hi! Flasks are placed with the fill cup or mouth facing down for the wax to drain out. During the first stage of burn out, you can place the flasks on top of a wax tray. This tray allows the wax to drip into a metal pan for removal before the rest of the burn out happens. This cut down on smoke and odor. Flasks should go into the kiln raised on some kiln furniture so that the mouth of the flask is above the floor of the kiln, enough for the wax to drip out during burn out. Thanks for your question .
Very good , to the point without a bunch of useless filler. Question ❓ where do I find the non bubble stuff that you sprayed on the wax??? Is it simply a lite detergent and water mix? BTW I would love to attend your classes , but live near Atlanta Georgia far , far away from y'all
Hi Phil - Well, we do offer our classes online, too. Students attend through Zoom, from their home to our classroom, live with the instructor. :^) There are various brands of coatings you can use to help to prevent air bubbles from sticking to your models during investment. Here's one: www.riogrande.com/product/rio-vacu-film-concentrates/7021521gp Thanks for watching!
I'm assuming you'd normally have a lid for the centrifuge? I use this method and as soon as the metal is ready to go I put the lid on it and duck down behind the shield. On occation you can get some slag stuck in the feed hole or something else goes wrong and molten metal can go anywhere. Perhaps I'm over cautious?
I never see lost wax/ spin caster make air vents for displaced air, I've been having trouble casting an 18 gauge thin piece that folds over creating a thin arch the metal needs to get over...should I be using air vents?
HI! You can always try adding air vents to your models (just not all the way through the investment, because they metal could leak out during casting). I generally never use them with the centrifuge, myself. Thanks for watching!
Great video! Please tell me, what is that tiny hot pick-like (tiny soldering iron) looking tool you are using? It's awesome. Thank you for sharing your techniques.
That's an electric wax pen. They are awesome. I personally use an ARBE wax pen and a Foredom Wax Carver. The one shown is a Kerr wax pen. Thanks for watching!
bouth i guess... I put a drop (liquid dish soap for hand washing) in spray bottle, lets say a pee size, in a 400ml water. and with that i spray the model, with the same bottle i spray the mixing coup ( more for not leting as mush dust into the air) but it works for me. I suppose it has something to do with a water from the tap.
Great video, loads of useful tips. Thank you. Could you give me a rough idea of the total cost for all the big equipment needed. Vacuum table + centrifuge + kiln
No problem. Here's a kit for setting up to cast: www.ottofrei.com/Otto-Frei-Jewelry-Casting-Kit-2-Pro-110V. You'll also need a way to melt the metal, like a torch or a melting furnace.
In the video I recommended using a tumbler with mixed stainless steel shot to burnish the castings. The shot is covered with water with a drop of Dawn dish soap or similar. After casting, before polishing, I cleaned the castings by pickling them for 1 hour. The pickle solution I used is 1 part citric acid to 5 parts water, heated to steaming hot in a crock pot.
Very detailed video, I have two silly questions: 1. When you put the plastered flask in oven, why only the wax is melted but not the plaster? 2. Just curious, wouldn't the heated metal in the centrifuge spilled out when it's spinning? Thank you for the video again!
There are no silly questions. Just curiosity, which leads to learning. Here are your answers: 1. When you put the plastered flask in oven, why only the wax is melted but not the plaster? A: The kiln doesn't reach a temperature that would destroy the plaster. AND this is not just plaster we're using. It's investment. This is a special mix of plaster and other ingredients that can withstand high temperature. The wax melts out early, around 200-700 degrees. The higher temperature firing in the kiln does two things: it removes any residue of wax inside the investment mold, and it hardens the investment. 2. Just curious, wouldn't the heated metal in the centrifuge spilled out when it's spinning? A: You would think so, and sometimes if it's not properly set up or overfilled, some metal does spill out. But the crucible is designed to fit tight up against the invested flask, and is also designed to funnel the metal into the mold as it starts to spin. Not balancing the centrifuge or melting more metal than the crucible is rated for can cause metal to spill out the side. That's why it's inside of a box or well to contain any spills. Thanks for watching!
Thank you very much! Would there be any chance of you to upload a video about how a tennis bracelet is made? I am always curious how the parts are being connected together. Thank you again for answering my questions, you rock!
+Candace Quebe You can pour metal directly into the flask, but the problem is trapped air and gas that can cause the casting to be incomplete. One way around that is to add gates to the wax models when they're sprued, before the investment is poured. Gates are vents that lead away from the model towards the opposite end away from the pour, but not necessarily completely out of the plaster mold. They give the gas and air places to get trapped away from the model you made. The jewelry industry uses vacuum assisted pour casting to increase the rate of success. The flask is prepared with a special webbing that burns out along with the wax models and/or flasks that are made for vacuum casting. When it's time to pour, the flask is placed on a silicon pad with an opening connected to a vacuum pump. The vacuum pulls air and gas from the mold as the molten metal fills it. When you compare the delivery of metal from the crucible between centrifugal casting and vacuum casting, one thing to consider is how effective is the delivery of molten metal into the flask. When you pour metal into the flask, it's slow and if the pour is stuttered or falters, can create cracks or faults in the casting. A centrifuge snaps the metal into the mold quickly and holds it with the force of the centrifuge as it cools. Can you be successful with vacuum assisted casting? Absolutely. Is it better than the centrifuge? For some things, like big flasks with thick castings. The centrifuge is excellent for detailed castings. Whichever method you choose, with practice it can handle most of your casting needs. Thanks for the question. Joe
Quick question. I’m a pretty good mold maker but just starting my research into metal casting. Do I need to use wax to create the investment mold? I feel I can create the investment mold by creating A silicone positive of my object that the investment can be poured around, than removes pretty easily. If the wax step could be skipped it would save so much time and effort. But I’m sure I’m missing something because I can’t find the answer to the question anywhere. My object “a slightly tweaked rubber duck” is just complicated enough to rule out other casting methods. Thanks in advance for you time, your videos helped me a lot.
Hi Jamie - You can make an RTV mold of a wax model or other objects that you can inject with wax, and then invest it and cast it, but you can't cast non-ferrous metals like silver and gold into a rubber or silicone mold. The metal is too hot and will burn the mold. You can cast using a moldable object using a sand casting method, which doesn't use investment. Low temp metals, like pewter, can be cast in vulcanized rubber molds. Hope this helps. Thanks for watching! Joe
No idea if anyone will see this now but worth a shot! Just wondering at what stage you make the rubber moulds for re-use? And if theres any good videos you reccomend to do this? Also any suggestions on where to source metals for casting e.g. gold. Thanks!!
Hi Caitlin - The first investment mold, which is shown in this video, is destroyed at the end of the process. After the cast pieces are polished, they're molded in natrual rubber or RTV silicone. These are injected with wax to create exact copies of the original and the process starts again. Wax models go into the flasks, etc. As far as videos... I recommend our online classes! If this is something you'd like to learn, check out our online classes at www.silverajewelry.com/classes/default.asp?typeFilter=online. We have a whole series of classes on lost wax casting and wax carving, teaching you all you need to know from a-z, including Lost Wax 2, which covers making molds and casting found objects. They're live on zoom and recordings of our class together are available to watch again afterwards. Thanks for watching!
@@joesilvera8853 Thank you so much for your detailed reply! I'm definitely going to look into those classes- hopefully starting an exciting new journey!
Hi - Thanks for your question. I'm guessing you mean the Vac-u-coat spray that I used before investing? This is a standard step to help prevent air bubbles from sticking to your models. It is sold under different names, like Vac-U=Coat from ProCraft and Vacufilm from Rio Grande. You can find it here: www.riogrande.com/product/rio-vacu-film-concentrates/7021521gp Best and thanks for watching, Joe Silvera
Hi I’ve seen a ton of the bases you attached your sprue tree to have a hole in the area you attach the sprue to. Yours doesn’t have that. I’m worried the metal will go straight out that hole in my investment if that makes sense. Have you seen the bases I’m mentioning?
Hi Matt - There are two reasons a rubber button former base will have a hole, in my experience. 1) it's a hole to fit a large main sprue wax rod (this is a partial hole at the top of the button former), 2) a hole in the base and no rubber button former (this is to screw in a NeuTec style main sprue that includes the button shape. www.riogrande.com/knowledge-hub/articles/why-use-the-neusprue-sprue-and-base-system/ Thanks for watching!
Very good videos. Very informative. Do you take jobs in for pay. I just am asking because I would like to make a drive sprocket in metal the size of a quarter but I am not that good in making molds.
Hi - Thanks for watching and for your question. I'm teaching jewelry a 110% of my time, so no jobs at this time. However, you can find a list of casters on our site: www.silverajewelry.com/links.asp?cat=13
Wow, this is actually a really nice video about lost wax casting! I have one question though: you've used a centrifuge for casting. Why is that? Couldn't just pouring the metal (silver?) into the plaster mold produce the same result?
Hi and thanks for your question. In order to fill the mold completely the molten metal requires the help of force to overcome the resistance of gas and air pockets in the mold. A centrifuge applies force that easily overcomes that resistance. Just pouring the metal usually results in incomplete castings. Another common method is a vacuum assisted pour. The steel flask is placed on a vacuum table, and when sealed the vacuum draws air out of the mold, lowering the atmospheric pressure inside the flask. This lower pressure provides the force to help the molten metal fill the mold completely. Thanks again! Joe
I see. Thanks! So does this happen because of the small size of the castings and the molten metals' surface tension? Also, what's the size above which this stops being a problem?
Well, I know from when I did foundry (sculpture size) castings in college that we did not assist the casting with a vacuum, etc. We just poured. The mass of the metal and the construction of the sprues and models was enough to get a successful casting. Jewelry flasks are usually smaller than 4x8 inches and at that size, some sort of additional force is used. I don't know specifically where between jewelry and sculpture additional force is no longer needed. It's a good question! But since I only do jewelry casting, it's outside my expertise. Let me know if you find out.
Actually now that you've mentioned I've realized that you haven't used any sprues for the casting, which probably also makes a big difference. But yeah, it pretty much looks like I'll have to learn about the limits the hard way. Thanks anyway!
Even at this small scale, we use sprues and gates. The terminology can be swapped, but in the video you'll see sprues connecting the models to the button or fill cup. And they're there in the metal casting at the end. What you often don't see in centrifugal casting of jewelry are vents, or small sprues running away from the top of the models to release trapped gasses away from your work. With a good set up and proper casting, they're generally unnecessary.
I don't have it anymore, but it was basically a few inches larger on each side of the centrifuge arms when fully extended. You can also find pre-made metal casting wells for centrifugal casting machines. Make sure the height and width are larger than your machine.
Hi Betty - Thanks for your comment and for watching! :^) Sometimes a little metal gets past the crucible, but the spinning sends it downwards to the bottom of the box where it sizzles and puts itself out quickly. I've heard of rare failures where the crucible comes loose, but this is usually because of a failure to make sure that either the crucible is correctly put into the cradle or using a wrong size crucible that isn't compatible with your machine. The walls of the box help to keep any spray contained, and you can use safety gear, like a face shield. It's a good question, but in 25 plus years of casting I've never had more than a few drops of metal spray into the box during any casting. The key is to balance the machine before each casting, balancing the weight of the crucible, metal and flask against the adjustable weights on the other end of the machine. Thanks again, Joe
Hi Michael - Thanks for your comment. I didn't build the centrifuge, just to be clear. That is a machine I purchased almost 20 years ago - wow! Time flies. I built the box to hold it, and put it on casters so I could move it around. Thanks again, Joe
The kind of 3D printing that would make silver printing viable (FDM) will never produce a finish as smooth and flawless as this process. You'll always see the "artifacts" in the printed object, no matter how small they are.
I agree... for now. But as the technology improves, those flaws may be harder to detect or simply just solved in the finishing process. I used to be able to tell 3D printed or CAD work from hand carved, but the programs for creation and the users have become so sophisticated that you can actually replicate some of the wabi-sabi "flaws" of the human hand now. In other words, give it more soul. I've seen computer printed models that were hard to tell that they were made by a machine. The future is coming, and it's looking more like the world of Start Trek every day. :^)
I'm actually doing casting right now with aluminum and silicone. If you use something like ABS you can do a smoothing process with acetone vapors. When the print resolution is high enough, combined with casting, you really can't tell. It at least allows you to more fine tune the model virtually before casting.
Hi - Good question. Yes. Any mixing will add air to the mix, even by hand. That's why we use the vacuum investment table to pull air bubbles out of the investment. Thanks
Not at this time, Jean, but when I do I'll announce it on my RUclips channel so please subscribe. Or you can sign up for our email list at SilveraJewelrySchool.com/lists. We do offer workshops at our school in Berkeley, Ca. Thanks! Joe
Interesting how experience saves you so much time and effort. I mix my investment in a plastic bowl with a wooden spoon. I know how thick it has to be and roughly how much I need, so I do it by eye. I then tap out the bubbles using a piece of wood, saving me the expense of a vibration or vaccuum machine. I also paint my waxes with investment before this process so bubbles won't stick to it.. When it comes to the burn out cycle, again, all this waiting for hours is unnessessary. Once my investment has hardened in the flask, I leave it about 15 minutes and put it in a cold kiln set to 149c degrees for dewaxing. I put a tray undernieth to catch the wax so it doesn't screw up the kiln. After about half an hour at that temp I remove the tray with the melted wax and ramp it up to 371c degrees. You hear all sorts of bubbling sounds initially but it soon calms down and you get steam coming out of your inspection hole in the door of the kiln. You wait about half an hour until most of the moisture has evaporated and the jet of steam subsides, I then ramp it up to 732c degrees, leave it for 1.30 hours and its ready to cast. I've got this 8 hour burn out cycle down to 2 1/2 hours and you don't have to leave you're flask overnight to dry.. I preheat my bronze and take the still red hot flask out of the kiln at about 600 degrees. I believe it loses about 100 degrees a minute so you have to get it in the cradle and melt your bronze as quick as you can. I use borax to help the bronze flow and know through experience when its liquid before I let it spin. Overheating it causes the metal to separate so you have to get it just right. I enjoy 100% success as long as my sprues are well placed.. Whatever methods you use to save time, safety has to be at the forefront of your mind. You can do hundreds of castings but it only takes one mechanical breakdown to send molten bronze at 1100F flying around the room. You always have to be safely behind a screen just in case and never let animals or anything else distract you.
Thanks for sharing your process! Very interesting. There's always a different way to cast, and I can see from your description that you've carefully experimented with your set up to produce reliable results. I just want to note that the processes shown in my video are in line with manufacturers's guidelines for investment and burnout, and are based on their research for best results . Happy casting!
Great video, but I have one question when you put the flask in the crucible is it warm,cold or how should it be? because I trie to make my first casting with a centrifuge and what happened was the metal pierced the plaster leaving the mold empty, so also what would you recommend me to de next time? Thank you
Hi - The flask should be warm, a few hundred degrees below casting temperature or around 950-1000 for fine castings, 900 degrees for thick castings. Make sure when you invest your models that they are not within 1/4" of the sides of the flask and that they're 1/2" below the top of the flask. Too close to the sides and top and the metal can break through. Happy casting!
Hi - The system you use will determine how big your flask can be. Centrifuges and vacuum casting machines have maximum flask sizes. If you want to cast something larger, you'll need to source a way of helping the casting with enough force to fill it without getting incomplete castings due to air or gas pockets.
Craig Murray There are casting systems like Neutec from Rio Grande that can handle flasks up to 6x10 inches. Here’s a list of casters on our site: www.silverajewelry.com/links.asp
Very cool video. This is the first time I've seen a centrifugal casting device. When the wax gets melted out, do you collect it for reuse? It would seem rather wasteful to just burn it all. Is the investment a dangerous material? I'm guessing it's not plaster of Paris and may contain silica? I would love to have a go at this myself.
Hi - Thanks for watching. You have the option to steam out wax before burnout if you're using lower temperature injection waxes. Carving waxes are harder to steam out. But it's usually mixed with the sprue wax and water and not usable, But steaming it out makes the burnout cleaner with less odor and fumes. We use a specialty investment for casting that is similar to plaster but has ingredients to make it better for high temp burnout. You do have to be careful whenever using investment. I wear a respirator. Thanks again, Joe
What is that tool your using to put the wax on, the one your dipping into the hard wax....I've been teaching myself how to do this stuff but one if the hardest things to learn about are all the tools, no internet searches I've used are any good. I've seen something that looks like it even lays wax ( not a batik pen) but cant find it anywhere. I have a lot of questions, but never receive answers.
Hi Hex! It's a wax pen. That model is a Kerr wax worker, but you can find inexpensive wax pens from battery powered SuperMax pens, and electric Foredom Wax Carvers or the Arbe Wax pen. They're great for welding cracks, build up and lots more! We cover wax pens and lots more in our Lost Wax 1 - Basics workshop, which is also available live online. SilveraJewelry.com/classes
@@SilveraJewelrySchool every time I entered searches for wax pens I got wax carvers only, I've got one of those 2 arm dental heat deals ..but an Arbe wax pen? I'll look it up, something that I've seen but haven't been able to replicate was the laying down of hot wax onto a mold, making patterns or frames that then come right off. Even with mold release hot wax sticks, and its too liquidy, but the wax pen I saw was laying a thick line, like you'd expect from Elmer's glue. I'll check out that episode that covers them as well thanks!
You could make a model out of anything that burns out cleanly, even candle wax. But we use waxes developed for jewelry that are better to work with and can even be sawn, filed and sanded. Check out the waxes at www.silverajewelry.com/store/w/c/355/t/Waxes/browse.asp Thanks for watching!
Hi Baz - I'm using a rotary rock tumbler. It's loaded with 2 pounds of mixed shapes of stainless steel shot. To lubricate the tumbling, I use enough water to just cover the surface of the shot, and a drop of tumbling compound, like ShineBrite, or a drop of Dawn blue degreasing liquid dish soap. This kind of soap is the cleanest with the least additives for tumbling, or for cleaning your metal. So something similar to that would work fine. Just a drop! Too much and the suds are insane. Happy tumbling and thanks for watching! - Joe Silvera
Thank you for the informative reply :) May I also ask if using a tumbler would work to burnish aluminium parts? I'm currently sanding craft items and then polishing them, this would be a welcome alternative.
Hi - I use Kerr Satin 20 investment, which is different from regular plaster. It's formulated for the intense heat and duration of a casting burnouts. Good question about pouring. If you pour metal into the investment mold you are likely to get voids in the casting from trapped air or gas. But if you either use a centrifuge or do a vacuum assisted pour, you can get great results. Thanks for watching!
OttoFrei.com sells a good casting kit including a kiln and centrifugal casting machine: www.ottofrei.com/Otto-Frei-Jewelry-Casting-Kit-2-Pro-110V. That will give you a basic list of parts for casting. You will need a casting torch (oxygen/propane is best) or an electro melt furnace to melt the metal. The torch works best for both vacuum casting and the centrifuge. Thanks for watching!
Silvera Jewelry School Thank you for this educational video. I did have a question I was hoping you could answer for me. The plaster you use. Is it a special blend mix or it plaster of Paris? Just curious because I have seen other videos where the mold has to be broken open versus disintegrating in water. Thank you :D
Hi - Thanks for watching. Special investment is recommended for jewelry casting, not plaster that you would use for sculpture, etc. Casting investment is mixed with materials that allow it to be fired at temps upwards of 1300°, to receive molten metal that is hotter than that, and to have very fine detail for the best casting. Some investments are formulated for purging in water, or to be more receptive to being removed by breaking the investment. For example, investment formulated for casting stones in place needs to be removed when the mold is cold, so it's made to break up easily. Most investments will remove fairly easily by breaking the investment mold after casting, even just by rapping the steel flask with a mallet, especially if the flasks are small. Best, Joe
I'm a little late to this video, but it's a great demo! Can I ask - I have the same kiln (just got it). What is your burnout temp schedule for it? I've yet to use it, and haven't figured out how best to use it compared to my homemade one I used to use (talk about a guessing game!). Any suggestions? Do you ever steam the wax out first? That's what I used to have to do with my homemade kiln, but my understanding was that with this kiln I don't have to. Thanks! Great video!
+kathleen connor Hi Kathleen - I use Kerr Satin Cast 20 and they have a great PDF at The art and science of lost wax casting. - Kerr Casting that includes mixing instructions and sample burnout schedules. You can use the sample schedules to program your kiln. A steam de-waxer is on my wish list, but I don't have one yet. Steam de waxing is usually optional. It's a way to decrease smoke and odor during burnout. A burnout kiln should have a hole in the top to release the smoke.
I want to make make a silver belt buckle. I got kiln to do the lost wax brun out. I got a oxygen/kerosene tourch, and made me top vaccum. Here is my question.: Hiw do I know that the solver is hot enough to Puerto it into the mold?
Hi - The silver will melt into a smooth rounded puddle. The surface will look like a mirror and can also appear to move and roll. If you're melting in a crucible with a handle you can gently swirl the liquid metal in the crucible to be sure that there are no solids left. Don't let the metal boil - it will look like the surface is quivering and jumping. Good luck and be safe. Be sure to wear tinted glasses to avoid getting cataracts from repeated exposure to infrared light from the hot metal and UV rays from the torch.
I have seen some videos that teaches to set various temperatures program on the kiln. Do I have to do that way or can I go up to the 1350f and then down to 1000f?
Isa Abd Rahman Sosa-Dominguez Hi -it’s best to run your kiln through a number of stages, slowly ramping your temperature up to the maximum, and then slowly dropping it down to casting temperature. Sample burn out kiln programs are offered by the manufacturers of the casting investment on their websites. Best, Joe
Just wondering what made you tumble the cast pieces before doing the end finishing instead of tumbling at the end? Also I was just wondering how long you usually tumble your pieces for?
+Adam Lagace Hi. Thanks for watching my video. - Tumbling is an option for a final finish. First I cut off the sprues, grind and clean the nubs left by the sprues and blend those areas back into the rest of the finish. Then I touch up any flaws up to about 400-600 grit finish. Finally, I tumble in stainless steel shot or with fine steel pins for up to 2 hours to burnish the metal to a high luster. Burnishing has the advantage of not removing any additional metal and also closing any fine pits or porosity. Hand finishing and polishing with abrasives can reveal any fire stain from casting, and may require removing more of your carved details. Burnishing can polish the fine silver loam from pickling after casting and preserve your carving. Best, Joe
Great video, thanks for posting! I'm looking to cast a 2" puck of gold, and we're looking to use a lost wax method. The final part will be ~1mm thick by 2". Do you have any suggestions on casting something like this without a centrifuge? We have a vacuum oven (which was how I was planning on baking out the wax) and I was thinking that we might get away with some small vents at the edge of the puck if we set the investment into the vacuum oven when we pour it. If you see anything egregious about that method, please stop me before I waste a lot of time :)
HI - Thanks for watching and your question. If you have trouble filling the entire 2" diameter 1mm sheet, the model may be too thin. You may need to up it to 1.3mm (16 gauge). Good luck with your casting. Joe
Hi! The exact method to loosen the arm for balancing may vary. Read any instructions that came with your centrifuge. But basically you release the arm so that it can move like a balance. Load the flask in the cradle, the crucible and the metal weighed for casting. Move the weights on the other and add or subtract weights until the arm is balanced. Thanks for watching!
@@SilveraJewelrySchool Thank you for the clear explanation! I started silversmithing in 1969 but had to quit about 9 years later because I couldn't have little kids running around the flames, etc. I just started doing custom leather instead. But, I still have my bench, tools and equipment and am setting it all up again..The instructions that came with my centrifugal casting machine are long gone by now so I am thankful you answered my question and reminded me! Your video has such a clear explanation. Thank you so much!
+pikkilo Getting a good casting is about force: getting more than the force of gravity applied to the molten metal so that it fills the mold. Vacuum assisted casting lowers the atmospheric pressure in the mold and forces the metal into the recesses. New vacuum machines are better than they used to be, but a centrifuge has even more force applied to the metal for more reliable casting. Also, the centrifuge takes care of fast and accurate delivery of the molten metal to the models. Vacuum assisted casts still depend on a person to pour the metal (unless you have a thousands of dollars for an industrial model). If you stutter the pour or mess up, oops, bad casting. I've always preferred a centrifuge over vacuum casting.
I'd suggest taking a class to learn how to use the equipment. We offer online casting classes with instruction on how to make wax models and how to cast. SilveraJewelrySchool.com/classes. Casting kits are for sale at RioGrande.com and OttoFrei.com
Hi Jorge - Thanks for your comment. Yup, this video is on the casting process, so it picks up after the models are complete. Making wax models is a whole process in itself and the focus of our classes here at Silvera Jewelry School. But we use this video as well as live demonstrations to illustrate the lost wax process. Best, Joe
Hi KC - I'm guessing that you mean the investment that I mixed with water for the mold. It's casting investment. You can buy it from jewelry suppliers. It looks like simple plaster but is not the same, since it has to be fired to high temperature in the kiln. Thanks for watching!
Making a rubber mold from a wax model is an alternative. Just to be clear, you can't cast precious metals or base metals into a rubber mold. Only low temp metals like pewter, etc. I don't use borax. I use boric acid. It's a higher temp an is commonly used for casting jewelry and ingots. It's a short video, not a tutorial. Can't put everything in there. :^) Thanks for watching!
Hi - Thanks for your question. Since there's more to it than temperature for the burnout, here's a link to a PDF from Satin Cast 20 investment re: burnout schedules and temperatures. romanoff.com/media/pdf/76-106-NY.pdf All the best and thanks for watching. Joe
I did this in college. I still don't know why it's called "lost" wax casting. It's removed... but that still makes no sense. In fact, the plaster is "lost" too, so...?
The name is focused on the wax. It's melted out during the burnout and replaced with metal during casting. It may be a carry over from other languages, like "cire perdue" in French. With 7000 years of metalsmithing history, a lot of names are passed down. It wasn't alway investment for the mold. Ceramic (clay molds like in Ashanti casting), sand, etc have been used, too, some of which could be reused a couple of times. Thanks for watching!
I just brought the same neycraft oven what setting do you use for the wax burnout? Does it ramp up and hold its self or do you have to manually adjust it your self?
@@deeaikens9843 Sorry I just saw your reply. You need to set the Neycraft manually. It doesn't have a controller. So keep notes for dial positions. Or you can buy a separate kiln minder that you can program like this one that will hold a lot of programs for burnout, etc. www.riogrande.com/product/kilnminder-oven-controller-k4e/703094
What temp do you use to cure the investment and what temp do you use to burn out the wax? I’m afraid to do these wax models because they took a lot of time to make
@@deeaikens9843 Hi - So you let the investment harden at room temperature for 2 hours after investing. The kiln program for the burnout varies according to the size and number of flasks you're burning out. The investment manufacturers offer free pdfs with instructions on burnout schedules/temps and investing. Like this one: docs.wixstatic.com/ugd/cc5f22_c4ac76d773c94aa5b8ceff61af77b72f.pdf Best of luck with your project! Joe
ebaymaster You can make a model out of anything that meets the specs to burn out in the kiln cleanly. Jewelry waxes don't leave a lot of soot and mess to deal with, so I would recommend using carving or build up wax from a jewelry supplier. Sculptors (as in foundry casting) use paraffin wax that is more similar to bees wax. That could be used too and you may be able to find it at an art supply.
Hi - I use Kerr Satin 20 investment, which is different from regular plaster. It's formulated for the intense heat and duration of a casting burnouts. Thanks for watching!
Your work is wonderful and is like our work a lot, I have a question Can I find a job in the field of the Rings industry in America or Europe, and how do 💍💎💍💎💍
Hi Youcef - Thanks! Appreciate it. Getting into the jewelry industry in America and Europe takes time and a good portfolio of jewelry that demonstrates your skills. And patience while you contact jewelers for opportunities to work. If you can get certified by taking the tests at jewelers.org www.jewelers.org/ja/careers-education/certification. Good luck! Joe
+Candace Quebe It's best to buy it. A centrifuge is built around a powerful spring, which should only be serviced by a professional. In the 20+ years I've had my centrifuge, it's never had to be serviced. You can buy it from a jewelry supplier, like RioGrande.com, or OttoFrei.com. Make sure you get some training on safe use of a centrifuge, just as you would with a vacuum assisted casting machine. We offer casting workshops at Silvera Jewelry School, our school in Berkeley, CA. But there are lots of good jewelry schools all over the US now. Best! Joe
+Silvera Jewelry School Thank you very much for your help, I have one more question is there anything cheaper than investment plaster something that I can get by with? I would like to test out casting before I get this expensive plaster.
+Candace Quebe Hi again! I would recommend just buying a small amount of the correct investment plaster. Using the wrong kind can skew your results and be disappointing.
+Candace Quebe I use two kinds: an acetylene torch (it draws it's own oxygen, so single acetylene tank). or a oxygen and propane casting torch. If you're casting a small amount, like less than 2 ounces, and especially if you can preheat your crucible in the kiln at the end of the burnout, you may be able to get away with a plumbers torch from the hardware store: propane or mapp gas, until you're ready to invest in a better torch.
I appreciate your comment. It’s true that these machines are set into casting wells with lids, which I also recommend to students setting up a new system. I can also let you know that I have used centrifuges for casting for thirty years and have never been injured, even without a lid. What’s important to understand is the physics of a centrifuge causes any spills to move in the same plane as the machine. So metal will hit the walls inside the well, and it will not fly up and out of the box. As a casting teacher I’m way more concerned about student injuries when they’re working with open crucibles of molten metals for pouring into flasks. The rules for safely using a centrifuge are simple and these machines offer s lot of reliability and accuracy. Thanks again.
this is probably one of the best videos i have seen regarding the process for sure
Great video there, helped me learn the age old technique that is still in use in the modern world
Joe is a great teacher and his instructions are easy to follow. After 1 lesson, I was able to grasp the general idea of lost wax casting, and now I found my new hobby. Thanks for everything Joe... - Feather
this is a really bloody decently done video simple and straight forward i now think i can attempt lost wax casting now
Thanks!
So awesome. Now I need all this stuff haha, I've been doing sand casting for awhile and never been really impressed with the details I can achieve. Can't wait to try this!!
Very nice to watch a video done in under 10 minutes that many would have done in an hour! Thanks!
Great vid! Have 22in swing arm spring loaded caster like yours, for years was just on a flat board with no sides, but when I started having issues throwing 8-10oz of molten bronze in an 8 foot diameter circle around my driveway I needed something better. Have to admit it never occured to me to build a wooden box around it. Wanted something fireproof... Friend was getting rid of an old stainless steel pool filter. The bottom part is on about a 12 inch base, which brings the whole thing up to a nice height to stand and do the balancing of the arm and melting/casting process. Mounted the caster in the bottom, it just fits inside the filter bottom. Welded a plate over the hole in one side where the pipe used to come in. Right up underneath the caster inside the base I bolted a brake drum from a flatbed tow truck, about 20-odd lbs of solid iron. Keeps the whole thing nicely on the ground, no tipping or even any wobbling. Very stable, and the steel is about 3 inches taller than the caster, so no more metal spills! Put the whole thing up on a wheeled board about 3 in tall and it lives under the workbench when not in use. Figured out my metal spill issue was that the arm is actually a little small for the big 4in wide 6in tall flasks I use though, so I made another weight for it by pressing one of the existing weights into some ordinary playground sand (damp, and let it dry out) and then pouring it full of bismuth. Actually weighs almost exactly the same as the cast metal weights the arm came with! Solved my balance problem with the heavier flasks. Just needed that one extra weight.
It pays to be handy when it comes to problem solving your set up for equipment, especially casting stuff. Thanks for sharing your solution!
Pretty neat indeed. That centrifuge scared a couple years out of me and I'm 77 . I don't need any more hobbies, but this sure was interesting. Ken...Marina CA
Kenneth Bartlett Thanks! The centrifuge is a pretty exciting but reliable way to cast.
Thank you for sharing your knowledge
A most excellent tutorial, Thank you for sharing.
Thank you for this video and answering all the questions. I took a class last weekend where we just carved and the instructor took home the wax to cast in his home studio. No overview of the process so his instructions made no sense to me. I will look on your website for classes to take because you explain things and seem to have given training techniques more than a little thought. It's a 3 hour drive for me but i am now thinking it is worth it. Thank you again!
Thank you! I'd love to help you learn all about casting. Our beginning class is a mix of wax work and casting, and students have the chance to sprue, invest and try their hand at casting. Hope you can attend a workshop with us. All the best, Joe
This video is recommended in my art book, we're studying the iron age in Ireland and they used this technique very cool to see!
Wow! That's cool. Yes, casting has been around for 6000 years that we know of, starting with open face molds in ceramic and stone (which is still done today, for example with tufa stone castings as done by First Americans). Using lost wax casting (which started ascreating a model that can be removed by heat (was, plant materials, etc), enasing in clay, and burning it out in a fire) dates back to around 2300 BCE. It's so fantastic to know that we still use techniques today that were developed thousands of years ago. How amazing were those first artists?
Very clear and interesting video ! Thanks a bunch!
Thanks! :^)
You are a really good teacher.
Thanks!
wow! beautiful presentation! well done!
+Gil Raz Thank you!
Back for another visit and a few more I am sure. I am getting setup to do larger pcs. 1 to 5 ozt but well done showing process. Thank you !
Nice video been interested in casting its the final piece of the puzzle for my shop.
Darn! that was a well presented instruction. Jut fascinating. Thanks very much. Too bad I went to Cal before you were in business, or I would have swept your floors to see it in person.
Excellent video.
I have 2 questions.
Why does burn out take so long?
Can you use a conventional oven?
thank you for this very instructive video
Thank you for the "insights" into your craft.. (art). I had no idea :O)
Thank you, that is such a clear and well paced video. Obviously you put thought and care into it.
I do have one question. When you melt out the wax do you drain it from the bottom by inverting the flasks, or does the wax vaporise from the burn out in the kiln?
A very noob question I know. But it is the only one I have in order to get a much more rounded understanding of the process.
Thank you!
Larry McCauley Hi! Flasks are placed with the fill cup or mouth facing down for the wax to drain out. During the first stage of burn out, you can place the flasks on top of a wax tray. This tray allows the wax to drip into a metal pan for removal before the rest of the burn out happens. This cut down on smoke and odor. Flasks should go into the kiln raised on some kiln furniture so that the mouth of the flask is above the floor of the kiln, enough for the wax to drip out during burn out. Thanks for your question .
@@joesilvera8853 Thank you so much for you informed and helpful reply.
Very good , to the point without a bunch of useless filler. Question ❓ where do I find the non bubble stuff that you sprayed on the wax??? Is it simply a lite detergent and water mix? BTW I would love to attend your classes , but live near Atlanta Georgia far , far away from y'all
Hi Phil - Well, we do offer our classes online, too. Students attend through Zoom, from their home to our classroom, live with the instructor. :^) There are various brands of coatings you can use to help to prevent air bubbles from sticking to your models during investment. Here's one: www.riogrande.com/product/rio-vacu-film-concentrates/7021521gp Thanks for watching!
great video, thanks for sharing, do you offer 1 on 1 tutorial ?
We do now! Check out our online lost wax casting class for a start www.silverajewelry.com/classes/w/ID/538/eventID/4253/details.asp
Great Video and summary! Thanks for sharing.
Would you say the machine that vacuums out all the air bubbles was... a good investment?
Nice!
I'm assuming you'd normally have a lid for the centrifuge? I use this method and as soon as the metal is ready to go I put the lid on it and duck down behind the shield. On occation you can get some slag stuck in the feed hole or something else goes wrong and molten metal can go anywhere. Perhaps I'm over cautious?
I never see lost wax/ spin caster make air vents for displaced air, I've been having trouble casting an 18 gauge thin piece that folds over creating a thin arch the metal needs to get over...should I be using air vents?
HI! You can always try adding air vents to your models (just not all the way through the investment, because they metal could leak out during casting). I generally never use them with the centrifuge, myself. Thanks for watching!
Great video! Please tell me, what is that tiny hot pick-like (tiny soldering iron) looking tool you are using? It's awesome. Thank you for sharing your techniques.
That's an electric wax pen. They are awesome. I personally use an ARBE wax pen and a Foredom Wax Carver. The one shown is a Kerr wax pen. Thanks for watching!
i like using a ultra small drop of dish soap in the mix. the bubbles and lumps are diminished drastically.
Do you add the drop of dish soap to the investment mix or the debublizer mix?
bouth i guess... I put a drop (liquid dish soap for hand washing) in spray bottle, lets say a pee size, in a 400ml water. and with that i spray the model, with the same bottle i spray the mixing coup ( more for not leting as mush dust into the air) but it works for me. I suppose it has something to do with a water from the tap.
Great video, loads of useful tips. Thank you. Could you give me a rough idea of the total cost for all the big equipment needed. Vacuum table + centrifuge + kiln
No problem. Here's a kit for setting up to cast: www.ottofrei.com/Otto-Frei-Jewelry-Casting-Kit-2-Pro-110V. You'll also need a way to melt the metal, like a torch or a melting furnace.
@@SilveraJewelrySchool perfect thank you. I can see why it’s normally just the professionals that can justify the expense.
What kind of liquid u use after casting to clean rings tell us plz
In the video I recommended using a tumbler with mixed stainless steel shot to burnish the castings. The shot is covered with water with a drop of Dawn dish soap or similar. After casting, before polishing, I cleaned the castings by pickling them for 1 hour. The pickle solution I used is 1 part citric acid to 5 parts water, heated to steaming hot in a crock pot.
hello, could you please tell me the solution you sprayed on the wax to prevent bubbles to stick? thanks!
Sure! I use Vac-U-Coat. www.ottofrei.com/Pro-Craft-VAC-U-COAT-7-1-2-oz-with-Spray-Pump
Very detailed video, I have two silly questions:
1. When you put the plastered flask in oven, why only the wax is melted but not the plaster?
2. Just curious, wouldn't the heated metal in the centrifuge spilled out when it's spinning?
Thank you for the video again!
There are no silly questions. Just curiosity, which leads to learning. Here are your answers:
1. When you put the plastered flask in oven, why only the wax is melted but not the plaster?
A: The kiln doesn't reach a temperature that would destroy the plaster. AND this is not just plaster we're using. It's investment. This is a special mix of plaster and other ingredients that can withstand high temperature. The wax melts out early, around 200-700 degrees. The higher temperature firing in the kiln does two things: it removes any residue of wax inside the investment mold, and it hardens the investment.
2. Just curious, wouldn't the heated metal in the centrifuge spilled out when it's spinning?
A: You would think so, and sometimes if it's not properly set up or overfilled, some metal does spill out. But the crucible is designed to fit tight up against the invested flask, and is also designed to funnel the metal into the mold as it starts to spin. Not balancing the centrifuge or melting more metal than the crucible is rated for can cause metal to spill out the side. That's why it's inside of a box or well to contain any spills.
Thanks for watching!
Thank you very much!
Would there be any chance of you to upload a video about how a tennis bracelet is made? I am always curious how the parts are being connected together.
Thank you again for answering my questions, you rock!
No, sorry. Tennis bracelets aren't my thing. But if you search around hopefully you'll find something helpful.
Do you need a centrifuge to transfer the molten metal to the flask casting? Can you just pour the molten metal into the flask?
+Candace Quebe You can pour metal directly into the flask, but the problem is trapped air and gas that can cause the casting to be incomplete.
One way around that is to add gates to the wax models when they're sprued, before the investment is poured. Gates are vents that lead away from the model towards the opposite end away from the pour, but not necessarily completely out of the plaster mold. They give the gas and air places to get trapped away from the model you made.
The jewelry industry uses vacuum assisted pour casting to increase the rate of success. The flask is prepared with a special webbing that burns out along with the wax models and/or flasks that are made for vacuum casting. When it's time to pour, the flask is placed on a silicon pad with an opening connected to a vacuum pump. The vacuum pulls air and gas from the mold as the molten metal fills it.
When you compare the delivery of metal from the crucible between centrifugal casting and vacuum casting, one thing to consider is how effective is the delivery of molten metal into the flask. When you pour metal into the flask, it's slow and if the pour is stuttered or falters, can create cracks or faults in the casting. A centrifuge snaps the metal into the mold quickly and holds it with the force of the centrifuge as it cools.
Can you be successful with vacuum assisted casting? Absolutely. Is it better than the centrifuge? For some things, like big flasks with thick castings. The centrifuge is excellent for detailed castings. Whichever method you choose, with practice it can handle most of your casting needs. Thanks for the question. Joe
Good Demo, Thanks for sharing.....~~
+sam ng Thank you! :^)
Quick question. I’m a pretty good mold maker but just starting my research into metal casting. Do I need to use wax to create the investment mold? I feel I can create the investment mold by creating A silicone positive of my object that the investment can be poured around, than removes pretty easily. If the wax step could be skipped it would save so much time and effort. But I’m sure I’m missing something because I can’t find the answer to the question anywhere. My object “a slightly tweaked rubber duck” is just complicated enough to rule out other casting methods. Thanks in advance for you time, your videos helped me a lot.
Hi Jamie - You can make an RTV mold of a wax model or other objects that you can inject with wax, and then invest it and cast it, but you can't cast non-ferrous metals like silver and gold into a rubber or silicone mold. The metal is too hot and will burn the mold. You can cast using a moldable object using a sand casting method, which doesn't use investment. Low temp metals, like pewter, can be cast in vulcanized rubber molds. Hope this helps. Thanks for watching! Joe
Can you recycle the plaster from the water bucket by drying & crushing it back to a powder?
Not that I know of.
No idea if anyone will see this now but worth a shot! Just wondering at what stage you make the rubber moulds for re-use? And if theres any good videos you reccomend to do this? Also any suggestions on where to source metals for casting e.g. gold. Thanks!!
Hi Caitlin - The first investment mold, which is shown in this video, is destroyed at the end of the process. After the cast pieces are polished, they're molded in natrual rubber or RTV silicone. These are injected with wax to create exact copies of the original and the process starts again. Wax models go into the flasks, etc. As far as videos... I recommend our online classes! If this is something you'd like to learn, check out our online classes at www.silverajewelry.com/classes/default.asp?typeFilter=online. We have a whole series of classes on lost wax casting and wax carving, teaching you all you need to know from a-z, including Lost Wax 2, which covers making molds and casting found objects. They're live on zoom and recordings of our class together are available to watch again afterwards. Thanks for watching!
@@joesilvera8853 Thank you so much for your detailed reply! I'm definitely going to look into those classes- hopefully starting an exciting new journey!
Why spray spray and what kind?
Hi - Thanks for your question. I'm guessing you mean the Vac-u-coat spray that I used before investing? This is a standard step to help prevent air bubbles from sticking to your models. It is sold under different names, like Vac-U=Coat from ProCraft and Vacufilm from Rio Grande. You can find it here: www.riogrande.com/product/rio-vacu-film-concentrates/7021521gp Best and thanks for watching, Joe Silvera
Hi I’ve seen a ton of the bases you attached your sprue tree to have a hole in the area you attach the sprue to. Yours doesn’t have that. I’m worried the metal will go straight out that hole in my investment if that makes sense. Have you seen the bases I’m mentioning?
Hi Matt - There are two reasons a rubber button former base will have a hole, in my experience. 1) it's a hole to fit a large main sprue wax rod (this is a partial hole at the top of the button former), 2) a hole in the base and no rubber button former (this is to screw in a NeuTec style main sprue that includes the button shape. www.riogrande.com/knowledge-hub/articles/why-use-the-neusprue-sprue-and-base-system/
Thanks for watching!
Nice
Very good videos. Very informative. Do you take jobs in for pay. I just am asking because I would like to make a drive sprocket in metal the size of a quarter but I am not that good in making molds.
Hi - Thanks for watching and for your question. I'm teaching jewelry a 110% of my time, so no jobs at this time. However, you can find a list of casters on our site: www.silverajewelry.com/links.asp?cat=13
@@SilveraJewelrySchool I will check it out. Thank you.
Another question.What kind of investment heat plaster are you using for your flasks? Thank you.
Hi - I use either Ransom and Randolf's Ultravest or Allied Minerals SC20. www.ottofrei.com/Allied-Mineral-SC20-Investments?quantity=1&keywords=sc20
Wow, this is actually a really nice video about lost wax casting! I have one question though: you've used a centrifuge for casting. Why is that? Couldn't just pouring the metal (silver?) into the plaster mold produce the same result?
Hi and thanks for your question. In order to fill the mold completely the molten metal requires the help of force to overcome the resistance of gas and air pockets in the mold. A centrifuge applies force that easily overcomes that resistance. Just pouring the metal usually results in incomplete castings. Another common method is a vacuum assisted pour. The steel flask is placed on a vacuum table, and when sealed the vacuum draws air out of the mold, lowering the atmospheric pressure inside the flask. This lower pressure provides the force to help the molten metal fill the mold completely. Thanks again! Joe
I see. Thanks! So does this happen because of the small size of the castings and the molten metals' surface tension? Also, what's the size above which this stops being a problem?
Well, I know from when I did foundry (sculpture size) castings in college that we did not assist the casting with a vacuum, etc. We just poured. The mass of the metal and the construction of the sprues and models was enough to get a successful casting. Jewelry flasks are usually smaller than 4x8 inches and at that size, some sort of additional force is used. I don't know specifically where between jewelry and sculpture additional force is no longer needed. It's a good question! But since I only do jewelry casting, it's outside my expertise. Let me know if you find out.
Actually now that you've mentioned I've realized that you haven't used any sprues for the casting, which probably also makes a big difference. But yeah, it pretty much looks like I'll have to learn about the limits the hard way. Thanks anyway!
Even at this small scale, we use sprues and gates. The terminology can be swapped, but in the video you'll see sprues connecting the models to the button or fill cup. And they're there in the metal casting at the end. What you often don't see in centrifugal casting of jewelry are vents, or small sprues running away from the top of the models to release trapped gasses away from your work. With a good set up and proper casting, they're generally unnecessary.
What are the dimensions of your centrifugal wooden encasement?
I don't have it anymore, but it was basically a few inches larger on each side of the centrifuge arms when fully extended. You can also find pre-made metal casting wells for centrifugal casting machines. Make sure the height and width are larger than your machine.
Thanks for the informative video. Have you ever had any accidents with the centrifuge eg hot molten metal spewing everywhere?
Hi Betty - Thanks for your comment and for watching! :^)
Sometimes a little metal gets past the crucible, but the spinning sends it downwards to the bottom of the box where it sizzles and puts itself out quickly. I've heard of rare failures where the crucible comes loose, but this is usually because of a failure to make sure that either the crucible is correctly put into the cradle or using a wrong size crucible that isn't compatible with your machine. The walls of the box help to keep any spray contained, and you can use safety gear, like a face shield.
It's a good question, but in 25 plus years of casting I've never had more than a few drops of metal spray into the box during any casting.
The key is to balance the machine before each casting, balancing the weight of the crucible, metal and flask against the adjustable weights on the other end of the machine. Thanks again, Joe
It happens to any caster occasionally.
i like that centrifuge is that something you built your self if so can you do a video on how to make one
Hi Michael - Thanks for your comment. I didn't build the centrifuge, just to be clear. That is a machine I purchased almost 20 years ago - wow! Time flies. I built the box to hold it, and put it on casters so I could move it around. Thanks again, Joe
I guess someday 3D printing will really speed this process up. Maybe even silver printing the product in one step
The kind of 3D printing that would make silver printing viable (FDM) will never produce a finish as smooth and flawless as this process. You'll always see the "artifacts" in the printed object, no matter how small they are.
I agree... for now. But as the technology improves, those flaws may be harder to detect or simply just solved in the finishing process. I used to be able to tell 3D printed or CAD work from hand carved, but the programs for creation and the users have become so sophisticated that you can actually replicate some of the wabi-sabi "flaws" of the human hand now. In other words, give it more soul. I've seen computer printed models that were hard to tell that they were made by a machine. The future is coming, and it's looking more like the world of Start Trek every day. :^)
I'm actually doing casting right now with aluminum and silicone. If you use something like ABS you can do a smoothing process with acetone vapors. When the print resolution is high enough, combined with casting, you really can't tell. It at least allows you to more fine tune the model virtually before casting.
No.! 3 D printing will turn this Art into a process !
Doesn't mixing with an electric mixer introduce air into the mixture?
Hi - Good question. Yes. Any mixing will add air to the mix, even by hand. That's why we use the vacuum investment table to pull air bubbles out of the investment. Thanks
What is the brand name of the soldering iron that yo are using?
Hi - It's a Kerr Ultra Waxer 2. Not a soldering iron, though. It's a wax pen .
Do you give online classes? Thank you in advance for your time.
Not at this time, Jean, but when I do I'll announce it on my RUclips channel so please subscribe. Or you can sign up for our email list at SilveraJewelrySchool.com/lists. We do offer workshops at our school in Berkeley, Ca. Thanks! Joe
Interesting how experience saves you so much time and effort. I mix my investment in a plastic bowl with a wooden spoon. I know how thick it has to be and roughly how much I need, so I do it by eye. I then tap out the bubbles using a piece of wood, saving me the expense of a vibration or vaccuum machine. I also paint my waxes with investment before this process so bubbles won't stick to it..
When it comes to the burn out cycle, again, all this waiting for hours is unnessessary. Once my investment has hardened in the flask, I leave it about 15 minutes and put it in a cold kiln set to 149c degrees for dewaxing. I put a tray undernieth to catch the wax so it doesn't screw up the kiln. After about half an hour at that temp I remove the tray with the melted wax and ramp it up to 371c degrees. You hear all sorts of bubbling sounds initially but it soon calms down and you get steam coming out of your inspection hole in the door of the kiln. You wait about half an hour until most of the moisture has evaporated and the jet of steam subsides, I then ramp it up to 732c degrees, leave it for 1.30 hours and its ready to cast. I've got this 8 hour burn out cycle down to 2 1/2 hours and you don't have to leave you're flask overnight to dry..
I preheat my bronze and take the still red hot flask out of the kiln at about 600 degrees. I believe it loses about 100 degrees a minute so you have to get it in the cradle and melt your bronze as quick as you can. I use borax to help the bronze flow and know through experience when its liquid before I let it spin. Overheating it causes the metal to separate so you have to get it just right.
I enjoy 100% success as long as my sprues are well placed.. Whatever methods you use to save time, safety has to be at the forefront of your mind. You can do hundreds of castings but it only takes one mechanical breakdown to send molten bronze at 1100F flying around the room. You always have to be safely behind a screen just in case and never let animals or anything else distract you.
Thanks for sharing your process! Very interesting. There's always a different way to cast, and I can see from your description that you've carefully experimented with your set up to produce reliable results. I just want to note that the processes shown in my video are in line with manufacturers's guidelines for investment and burnout, and are based on their research for best results . Happy casting!
Great video, but I have one question when you put the flask in the crucible is it warm,cold or how should it be? because I trie to make my first casting with a centrifuge and what happened was the metal pierced the plaster leaving the mold empty, so also what would you recommend me to de next time? Thank you
Hi - The flask should be warm, a few hundred degrees below casting temperature or around 950-1000 for fine castings, 900 degrees for thick castings. Make sure when you invest your models that they are not within 1/4" of the sides of the flask and that they're 1/2" below the top of the flask. Too close to the sides and top and the metal can break through. Happy casting!
Joe, can you retrofit or purchase larger flasks if you were wanting to make something like a medallion that was slightly over 4"?
Hi - The system you use will determine how big your flask can be. Centrifuges and vacuum casting machines have maximum flask sizes. If you want to cast something larger, you'll need to source a way of helping the casting with enough force to fill it without getting incomplete castings due to air or gas pockets.
@@SilveraJewelrySchool Thanks. Are you alluding to a custom centrifuge design or are you talking about an industrial level machine at a casting house?
Craig Murray There are casting systems like Neutec from Rio Grande that can handle flasks up to 6x10 inches. Here’s a list of casters on our site: www.silverajewelry.com/links.asp
Thank you
Thank you for watching! Do you work in wax or cast jewelry?
A wooden splash guard around the centrifuge?
Very cool video. This is the first time I've seen a centrifugal casting device. When the wax gets melted out, do you collect it for reuse? It would seem rather wasteful to just burn it all. Is the investment a dangerous material? I'm guessing it's not plaster of Paris and may contain silica? I would love to have a go at this myself.
Hi - Thanks for watching. You have the option to steam out wax before burnout if you're using lower temperature injection waxes. Carving waxes are harder to steam out. But it's usually mixed with the sprue wax and water and not usable, But steaming it out makes the burnout cleaner with less odor and fumes. We use a specialty investment for casting that is similar to plaster but has ingredients to make it better for high temp burnout. You do have to be careful whenever using investment. I wear a respirator. Thanks again, Joe
What is that tool your using to put the wax on, the one your dipping into the hard wax....I've been teaching myself how to do this stuff but one if the hardest things to learn about are all the tools, no internet searches I've used are any good. I've seen something that looks like it even lays wax ( not a batik pen) but cant find it anywhere. I have a lot of questions, but never receive answers.
Hi Hex! It's a wax pen. That model is a Kerr wax worker, but you can find inexpensive wax pens from battery powered SuperMax pens, and electric Foredom Wax Carvers or the Arbe Wax pen. They're great for welding cracks, build up and lots more! We cover wax pens and lots more in our Lost Wax 1 - Basics workshop, which is also available live online. SilveraJewelry.com/classes
@@SilveraJewelrySchool every time I entered searches for wax pens I got wax carvers only, I've got one of those 2 arm dental heat deals ..but an Arbe wax pen? I'll look it up, something that I've seen but haven't been able to replicate was the laying down of hot wax onto a mold, making patterns or frames that then come right off. Even with mold release hot wax sticks, and its too liquidy, but the wax pen I saw was laying a thick line, like you'd expect from Elmer's glue. I'll check out that episode that covers them as well thanks!
Amazing. Is just candle wax or something more special?
You could make a model out of anything that burns out cleanly, even candle wax. But we use waxes developed for jewelry that are better to work with and can even be sawn, filed and sanded. Check out the waxes at www.silverajewelry.com/store/w/c/355/t/Waxes/browse.asp Thanks for watching!
@@SilveraJewelrySchool amazing. Thanks.
@@SilveraJewelrySchool thanks.
what is the solution you put into the rock tumbler barrel with the shot and jewellery?
Hi Baz - I'm using a rotary rock tumbler. It's loaded with 2 pounds of mixed shapes of stainless steel shot. To lubricate the tumbling, I use enough water to just cover the surface of the shot, and a drop of tumbling compound, like ShineBrite, or a drop of Dawn blue degreasing liquid dish soap. This kind of soap is the cleanest with the least additives for tumbling, or for cleaning your metal. So something similar to that would work fine. Just a drop! Too much and the suds are insane. Happy tumbling and thanks for watching! - Joe Silvera
Thank you for the informative reply :) May I also ask if using a tumbler would work to burnish aluminium parts? I'm currently sanding craft items and then polishing them, this would be a welcome alternative.
What kind of plaster is that? If you just poured it instead of doing the centrifugal system would u get too many voids?
Hi - I use Kerr Satin 20 investment, which is different from regular plaster. It's formulated for the intense heat and duration of a casting burnouts. Good question about pouring. If you pour metal into the investment mold you are likely to get voids in the casting from trapped air or gas. But if you either use a centrifuge or do a vacuum assisted pour, you can get great results. Thanks for watching!
Please reply with a parts list and links where I can purchase. (Centrifuge, vacuum chamber, etc.)
OttoFrei.com sells a good casting kit including a kiln and centrifugal casting machine: www.ottofrei.com/Otto-Frei-Jewelry-Casting-Kit-2-Pro-110V. That will give you a basic list of parts for casting. You will need a casting torch (oxygen/propane is best) or an electro melt furnace to melt the metal. The torch works best for both vacuum casting and the centrifuge. Thanks for watching!
Silvera Jewelry School
Thank you for this educational video. I did have a question I was hoping you could answer for me.
The plaster you use. Is it a special blend mix or it plaster of Paris? Just curious because I have seen other videos
where the mold has to be broken open versus disintegrating in water. Thank you :D
Hi - Thanks for watching. Special investment is recommended for jewelry casting, not plaster that you would use for sculpture, etc. Casting investment is mixed with materials that allow it to be fired at temps upwards of 1300°, to receive molten metal that is hotter than that, and to have very fine detail for the best casting. Some investments are formulated for purging in water, or to be more receptive to being removed by breaking the investment. For example, investment formulated for casting stones in place needs to be removed when the mold is cold, so it's made to break up easily. Most investments will remove fairly easily by breaking the investment mold after casting, even just by rapping the steel flask with a mallet, especially if the flasks are small. Best, Joe
I'm a little late to this video, but it's a great demo!
Can I ask - I have the same kiln (just got it). What is your burnout temp schedule for it? I've yet to use it, and haven't figured out how best to use it compared to my homemade one I used to use (talk about a guessing game!). Any suggestions? Do you ever steam the wax out first? That's what I used to have to do with my homemade kiln, but my understanding was that with this kiln I don't have to.
Thanks! Great video!
+kathleen connor Hi Kathleen - I use Kerr Satin Cast 20 and they have a great PDF at The art and science of lost wax casting. - Kerr Casting that includes mixing instructions and sample burnout schedules. You can use the sample schedules to program your kiln.
A steam de-waxer is on my wish list, but I don't have one yet. Steam de waxing is usually optional. It's a way to decrease smoke and odor during burnout. A burnout kiln should have a hole in the top to release the smoke.
The burnout temp. on the majority of items is 850cent.
I want to make make a silver belt buckle. I got kiln to do the lost wax brun out. I got a oxygen/kerosene tourch, and made me top vaccum. Here is my question.:
Hiw do I know that the solver is hot enough to Puerto it into the mold?
Hi - The silver will melt into a smooth rounded puddle. The surface will look like a mirror and can also appear to move and roll. If you're melting in a crucible with a handle you can gently swirl the liquid metal in the crucible to be sure that there are no solids left. Don't let the metal boil - it will look like the surface is quivering and jumping. Good luck and be safe. Be sure to wear tinted glasses to avoid getting cataracts from repeated exposure to infrared light from the hot metal and UV rays from the torch.
You humble me with your answer. My most deepest gratitude.
I have seen some videos that teaches to set various temperatures program on the kiln. Do I have to do that way or can I go up to the 1350f and then down to 1000f?
Isa Abd Rahman Sosa-Dominguez Hi -it’s best to run your kiln through a number of stages, slowly ramping your temperature up to the maximum, and then slowly dropping it down to casting temperature. Sample burn out kiln programs are offered by the manufacturers of the casting investment on their websites. Best, Joe
Just wondering what made you tumble the cast pieces before doing the end finishing instead of tumbling at the end? Also I was just wondering how long you usually tumble your pieces for?
+Adam Lagace Hi. Thanks for watching my video. - Tumbling is an option for a final finish. First I cut off the sprues, grind and clean the nubs left by the sprues and blend those areas back into the rest of the finish. Then I touch up any flaws up to about 400-600 grit finish. Finally, I tumble in stainless steel shot or with fine steel pins for up to 2 hours to burnish the metal to a high luster. Burnishing has the advantage of not removing any additional metal and also closing any fine pits or porosity. Hand finishing and polishing with abrasives can reveal any fire stain from casting, and may require removing more of your carved details. Burnishing can polish the fine silver loam from pickling after casting and preserve your carving. Best, Joe
very...very nice....congratulations...... São Paulo - Capital - Brasil
+oodimvale Thank you!
Silvera Jewelry School lol
Great video, thanks for posting! I'm looking to cast a 2" puck of gold, and we're looking to use a lost wax method. The final part will be ~1mm thick by 2". Do you have any suggestions on casting something like this without a centrifuge? We have a vacuum oven (which was how I was planning on baking out the wax) and I was thinking that we might get away with some small vents at the edge of the puck if we set the investment into the vacuum oven when we pour it. If you see anything egregious about that method, please stop me before I waste a lot of time :)
HI - Thanks for watching and your question. If you have trouble filling the entire 2" diameter 1mm sheet, the model may be too thin. You may need to up it to 1.3mm (16 gauge). Good luck with your casting. Joe
Super
what is the process to balance the arm?
Hi! The exact method to loosen the arm for balancing may vary. Read any instructions that came with your centrifuge. But basically you release the arm so that it can move like a balance. Load the flask in the cradle, the crucible and the metal weighed for casting. Move the weights on the other and add or subtract weights until the arm is balanced. Thanks for watching!
@@SilveraJewelrySchool Thank you for the clear explanation! I started silversmithing in 1969 but had to quit about 9 years later because I couldn't have little kids running around the flames, etc. I just started doing custom leather instead. But, I still have my bench, tools and equipment and am setting it all up again..The instructions that came with my centrifugal casting machine are long gone by now so I am thankful you answered my question and reminded me! Your video has such a clear explanation. Thank you so much!
What temperature in the kiln?
At the end of the burnout cycle the kiln holds between 900 - 1050° F for casting.
was there a reason you didnt vacuum cast but instead used the centrifuge?
+pikkilo Getting a good casting is about force: getting more than the force of gravity applied to the molten metal so that it fills the mold. Vacuum assisted casting lowers the atmospheric pressure in the mold and forces the metal into the recesses. New vacuum machines are better than they used to be, but a centrifuge has even more force applied to the metal for more reliable casting. Also, the centrifuge takes care of fast and accurate delivery of the molten metal to the models. Vacuum assisted casts still depend on a person to pour the metal (unless you have a thousands of dollars for an industrial model). If you stutter the pour or mess up, oops, bad casting. I've always preferred a centrifuge over vacuum casting.
How can i set this up? links please!
I'd suggest taking a class to learn how to use the equipment. We offer online casting classes with instruction on how to make wax models and how to cast. SilveraJewelrySchool.com/classes. Casting kits are for sale at RioGrande.com and OttoFrei.com
do not forget to cover the inner surface of the cylinder with asbestos tape to facilitate the expansion of the jar ....
No asbestos in our studio/classroom. Not worth the health risk.
Good morning, Joe.
Is the plaster you use is refractory or common plaster?
alcides silva we use casting investment for jewelry. Don't use regular plaster it can't take the burnout and isn't as good
Awesome
Nice video looking for a one where you teach how to make wax reproductions
I did not see the main part...How do you do the wax models?
Hi Jorge - Thanks for your comment. Yup, this video is on the casting process, so it picks up after the models are complete. Making wax models is a whole process in itself and the focus of our classes here at Silvera Jewelry School. But we use this video as well as live demonstrations to illustrate the lost wax process. Best, Joe
what is that powder?
Hi KC - I'm guessing that you mean the investment that I mixed with water for the mold. It's casting investment. You can buy it from jewelry suppliers. It looks like simple plaster but is not the same, since it has to be fired to high temperature in the kiln. Thanks for watching!
Hi, what is the name of this white powder that is used? Thanks
Hi. It’s called investment. I use Allied Minerals SC20 (formerly known as Kerr Satin Cast SC20. Thanks for watching
Just a quick update that Kerr stopped making SC20, so now it's available as Allied Minerals SC20
could you cast aluminum this way? :)
Did you make the centrifuge?
No. I'm using a Kerr brand broken arm centrifuge. Had it for over 20 years.
Te saludo desde Colombia 🇨🇴✔️ S.A
No mention of Borax.
Why not make rubber molds from wax model.
Making a rubber mold from a wax model is an alternative. Just to be clear, you can't cast precious metals or base metals into a rubber mold. Only low temp metals like pewter, etc. I don't use borax. I use boric acid. It's a higher temp an is commonly used for casting jewelry and ingots. It's a short video, not a tutorial. Can't put everything in there. :^) Thanks for watching!
whats the correct burnout temperature of the wax you use?
Hi - Thanks for your question. Since there's more to it than temperature for the burnout, here's a link to a PDF from Satin Cast 20 investment re: burnout schedules and temperatures. romanoff.com/media/pdf/76-106-NY.pdf
All the best and thanks for watching. Joe
@@SilveraJewelrySchool thank you for the link, and thank you for this great video.
Oops, the link no longer exists.
thanks very good!
what tourch is best for casting?
+Anthony Berry I like oxygen and propane torches. A casting torch model is the best. You can also use acetylene. Thanks! Joe
Well done but I don't use a spin type .
I did this in college. I still don't know why it's called "lost" wax casting. It's removed... but that still makes no sense. In fact, the plaster is "lost" too, so...?
The name is focused on the wax. It's melted out during the burnout and replaced with metal during casting. It may be a carry over from other languages, like "cire perdue" in French. With 7000 years of metalsmithing history, a lot of names are passed down. It wasn't alway investment for the mold. Ceramic (clay molds like in Ashanti casting), sand, etc have been used, too, some of which could be reused a couple of times. Thanks for watching!
cool thanks
Hey are you still active I have a question
Ask away. :^)
I just brought the same neycraft oven what setting do you use for the wax burnout? Does it ramp up and hold its self or do you have to manually adjust it your self?
@@deeaikens9843 Sorry I just saw your reply. You need to set the Neycraft manually. It doesn't have a controller. So keep notes for dial positions. Or you can buy a separate kiln minder that you can program like this one that will hold a lot of programs for burnout, etc. www.riogrande.com/product/kilnminder-oven-controller-k4e/703094
What temp do you use to cure the investment and what temp do you use to burn out the wax? I’m afraid to do these wax models because they took a lot of time to make
@@deeaikens9843 Hi - So you let the investment harden at room temperature for 2 hours after investing. The kiln program for the burnout varies according to the size and number of flasks you're burning out. The investment manufacturers offer free pdfs with instructions on burnout schedules/temps and investing. Like this one: docs.wixstatic.com/ugd/cc5f22_c4ac76d773c94aa5b8ceff61af77b72f.pdf
Best of luck with your project! Joe
Лайк та переглядів, вашому каналу.
Could I melt a candle to use as my wax? Thanks!
ebaymaster You can make a model out of anything that meets the specs to burn out in the kiln cleanly. Jewelry waxes don't leave a lot of soot and mess to deal with, so I would recommend using carving or build up wax from a jewelry supplier. Sculptors (as in foundry casting) use paraffin wax that is more similar to bees wax. That could be used too and you may be able to find it at an art supply.
***** Thank you for your helpful reply!
what kind of plaster do You use?
Hi - I use Kerr Satin 20 investment, which is different from regular plaster. It's formulated for the intense heat and duration of a casting burnouts. Thanks for watching!
Thank You very much. I subscribed to Your channel.
good share for that ,silica sol lost wax casting
a drop of dish soap in the mud prvents air bubbles, jsyk
No it doesn't it makes it worse, just water and mix it slowly so you do not put air in the mixture.
Your work is wonderful and is like our work a lot, I have a question Can I find a job in the field of the Rings industry in America or Europe, and how do 💍💎💍💎💍
Hi Youcef - Thanks! Appreciate it. Getting into the jewelry industry in America and Europe takes time and a good portfolio of jewelry that demonstrates your skills. And patience while you contact jewelers for opportunities to work. If you can get certified by taking the tests at jewelers.org www.jewelers.org/ja/careers-education/certification. Good luck! Joe
Did you buy your centrifuge or make it?
+Candace Quebe It's best to buy it. A centrifuge is built around a powerful spring, which should only be serviced by a professional. In the 20+ years I've had my centrifuge, it's never had to be serviced. You can buy it from a jewelry supplier, like RioGrande.com, or OttoFrei.com. Make sure you get some training on safe use of a centrifuge, just as you would with a vacuum assisted casting machine. We offer casting workshops at Silvera Jewelry School, our school in Berkeley, CA. But there are lots of good jewelry schools all over the US now. Best! Joe
+Silvera Jewelry School Thank you very much for your help, I have one more question is there anything cheaper than investment plaster something that I can get by with? I would like to test out casting before I get this expensive plaster.
+Candace Quebe Is your torch fueled by propane?
+Candace Quebe Hi again! I would recommend just buying a small amount of the correct investment plaster. Using the wrong kind can skew your results and be disappointing.
+Candace Quebe I use two kinds: an acetylene torch (it draws it's own oxygen, so single acetylene tank). or a oxygen and propane casting torch. If you're casting a small amount, like less than 2 ounces, and especially if you can preheat your crucible in the kiln at the end of the burnout, you may be able to get away with a plumbers torch from the hardware store: propane or mapp gas, until you're ready to invest in a better torch.
Holy shit is that scary, so many other safer methods . Please put a disclaimer on this content. That spinner should have a lid.
I appreciate your comment. It’s true that these machines are set into casting wells with lids, which I also recommend to students setting up a new system. I can also let you know that I have used centrifuges for casting for thirty years and have never been injured, even without a lid. What’s important to understand is the physics of a centrifuge causes any spills to move in the same plane as the machine. So metal will hit the walls inside the well, and it will not fly up and out of the box. As a casting teacher I’m way more concerned about student injuries when they’re working with open crucibles of molten metals for pouring into flasks. The rules for safely using a centrifuge are simple and these machines offer s lot of reliability and accuracy. Thanks again.