Grinding the cat-litter in a ordinary kitchen- blender/mixer makes it fine as powder in a matter of seconds. This way I made about 40Kg greensand a couple of months ago. Despite what some experts are saying, it really does the job good. Though it required a lot of mulling before i found the strength of the sand satisfying. Mulling in this case was done by hand.. and took me about 6 hrs of manual hard labor. Next project will be to make a muller ;) Good Luck! and thanks for sharing =)
its been a while since you did this video. I'm interested in what you've learned since then. Particularly, on making optimal greensand. I want to thank you for taking the time and effort to post this. It's folks like you that fuel others in a creative path.
Not a problem. If you want a relatively smooth finish for castings, then I would suggest using a thin layer of Talc on the form used to make the mold. This also helps with the removal of the form from the mold.
Hi, thanks for your comment. I am a home hobbiest and never claimed to be an expert. I searched for vids on how to make greensand and only found incomplete information. I like to document my progress and hopefully help others at the same time. You say I am doing it very wrong, yet my greensand works fantastic. There are many ways to accomplish most tasks, yes, some better than others. Rather than just criticizing maybe you can offer advice to help me and other viewers improve our skills? Thanks.
Very cool! I'm gonna have to try this. My first mold material was just dirt, I went outside and cut my shape into the dirt. It worked decently well, but the dirt was too wet. I didn't have a steam explosion, luckily, but the water content of in the dirt boiled immediately on contact with the molten aluminum, which resulted in a lot of little air bubbles in the surface of the cast. Overall though, for my first time it ended up pretty good. I'll have to look into making some of this stuff though.
Screening together your dry powders will mix them thoroughly and adding small amounts of water and screening occassionally will disperse the water more evenly while continuing to mix.
Is crushed limestone a suitable casting sand? It is very fine, clumps together easily when compacted, and would produce a terrific, smooth finish on the aluminum casting.
+GTgyro Crushed limestone is a bad idea. The water soaks into the limestone and then often the individual grains pop when poured. You get a casting that has a lot of internal gas bubbles.
Nice video! All I might mention is that when we used bentonite powder in the paper mill I worked at it come in bags labelling it as a carcinogen. Some sort of dust mask might be a good idea. Any fine powder is bad to breathe regardless. Nice work though.
Thanks for your video,it helped set me on the path to casting aluminium bow risers.I'm building knock down re curves with hard maple and carbon fiber limbs.I'm using AFS 100 sand, bentonite and oil.I'm getting great detail with little finish work.
+Joe Longstaff Sand with oil and bentonite is called petrobond sand. The disadvantage is that it is considered a hazardous waste when you are done with it. When you pour it, it produces a lot of smoke that technically requires a scrubber to clean the air and if you use too much oil, the molding sand catches fire if you shake the molds out hot. Petrobond does not self mix like water with clay, so typically, when we used petrobond, it had to be run through a muller about every third or fourth time it was used, as you added new oil to replace that which burned off. The big advantage of petrobond is that you can make a mold and leave it overnight without worrying about it drying out. If you break off a section, it is easier to repair than water based molding sand.
A friend of mine has used sand for lead casting with some success however you can cast lead in a mold made of wood too... of course the wood mold could likely only be used once but it might be a simpler option. Thanks for watching.
I had considered the catlitter thing before doing this and decided against it. The reason is that while yes, clumping litter does contain bentonite -- it is chunky. The bentonite I purchased was ultra fine, like flour, which allows it to "coat" the grains of sand. I'm not sure that you could grind cat litter that well. If you try it please let us know the results! Thank you very much for watching and commenting.
Nice video. Would this mix work for casting lead? I'm trying to make some simple round wheel weights for a tractor out of car wheel balancing weights. Thanks.
Many years ago we made 12 to 16 ounce "bell shaped" surf fishing weights from Padre Island. beach sand molds. That sand is a little too spherical to cast much detail. We were using old recycled fishing weights and it is nearly pure lead. One or two of per cent tin added can get you better mold fill-out. Consult the Lyman Cast Bullet Handbook available at a library. Will you use steel clips?
I found a source of Bentonite. A well drilling company just a few miles away sells 50 pound bags of it for $17.50! I don't need 50 pounds, but if I haveto buy more to save some money, I will. Now I'm having trouble tracking down silica sand. The nearest Carquest to me is about 10 miles away, but I don't drive, so that's out of the question. Home Depot doesn't have the right stuff, too course. I'm looking at pool stores, filter sand might work.
Check the bag of your kitty litter. Most cheap ones are pure bentonite clay. Smaller applications you can grind it up pretty much which ever way. For larger batches, as the one here i'd say stick it in a cement mixer with a bunch of large steel bearing balls, and stick a lid over the top. It's going to be noisy as hell. Tilt the mixer to dump the lot through a screen to remove the balls, and start putting sand + bentonite back in to the mixer. Add water to consistency, and your done. Beats tarp.
Can you reuse this sand after molding ? I have already built my furnace.im lost on the sand. Can you please write a list of materials needed and where to buy from thanks
+Shawn P The advantage of sand bonded with clay and water is that it can be reused many times. The number of times depends a lot on what metal you are pouring. Aluminum is typically poured at 1300 degrees. That temperature will not burn out the clay. We use ours hundreds of times. Iron and brass pour at much hotter temperatures. Typically those production shops replace 10% of their sand each time they use it. The reason is that at the high temperatures that they pour at, Bentonite clay, which is an expanding clay, turns to Illite clay, which is not expanding. Non-expanding clays don't hold the sand together. Only the portion right next to the casting has the clay converted to illite, so you don't completely lose the strength after one pour. In a home foundry, you can keep adding a little clay as the sand gets weaker till you start to have permeability problems that manifest themselves a blows. Those are gas defects in the form of large holes in the casting or bubbles on the surface. Those can also come from just using sand that is too wet. I buy my clay from Carpenter Brothers in Muskegon, but other companies sell it as well. The sand should be one that is low in limestone or other particles. You want a clean silica sand if you are buying inexpensive sand. Often you can find it as play sand at building supply houses. It is typically well sorted and has very little clay in it. You can also use 2NS sand from a gravel pit. Fine sand produces a really nice finish on the casting but is not very forgiving if the sand is too wet. You end up with gas defects. Coarse sand is much more forgiving because the open permeability allows gas to escape through the pores of the sand at a higher rate than does fine sand. The disadvantage is that the casting is rougher. In the industry, aluminum shops typically use fine sand. Brass and iron shops use coarse sand.
I saw a video of a guy doing 10% cat litter and 90% finely grained sand to make good consistency... would that be cheaper than your material? It still does the job for "metal casting" if that is the intention lol
good job, but why not consider a ½" drill and a mixing paddle ... put all in a container from 5 to 25 gallons and whip it out in a matter of a minute or two? Good mix and complete water penetration is key, but the plastic process, although very clever, is also very time consuming ... keep it up, I learned a couple things and appreciate it@
Don't know if they have a location in your vicinity but they sell bentonite at "ditch witch" retailers. I think it's fifty pound bags. We use it for priming concrete pump lines. Probably cheaper than getting it by mail.
The sand you are using is awfully coarse for typical molding sand. You might want to get some 2NS sand from a concrete supply or gravel pit. The problem with gravel pit sand is that depending upon the state you are in, it might contain a lot of limestone, which will hurt the finish. If there is a foundry supply in the area, buy sand with an AFS grain fineness of 70 or finer. The higher the number, the finer the sand. I run a production and prototype foundry and we use an AFS 100 grain fineness sand. We have used AFS 400 sand in the past. When I was young, we would mix sand with an eastern coal shovel on a concrete floor.. Just place the sand and bentonite together and turn it over several times till it is well mixed. We always used a garden hose with a spray nozzle to wet the sand. Typically, you want to let the sand sit for an hour or so after you have cut / mixed it to allow the moisture to become more uniform throughout the sand. Mix the sand and water with a shovel. Store it in a plastic bucket with a lit to keep it from drying out. You can cleanup the sand with a broom when you are done. You didn't say if you bought southern or western bentonite. Typically, if you use rounded silica sand, you will want a mixture of 50/50 western and southern bentonite for aluminum. Western bentonite is stronger than southern bentonite. Too much western and the sand wants to stick together in hard lumps after you have poured your molds. We typically run our mixture at 7.5%, not 12% clay. That is a little high. More clay reduces the permeability of the sand, making it more likely that if the sand is a little too wet, you will get steam bubbles that will push through the metal as opposed to going out through the sand. These are called blows. If the sand is wet enough, it will rocket out of the sprue (the sprue is the hole that you pour the metal into the mold), something fairly dangerous. The sand should stick together like snow does, when you squeeze it. You should be able to take the squeezed sand with two fingers, and shake it lightly without if coming apart. If it crumbles, it is too dry. It should not stick to your hand. If it sticks to your hand, it is too wet. You will find that the green sand would have worked much better if you had put the clay in a bucket with water and boiled it. This activates the clay. Otherwise, it will only slowly become active as you pour metal into the molds and the clay gets steamed. Over time the sand will nearly double in strength. With this level of clay and the strength it will achieve, it will be difficult to get a smooth casting without the sue of a fine screen (called a riddle) to break up the lumps as you put sand in your mold. You should use a riddle with 1/8" x 1/8" holes. You can order these from companies such as Freeman Supply and are known as a #8 riddle. The number is the number of wires per inch, or you can make your own with hardware wire screen. I would be careful if you decide to use plaster. Plaster must be very dry before you pour it. Typically, you want to bake a plaster mold in an oven for at lease 8 hours at 600 degrees before pouring it, to get the moisture out. Failing to do this often results in aluminum foam as opposed to solid aluminum parts.
+Julio says To activate bentonite, put it in boiling water for 5 minutes before using. The boiling water will hydrate the silicate layers. Once activated, you do not need to repeat this process, even if your sand drys out completely. The interstitial water will remain there. This activation makes the sand properly sticky. If you use bentonite sand that has not been activated, the sand will be weak until it has been used several times with metal having been poured into it. The steam activates the sand. In a production foundry, you typically add a little new sand on a regular basis. Since it is not a huge part of the whole, it doesn't significantly weaken the sand initially and it picks up strength as it gets used, from the steam generated in the pour. There are two types of bentonite. Southern and Western bentonite. I recommend western for anyone using natural sand and anyone not using a muller to process the sand. Western is much stronger than southern but if you pour aluminum in an automated system, the sand will stick together so well that it will be hard to push through a riddle and will load up on aerator fingers. By hand mixing, that is typically not a problem and as long as not mulled, it is easier to work with. We typically use 7 % by weight, bentonite to sand for hand molding. I typically use around 3% water in the mix. You can tell if the moisture is correct by grabbing a handful of sand and squeezing it. It should only barely stick to your hand and it you should be able to see the lines of your hand in the sand. When you take the piece that you just squeezed, you should be able to pick it up with two fingers and have it hold together. After you shakeout your molding sand, it is best to add the new water right away and then store it in a sealed plastic bucket. This will allow the water to spread evenly throughout the sand so that it works evenly when you use it again.
Hi cfjulian1225 I was afk for weekend, many thanks for the reply, I've yet to hear anyone speak of activation so I'm taking notes of all you advise... right now I've a tester pack ready, 1kg (1000gm) of Silica sand, 125gm of bentonite fresh from the blender.. also a mister of water.. oh and a kettle :D Im ready to follow your steps with a sample batch, the ''boil before use'' still raises question, if I boil the clay, or add boiling water.. do I let it dry, then mix with sand etc? Im thinking the wet clay wont mix, just want to do it correct, so if you could give me a step by step with the measurements im looking at, ill do it today, and get back to you :).. i really appreciate your tips and advice, thanks so much for sharing your experience in this science.. :)
+Julio says It would be best to let the clay dry out again before mixing it with the sand if you are using a mechanical mixer. If you are mixing by hand, depending upon the size of batch you make, you could activate the clay after mixing it with sand and adding water. The issue is that the clay needs to be steamed. If you have a metal garbage can, or and old drum, mix up the sand and clay with a little extra water then heat sand, clay and water in the drum over a fire till you see a good amount of steam coming out the top. Once you have steam going all the way through the sand and clay, the clay will activate itself. Let it all cool back down before you try to use it. If you are only mixing 1Kg, you could probably do it in a pan on a stove top. Be careful not to melt the pan. You can stir it to help distribute the heat.
To get really good results with mixing, put the prepared green sand into a 5 gallon bucket with a tight fitting lid. Put the bucket in your clothes dryer with the heat on the lowest setting possible. put in some blankets, pillows, or cardboard boxes to sort of keep it from damaging the bucket or dryer. OR - if you gonna be doing a lot of this stuff, get an old dryer and disconnect the heater..... WaLa !!! a mulling machine
IF cat litter is pure bentonite, then it is easy access anywhere (even in Australia!) A good ball mill will do thejob of educing it into talc like powder
RE: Petrobond replacement, use the same mix as in the video, but use a synthetic 2 cycle oil instead of water. The oil I use is AMS Oil 100:1 seams to work very well. I just start adding 2 oz's at a time till I get close then a squirt oil can to finish. I'm building a small Muller to make things easier and faster.
Chris Peterson that would work, if you had one...if you don't, they are a little pricey to buy...you can pick up a tarp at the dollar store for 2 bucks.....or a tray (if you're making a small batch) for $4.00.
10 bucks at a farmer's co-op will get you fifty pounds of super fine bentonite clay. Kitty litter is a pain in the butt to get ground down to a useful consistancy.
Thanks for posting.I am sure that you will find after mulling the mixture will give a lot better results. Good job as far as you have gone but the sand as shown is not there yet.The the devil is in the details and mulling is the thing you might find gives you much better results. The clay need to be pounded into the sand like you wouldn't believe just like Mr B says.
Boris Sabo that would work too but I don't think you can get 50 lbs of sand into a bucket.....plus it is extremely dry so it might be hard to mix....I know I burned out a porter cable drill mixing mastic......(it wasn't a slow speed makita :-( I didn't have one at the time)
Boris Sabo Not sure where you live, but I saw a small cement mixer at home depot...looked like it was about 5 gallons (it was about the size of one of those 5 gallon plastic buckets)....It actually would be the perfect size for these projects as well as home owners who had small jobs and had no need for the tow behind ones....
+Boris Sabo When you mix your sand initially, mix the dry sand with the dry clay. Boil the clay first, then let it dry out before doing this. Mixing in a bucket with a drill will not kill the motor if dry. Once the clay and sand are mixed, you can just spray the sand pile down with a garden hose and turn it over a few times with a shovel, then let it sit overnight. If you are using western bentonite, a light spray of water on top will leave a crust that protects the sand from drying out. Just push aside the dry stuff on top and use the stuff below. I typically just spray the top of the pile lightly before using it.
Nice explanation, however, I just don't get why you cut the bag like that :) in the bottom first and then a hook-cut so it flops open and just spills the internals.
It seems dry to me. Your mold will wash when you pour. I was a molder for years. I am thinking of pouring aluminum in plaster of Paris. Please let me know if you decide to use plaster. I would really like to know I helped.
Tried casting into plaster of paris early in my attempts. Terrible results. LOTS of bubbling...picture molten aluminum volcano lava...dangerous. My hypothesis is that the temp of the aluminum actually drove the water in the plaster crystal out and made mini (and not so mini) steam explosions.
Fred Landavazo IV I am not debating. Just making suggestions. Did you vent the risers? Maybe the plaster was not dry enough. I plan to try this one day and I will beware of your warning. Maybe bake in oven?
gypsum has a LOT of water bound up into it chemically; the heat of the molten metal is enough to break the bonds and drive the water out, even in a plaster casting that's completely "dried"..... a better option would be investment clay.....it's how they do lost wax castings with bronze & brass.(and gold & silver)....however, it's a single use type thing...the heat of the metal breaks down the material at a chemical level, so the mold would not be reusable.... A plaster mold will hold up to a couple of casts with something low temp like lead, but at the temps of aluminum, brass & bronze, molds just do not hold up.... there's a reason the industries use sand casting.... you can get modest results for brass and aluminum using wallboard mud as an investment, (coating a foam form), and then putting it in sand for support, but good quality fine-grained sand is going to be faster and more simply accomplished with fewer steps....
TheElderScrollsKing i believe its because properly mixed and tempered green sand will mold if left allone for a week or more turning green but heck if i know
The sand originally used for casting was naturally occurring. It forms in river beds and is a mixture of sand and natural clay . River bed sand has rounded grains from constant erosion by the moving water. These rounded grains maintain gaps between them even when compressed, allowing the mould to remain porous (as opposed to 'sharp' sands which tend to pack together more tightly) The green colour comes from minerals present in the clay.
Because with the Sand it lets the gasses through and if u used straight clay they gasses would get trapped and make bubbles in your cast. Hope this helps
+basement_sawyer Be careful of which pool filter sand you use. Don't use the stuff called diatomaceous earth. Although it is silica, it is the internal structure of a small critter called a diatom. This stuff collects in deep ocean areas with little other sediment being added. The disadvantage is that the spines easily break off and produce respirable silica. This dust will give you silicosis.
i am going to use recycled cat litter because i am green and AL gore said never wast and be a good little uneducated prius driver with a clean heart :}
Nice vid..Sorry to burst Ur bubble,,The process you use is fine for the 1st 1/2,actually well detailed,But that silica sand is only 00 grade.So it does not matter how fine ur bentonite clay is.The surface finish will only be as fine/detailed as ur 00 silica sand.Bentonite clay is expensive as hell.Why not just use fire clay?It is less than $20 for 10kg ..You will then have change left to buy a sieve/riddle.I hope that white thing was NOT polystyrene,the thing U put the cope/drag UPSIDE down on??
man thats fucking insane. call any local ceramics, pottery place supply place and they will have bentonite clay. usually they will sell it by the pound so you dont need to get a a freaking 50 dollar bag when you need six pounds of it. petrobond for sale website seems to be the ticket. guy is selling pre mulled petro bond for about a buck a pound shipped.
Of all of the videos on YT about home-making Green Sand, this one is the clearest and easiest to follow. Great job!
This video got me to sub!
That's how I started too. Just used dirt and sifted out the rocks. Eventually I added some motor oil as a binding agent. It worked OK. Keep it up!
Grinding the cat-litter in a ordinary kitchen- blender/mixer makes it fine as powder in a matter of seconds. This way I made about 40Kg greensand a couple of months ago. Despite what some experts are saying, it really does the job good. Though it required a lot of mulling before i found the strength of the sand satisfying. Mulling in this case was done by hand.. and took me about 6 hrs of manual hard labor. Next project will be to make a muller ;)
Good Luck! and thanks for sharing =)
its been a while since you did this video. I'm interested in what you've learned since then. Particularly, on making optimal greensand.
I want to thank you for taking the time and effort to post this.
It's folks like you that fuel others in a creative path.
Not a problem. If you want a relatively smooth finish for castings, then I would suggest using a thin layer of Talc on the form used to make the mold. This also helps with the removal of the form from the mold.
Interesting video. I have question where did you get the those sand and clay.i wanna know can I use sand from beach and earth clay? Please
Hi, thanks for your comment. I am a home hobbiest and never claimed to be an expert. I searched for vids on how to make greensand and only found incomplete information. I like to document my progress and hopefully help others at the same time. You say I am doing it very wrong, yet my greensand works fantastic. There are many ways to accomplish most tasks, yes, some better than others. Rather than just criticizing maybe you can offer advice to help me and other viewers improve our skills? Thanks.
Simple and straightforward, right up my alley. Thanks!
Very cool! I'm gonna have to try this. My first mold material was just dirt, I went outside and cut my shape into the dirt. It worked decently well, but the dirt was too wet. I didn't have a steam explosion, luckily, but the water content of in the dirt boiled immediately on contact with the molten aluminum, which resulted in a lot of little air bubbles in the surface of the cast. Overall though, for my first time it ended up pretty good. I'll have to look into making some of this stuff though.
Screening together your dry powders will mix them thoroughly and adding small amounts of water and screening occassionally will disperse the water more evenly while continuing to mix.
Bentonite Clay has a lot of versatility. Thank you for the tip.
Is crushed limestone a suitable casting sand? It is very fine, clumps together easily when compacted, and would produce a terrific, smooth finish on the aluminum casting.
+GTgyro Crushed limestone is a bad idea. The water soaks into the limestone and then often the individual grains pop when poured. You get a casting that has a lot of internal gas bubbles.
Nice video! All I might mention is that when we used bentonite powder in the paper mill I worked at it come in bags labelling it as a carcinogen. Some sort of dust mask might be a good idea. Any fine powder is bad to breathe regardless. Nice work though.
Thanks for your video,it helped set me on the path to casting aluminium bow risers.I'm building knock down re curves with hard maple and carbon fiber limbs.I'm using AFS 100 sand, bentonite and oil.I'm getting great detail with little finish work.
+Joe Longstaff Sand with oil and bentonite is called petrobond sand. The disadvantage is that it is considered a hazardous waste when you are done with it. When you pour it, it produces a lot of smoke that technically requires a scrubber to clean the air and if you use too much oil, the molding sand catches fire if you shake the molds out hot. Petrobond does not self mix like water with clay, so typically, when we used petrobond, it had to be run through a muller about every third or fourth time it was used, as you added new oil to replace that which burned off. The big advantage of petrobond is that you can make a mold and leave it overnight without worrying about it drying out. If you break off a section, it is easier to repair than water based molding sand.
A friend of mine has used sand for lead casting with some success however you can cast lead in a mold made of wood too... of course the wood mold could likely only be used once but it might be a simpler option. Thanks for watching.
I had considered the catlitter thing before doing this and decided against it. The reason is that while yes, clumping litter does contain bentonite -- it is chunky. The bentonite I purchased was ultra fine, like flour, which allows it to "coat" the grains of sand. I'm not sure that you could grind cat litter that well. If you try it please let us know the results! Thank you very much for watching and commenting.
Any advantage or disadvantage to having the sand like a powder? The obvious would be a smoother finish anything else that comes to mind?
Nice video. Would this mix work for casting lead? I'm trying to make some simple round wheel weights for a tractor out of car wheel balancing weights.
Thanks.
Many years ago we made 12 to 16 ounce "bell shaped" surf fishing weights from Padre Island. beach sand molds. That sand is a little too spherical to
cast much detail. We were using old recycled fishing weights and it is nearly
pure lead. One or two of per cent tin added can get you better mold fill-out.
Consult the Lyman Cast Bullet Handbook available at a library. Will you use steel clips?
can you reuse it once you have used it
Like how your camera figured out the lighting half way through.
I found a source of Bentonite. A well drilling company just a few miles away sells 50 pound bags of it for $17.50! I don't need 50 pounds, but if I haveto buy more to save some money, I will. Now I'm having trouble tracking down silica sand. The nearest Carquest to me is about 10 miles away, but I don't drive, so that's out of the question. Home Depot doesn't have the right stuff, too course. I'm looking at pool stores, filter sand might work.
what did you mix quartz sand and bentonite or something thank you?
Check the bag of your kitty litter. Most cheap ones are pure bentonite clay. Smaller applications you can grind it up pretty much which ever way. For larger batches, as the one here i'd say stick it in a cement mixer with a bunch of large steel bearing balls, and stick a lid over the top. It's going to be noisy as hell. Tilt the mixer to dump the lot through a screen to remove the balls, and start putting sand + bentonite back in to the mixer. Add water to consistency, and your done. Beats tarp.
Can you reuse this sand after molding ? I have already built my furnace.im lost on the sand. Can you please write a list of materials needed and where to buy from thanks
+Shawn P The advantage of sand bonded with clay and water is that it can be reused many times. The number of times depends a lot on what metal you are pouring. Aluminum is typically poured at 1300 degrees. That temperature will not burn out the clay. We use ours hundreds of times. Iron and brass pour at much hotter temperatures. Typically those production shops replace 10% of their sand each time they use it. The reason is that at the high temperatures that they pour at, Bentonite clay, which is an expanding clay, turns to Illite clay, which is not expanding. Non-expanding clays don't hold the sand together. Only the portion right next to the casting has the clay converted to illite, so you don't completely lose the strength after one pour. In a home foundry, you can keep adding a little clay as the sand gets weaker till you start to have permeability problems that manifest themselves a blows. Those are gas defects in the form of large holes in the casting or bubbles on the surface. Those can also come from just using sand that is too wet. I buy my clay from Carpenter Brothers in Muskegon, but other companies sell it as well. The sand should be one that is low in limestone or other particles. You want a clean silica sand if you are buying inexpensive sand. Often you can find it as play sand at building supply houses. It is typically well sorted and has very little clay in it. You can also use 2NS sand from a gravel pit. Fine sand produces a really nice finish on the casting but is not very forgiving if the sand is too wet. You end up with gas defects. Coarse sand is much more forgiving because the open permeability allows gas to escape through the pores of the sand at a higher rate than does fine sand. The disadvantage is that the casting is rougher. In the industry, aluminum shops typically use fine sand. Brass and iron shops use coarse sand.
I saw a video of a guy doing 10% cat litter and 90% finely grained sand to make good consistency... would that be cheaper than your material? It still does the job for "metal casting" if that is the intention lol
good job, but why not consider a ½" drill and a mixing paddle ... put all in a container from 5 to 25 gallons and whip it out in a matter of a minute or two? Good mix and complete water penetration is key, but the plastic process, although very clever, is also very time consuming ... keep it up, I learned a couple things and appreciate it@
Where did you get a pressure sprayer? (Online or Home Depot/WalMart?)
Don't know if they have a location in your vicinity but they sell bentonite at "ditch witch" retailers. I think it's fifty pound bags. We use it for priming concrete pump lines. Probably cheaper than getting it by mail.
o gotcha. since then i have just used play sand and it works just fine.. thanks very much for the tip of explosion
The sand you are using is awfully coarse for typical molding sand. You might want to get some 2NS sand from a concrete supply or gravel pit. The problem with gravel pit sand is that depending upon the state you are in, it might contain a lot of limestone, which will hurt the finish. If there is a foundry supply in the area, buy sand with an AFS grain fineness of 70 or finer. The higher the number, the finer the sand. I run a production and prototype foundry and we use an AFS 100 grain fineness sand. We have used AFS 400 sand in the past. When I was young, we would mix sand with an eastern coal shovel on a concrete floor.. Just place the sand and bentonite together and turn it over several times till it is well mixed. We always used a garden hose with a spray nozzle to wet the sand. Typically, you want to let the sand sit for an hour or so after you have cut / mixed it to allow the moisture to become more uniform throughout the sand. Mix the sand and water with a shovel. Store it in a plastic bucket with a lit to keep it from drying out. You can cleanup the sand with a broom when you are done. You didn't say if you bought southern or western bentonite. Typically, if you use rounded silica sand, you will want a mixture of 50/50 western and southern bentonite for aluminum. Western bentonite is stronger than southern bentonite. Too much western and the sand wants to stick together in hard lumps after you have poured your molds. We typically run our mixture at 7.5%, not 12% clay. That is a little high. More clay reduces the permeability of the sand, making it more likely that if the sand is a little too wet, you will get steam bubbles that will push through the metal as opposed to going out through the sand. These are called blows. If the sand is wet enough, it will rocket out of the sprue (the sprue is the hole that you pour the metal into the mold), something fairly dangerous. The sand should stick together like snow does, when you squeeze it. You should be able to take the squeezed sand with two fingers, and shake it lightly without if coming apart. If it crumbles, it is too dry. It should not stick to your hand. If it sticks to your hand, it is too wet.
You will find that the green sand would have worked much better if you had put the clay in a bucket with water and boiled it. This activates the clay. Otherwise, it will only slowly become active as you pour metal into the molds and the clay gets steamed. Over time the sand will nearly double in strength. With this level of clay and the strength it will achieve, it will be difficult to get a smooth casting without the sue of a fine screen (called a riddle) to break up the lumps as you put sand in your mold. You should use a riddle with 1/8" x 1/8" holes. You can order these from companies such as Freeman Supply and are known as a #8 riddle. The number is the number of wires per inch, or you can make your own with hardware wire screen.
I would be careful if you decide to use plaster. Plaster must be very dry before you pour it. Typically, you want to bake a plaster mold in an oven for at lease 8 hours at 600 degrees before pouring it, to get the moisture out. Failing to do this often results in aluminum foam as opposed to solid aluminum parts.
+cfjulian1225
Hello, thanks for your advice, may I ask, could you detail the boiling of the bentonite to activate it?
thanks... :)
+Julio says To activate bentonite, put it in boiling water for 5 minutes before using. The boiling water will hydrate the silicate layers. Once activated, you do not need to repeat this process, even if your sand drys out completely. The interstitial water will remain there. This activation makes the sand properly sticky. If you use bentonite sand that has not been activated, the sand will be weak until it has been used several times with metal having been poured into it. The steam activates the sand. In a production foundry, you typically add a little new sand on a regular basis. Since it is not a huge part of the whole, it doesn't significantly weaken the sand initially and it picks up strength as it gets used, from the steam generated in the pour. There are two types of bentonite. Southern and Western bentonite. I recommend western for anyone using natural sand and anyone not using a muller to process the sand. Western is much stronger than southern but if you pour aluminum in an automated system, the sand will stick together so well that it will be hard to push through a riddle and will load up on aerator fingers. By hand mixing, that is typically not a problem and as long as not mulled, it is easier to work with. We typically use 7 % by weight, bentonite to sand for hand molding. I typically use around 3% water in the mix. You can tell if the moisture is correct by grabbing a handful of sand and squeezing it. It should only barely stick to your hand and it you should be able to see the lines of your hand in the sand. When you take the piece that you just squeezed, you should be able to pick it up with two fingers and have it hold together. After you shakeout your molding sand, it is best to add the new water right away and then store it in a sealed plastic bucket. This will allow the water to spread evenly throughout the sand so that it works evenly when you use it again.
Hi cfjulian1225 I was afk for weekend, many thanks for the reply, I've yet to hear anyone speak of activation so I'm taking notes of all you advise... right now I've a tester pack ready, 1kg (1000gm) of Silica sand, 125gm of bentonite fresh from the blender.. also a mister of water.. oh and a kettle :D
Im ready to follow your steps with a sample batch, the ''boil before use'' still raises question, if I boil the clay, or add boiling water.. do I let it dry, then mix with sand etc?
Im thinking the wet clay wont mix, just want to do it correct, so if you could give me a step by step with the measurements im looking at, ill do it today, and get back to you :).. i really appreciate your tips and advice, thanks so much for sharing your experience in this science.. :)
+Julio says It would be best to let the clay dry out again before mixing it with the sand if you are using a mechanical mixer. If you are mixing by hand, depending upon the size of batch you make, you could activate the clay after mixing it with sand and adding water. The issue is that the clay needs to be steamed. If you have a metal garbage can, or and old drum, mix up the sand and clay with a little extra water then heat sand, clay and water in the drum over a fire till you see a good amount of steam coming out the top. Once you have steam going all the way through the sand and clay, the clay will activate itself. Let it all cool back down before you try to use it. If you are only mixing 1Kg, you could probably do it in a pan on a stove top. Be careful not to melt the pan. You can stir it to help distribute the heat.
o thanks much again i thought that was for seperating the two parts of the mold easily but he you learn something new everyday...
To get really good results with mixing,
put the prepared green sand into a 5 gallon bucket
with a tight fitting lid. Put the bucket in your clothes
dryer with the heat on the lowest setting possible.
put in some blankets, pillows, or cardboard boxes
to sort of keep it from damaging the bucket or dryer.
OR - if you gonna be doing a lot of this stuff, get an old
dryer and disconnect the heater.....
WaLa !!! a mulling machine
IF cat litter is pure bentonite, then it is easy access anywhere (even in Australia!) A good ball mill will do thejob of educing it into talc like powder
RE: Petrobond replacement, use the same mix as in the video, but use a synthetic 2 cycle oil instead of water. The oil I use is AMS Oil 100:1 seams to work very well. I just start adding 2 oz's at a time till I get close then a squirt oil can to finish. I'm building a small Muller to make things easier and faster.
how do you think this process would go in one of those small (electric powered) cement mixers?
Chris Peterson that would work, if you had one...if you don't, they are a little pricey to buy...you can pick up a tarp at the dollar store for 2 bucks.....or a tray (if you're making a small batch) for $4.00.
would this work to cast iron or steel?
10 bucks at a farmer's co-op will get you fifty pounds of super fine bentonite clay. Kitty litter is a pain in the butt to get ground down to a useful consistancy.
Very good advice. Done it too...it works well.
Is that calcium bentonite clay?
Thanks for posting.I am sure that you will find after mulling the mixture will give a lot better results. Good job as far as you have gone but the sand as shown is not there yet.The the devil is in the details and mulling is the thing you might find gives you much better results. The clay need to be pounded into the sand like you wouldn't believe just like Mr B says.
Everyone has to start somewhere! I agree..
Maybe the Box to type in should say "add a suggestion",instead of "add a comment"
The tarp method is very old school. How about using a bucket, a power drill and a mixing bit? Great demo but very time consuming.
Boris Sabo that would work too but I don't think you can get 50 lbs of sand into a bucket.....plus it is extremely dry so it might be hard to mix....I know I burned out a porter cable drill mixing mastic......(it wasn't a slow speed makita :-( I didn't have one at the time)
That makes sense, perhaps a cement mixer but that is much more expensive than a tarp. I will try your method, and thanks for the feedback!
Boris Sabo Not sure where you live, but I saw a small cement mixer at home depot...looked like it was about 5 gallons (it was about the size of one of those 5 gallon plastic buckets)....It actually would be the perfect size for these projects as well as home owners who had small jobs and had no need for the tow behind ones....
+Boris Sabo When you mix your sand initially, mix the dry sand with the dry clay. Boil the clay first, then let it dry out before doing this. Mixing in a bucket with a drill will not kill the motor if dry. Once the clay and sand are mixed, you can just spray the sand pile down with a garden hose and turn it over a few times with a shovel, then let it sit overnight. If you are using western bentonite, a light spray of water on top will leave a crust that protects the sand from drying out. Just push aside the dry stuff on top and use the stuff below. I typically just spray the top of the pile lightly before using it.
Nice explanation, however, I just don't get why you cut the bag like that :) in the bottom first and then a hook-cut so it flops open and just spills the internals.
Would it be better if he would turned the bag down side up,that way he would be cutting the top.
Buy your bentonite from a well driller. Probably cheaper. I got a 50lb bag for 12 bucks, and I didn't have any shipping costs.
It seems dry to me. Your mold will wash when you pour. I was a molder for years.
I am thinking of pouring aluminum in plaster of Paris.
Please let me know if you decide to use plaster. I would really like to know I helped.
Tried casting into plaster of paris early in my attempts. Terrible results. LOTS of bubbling...picture molten aluminum volcano lava...dangerous. My hypothesis is that the temp of the aluminum actually drove the water in the plaster crystal out and made mini (and not so mini) steam explosions.
Fred Landavazo IV I am not debating. Just making suggestions. Did you vent the risers? Maybe the plaster was not dry enough. I plan to try this one day and I will beware of your warning. Maybe bake in oven?
gypsum has a LOT of water bound up into it chemically; the heat of the molten metal is enough to break the bonds and drive the water out, even in a plaster casting that's completely "dried".....
a better option would be investment clay.....it's how they do lost wax castings with bronze & brass.(and gold & silver)....however, it's a single use type thing...the heat of the metal breaks down the material at a chemical level, so the mold would not be reusable.... A plaster mold will hold up to a couple of casts with something low temp like lead, but at the temps of aluminum, brass & bronze, molds just do not hold up.... there's a reason the industries use sand casting....
you can get modest results for brass and aluminum using wallboard mud as an investment, (coating a foam form), and then putting it in sand for support, but good quality fine-grained sand is going to be faster and more simply accomplished with fewer steps....
could use a small concrete mixer. that has worked well for me..
why is it called greensand?
The green sand moniker is because it has the correct moisture content, Why 'green' I don't know.
David Hunt So it is called green sand because it has the correct moisture content. sand because it is sand somehow and green for the fresh appearance?
TheElderScrollsKing
i believe its because properly mixed and tempered green sand will mold if left allone for a week or more turning green but heck if i know
The sand originally used for casting was naturally occurring. It forms in river beds and is a mixture of sand and natural clay . River bed sand has rounded grains from constant erosion by the moving water. These rounded grains maintain gaps between them even when compressed, allowing the mould to remain porous (as opposed to 'sharp' sands which tend to pack together more tightly) The green colour comes from minerals present in the clay.
Chris Johns Wow,thanks!
Why not use clay for casting?
Because with the Sand it lets the gasses through and if u used straight clay they gasses would get trapped and make bubbles in your cast. Hope this helps
God dam thats some good looking sand
Agreed. Don't shoot your mouth off and just put people's ideas in the garbage. Present your own, or shut your mouth :)
11:35 how do you move so quickly
+thebluemantis Meth and coffee has got him vibrating like crazy.xD
Another kind of sand you can use is pool filter sand.
+basement_sawyer Be careful of which pool filter sand you use. Don't use the stuff called diatomaceous earth. Although it is silica, it is the internal structure of a small critter called a diatom. This stuff collects in deep ocean areas with little other sediment being added. The disadvantage is that the spines easily break off and produce respirable silica. This dust will give you silicosis.
You can get bentonite at farm stores for 20 bucks for 50lbs
ALGUIEN SABE QUE MATERIALES SON ESTOS, GRACIAS, TANKS
The finer the sand, the less it will permit water to evaporate. This will cause explosions during casting.
use a mask or better yet a respirator when working with silica in any form
dust mask?... the silica in fine sand, dont know about bentonite
"i saw a video"... Dude,if you wanna sit there and grind up kitty litter.... good for you :)
I bought 50 lbs of sodium bentinite from a farm store for around 5 bucks
Kitty litter is clay, don't use fragrant type
RUclips seems to be full of spiteful people trolling to give thier nasty remarks
i am going to use recycled cat litter because i am green and AL gore said never wast and be a good little uneducated prius driver with a clean heart :}
yes sir go after it
شكرا جزيلا
11:35 is that a chipmunk on a pogo stick?
Nice vid..Sorry to burst Ur bubble,,The process you use is fine for the 1st 1/2,actually well detailed,But that silica sand is only 00 grade.So it does not matter how fine ur bentonite clay is.The surface finish will only be as fine/detailed as ur 00 silica sand.Bentonite clay is expensive as hell.Why not just use fire clay?It is less than $20 for 10kg ..You will then have change left to buy a sieve/riddle.I hope that white thing was NOT polystyrene,the thing U put the cope/drag UPSIDE down on??
well you do not have any videos so look whats you contribution to you tube other than negitory stuff
man thats fucking insane. call any local ceramics, pottery place supply place and they will have bentonite clay. usually they will sell it by the pound so you dont need to get a a freaking 50 dollar bag when you need six pounds of it. petrobond for sale website seems to be the ticket. guy is selling pre mulled petro bond for about a buck a pound shipped.
Wear a mask!!!!
RUclips seems to be full of a world of people with no training showing how to do it very wrong.