lost foam casting IMPROVED green sand technique - by VOGMAN
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- Опубликовано: 15 окт 2024
- Lost foam casting is typically done with dry sand but here I cast aluminium with Green Sand. Furthermore I share my improved sand casting techniques which have come about after research, experimentation and lengthy discussions with an experienced metallurgist and caster.
I’ve been able to refine my lost foam casting techniques to overcome issues such as folds to achieve a good standard casting every time, with improved metal flow giving a crisper finish.
For more information and updates to this video, see my website:
www.vegoilguy.co.uk/lost-foam-casting
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#LostFoamCasting
Just started messing with my first portable foundry and this video is helping relieve all my fears before officially casting aluminum. My first hairdryer didn’t have a cool setting so i had to shut it off before it was hot enough. Now that I bought a better model of hairdryer I stumbled across your videos helping me avoid common mistakes. The tin can candle paintbrush combo blew my mind and thanks for all your hard work!
Many thanks : )
Excellent video. I think these tips will really improve my lost foam casting. Thanks for taking the time to do this.
Many thanks : )
this is what I learned watching the experts,
1 you make the foam model ,
2 you dip the model in a light slurry of ceramic mixture this is important to get fine details, and let it dry well.
3 hold the dried model in a container
4 pour sand all over it to cover it well , (the sandbox was on a platform that shakes like a paint shaking machine) this allows sand to fill in evenly to all sides.
5 pour the metal of choice and voila a perfect precision cast.
Great videos! I've been struggling with casting and every time I screw one up I watch one of your videos to clam down and think about what went wrong its been very helpful.
Thanks David, that's nice to hear : )
Very nice explanation putting venting holes in the green sand to help release the gasses using a large to small riser and the same on the vent riser works really well
Thanks Perry : )
When making the sprue, you may make the cone, have a J shape or and L shape. This helps get the metal in at the bottom of the casting, so that way the gases go up the riser and don't fight the metal. The gear you had didn't really blend itself to the L or J shape, but other patterns would. You would have the metal enter at a low point. I've seen it on some the commercial videos. When I took metal casting a long time ago, I remember hearing this.
Thanx. You’ve answered many questions.
Thermal sleeves are available as Kalmin sleeves. I cannot recommend more the us of ceramic foam filters which a fit in the sleeve. ( forty odd years in aluminium and steel foundries.)
Great video. Just saw this. Excellent example (complicated pattern) of ‘make do’ lost foam, vibrating sand, vacuum using bike pump and light shell coating
I like keeping things simple if I can
Straight out of the mold... OUTSTANDING!
👍😎
many thanks 😁
New subscriber here and I am absolutely impressed. I am about to start a RUclips channel with a build of a replica 1928 Morgan RIP Killer MG Special 3 wheeler with 4 wheels. Charlie Martin raced it on a hillclimb in 2015 and I fell in love. The car was made exactly as if it were an airplane without a propeller or wings. It is a wood over steel frame with aircraft cloth stretched over the wood. It has a plasticizer just like the planes of that year. This particular one that seems to be the only one in existence has 4 wheels from a GN rear. I am using an opposed twin aircraft engine for the power plant in the front. Then I am casting a two piece adapter to mate this engine to the flywheel of an MG 4 speed transmission. Instead of the GN chain rear, I am using the MG differential with the beautiful black wire wheels. I have done a lot of thinking and figuring to determine the adapter from the PTO of the engine which will be one half in order to be able to bolt the other half first to the flywheel and then to the mating adapter. Otherwise it couldn't be done easily. I am so excited to start that I am actually giving away some of my other projects so I have room to do this build. Thank you for all the instruction. I feel more confident casting the parts instead of paying someone to make them out of billet. I believe the cast will work better because I can use really high quality aluminum from other castings.
this video is a slideshow presentation in and of itself! thanks a bunch
Many brilliant points, it's great that you have credit where it's due. Definitely going to subscribe to both of you. I have been casting for a while without the accuracy or detail to do much with the castings. After moving my shop and starting to get back into it I'm trying to get some casting projects going and will absorb all the information I can get. Excellent video
Many thanks. Happy casting : )
Great coverage of your techniques! Thanks!
Great video, I will definitely be putting some of these tips into practice. I have also had really great success with coating my foam part in a shell of plaster prior to placing it into sand. This eliminates the need for green sand, or even hard packing dry sand. The plaster holds the mold and metal in place, while insulating it to dry more slowly and evenly. You can still add the risers as you do, but encasing the foam part in plaster has been a huge help for me.
Hi Jason. Thanks for the kind words.
I actually tried plaster coating without success. Clearly you're doing something right and I'm doing something wrong. It was during my experiments with plaster that I first got in touch with Martin and he seemed to think plaster could make life difficult for gases to escape. That's why I gave up, but your words give me hope to try again : )
All the best.
Geoff
Brilliant! I'm following in your foot steps and have found that coating the edges of the cylinders with a wiping of mineral oil makes removing the plaster easy.
Hi Mike, That's great. Getting plaster from the moulds is the hardest part I've found. After that it's just benefits all the way : )
Great video!! I really appreciate the sense of humor and going into detail about how to improve the process, thanks. I really like the idea of the large plaster feeder, that's great.
Thanks Shawn : )
Yes!
Martin is the best on You Tube!
You'll get no argument from me : )
Very nice! I had one thought to look out for...making your plaster filler funnel out of several layers could pose a tisk of seoeration and dangerous spillage of molten metal. Maybe try a simgle pour or add wire between layers for integrity to avoid any accident.
When I was in the Navy the submarine tender I was on had a foundry on it. First off they kept the green sand at a very warm temp at all times and after packing the molds they would place them in an oven to bring them up to a higher temp before pouring. Of course they didn't use foam but solid patterns but preheating your sand would help.
Thanks Will. I have heard of guys putting there sand-filled-flasks in the kitchen oven - it must be the same sort of thing : )
cheers mate for the recommendation of olfoundry as he is in my neck of the woods.
When youre picking your foam , Theres some types of building foam insulation thats white with little blue dots . Dont use that , the blue dots are fire-retardant , and cause gas pockets . Also ,when Im doing long drawn out detail , I put a foam balloon at the points . Impurities turn into a gummy spot that causes an inclusion ,the balloon gives those a place to exit out of your casting .
Nice of you to drop that tip mate.
I've never done casting of this type, but I feel like an expert after watching your video. It was very informative, and very well planned and communicated.
That's very kind of you to say : )
Extruded foam is an excellent material for lost wax casting as it's so easy to shape. But it does take more energy to burn so preparing the foam well is helpful. Have a look at this video where I revisited the subject - ruclips.net/video/Bv1uV2MHMKk/видео.html . There'll be a link at the end of that to a aluminium wheel cast in this method and it demonstrates how precise and flawless home casting can be with just a little preparation.
So much useful information to digest, thanks for taking the time to do the research and make the video. I enjoyed it very much.
Thanks Lance. I've got a few more casting videos you might enjoy : )
For a finer finish than sand you can try dipping the foam in gypsum drywall compound that has been thinned slightly with water. allow for several thin coats to dry and then pour the part as normal in sand. I enjoyed your video and the tips. I will try them to improve my casts.
Great tip!
This channel deserve more subscribers than kings of random. This channel is pure science.
That's very kind but I think Grant Thompson left shoes so big I don't think they'll ever be filled : )
@@vogman you know im a fan of Grant Thomson. But your channel is very precise and in detail which is very difficult (to edit, script,v.o etc). Sir you're a hard-working guy respect to you 🙏🏻i wish i had found your channel before. And i liked the electric foundry series.and i was searching for a video of you using it in other projects.still finding.
There's loads of those my friend. Any of my recent casting videos and virtually every casting video back to the making of my electric furnace involve it in some way. I don't make a big deal about it, but it's there... quiet and dependable just as it should be : )
I've searched for days for the information you deliver here! Great video! Thank You!
Thanks Jonas : )
Thanks for that. I have a few projects in mind that would benefit from lost foam casting.
I will definitely try the plaster sprues & risers. If you want a fast set silicon putty, try mixing between 20 - 50% by volume, Corn flour with an acetyl cure sealant. (tile and bathroom sealant) The more flour you use, the firmer it sets, but in any case it goes off in about 10 minutes & is fully set in about 1 hour. You must wear gloves and work in an open area, because the acetic acid fumes are strong.
Thanks Mark : )
I really appreciate the time you've taken to do this. I want to make aluminum bronze knives and axes, and I want them to be as free of air bubbles and imperfections as possible. I was convinced using borax was the answer, but you've convinced me the mold itself is the most significant factor. I do wonder about your thoughts on borax, and if you've used it with any success?
Without a doubt, the mould is THE most important aspect. I'm still learning as my video this week shows.
I've very little experience with bronze so I can't really say... make few dabbles have all been porosity free, thankfully.
But if you're thinking in terms of bronze age, why not try the bronze age solution first? I understand the technique was to melt the bronze then throw in a pinch of dry charcoal dust.
I wonder if this works with lost polymer casting too ?
Can you lost wax cast in delft clay ? Delft clay is not absorbent and thus the wax should be able to run out ?
What about spray painting the wax with high temp paint first and then casting it in zinc ?
I want to find a cheap and easy way of casting undercuts without using the expensive and involved process of using invetment plaster and burn out cycles and all that stuff.
Man, there are some op notch tips here! Thanks for sharing
Glad you like them!
This is monumental! Thanks for doing this!
Any time!
Thanks for doing this. I hope to pour many knives and tools plus some other stuff with Aluminum Bronze and I appreciate you sharing your knowledge. Cheers from Texas.
Many thanks. There's a great Casting community here on RUclips so there's always plenty of advice and inspiration available : )
Very cool and helpful video.
Glad you liked it
I just wanted to thank you for making these videos. Well done Sir...
Thanks Nicholas. I appreciate that : )
Nicely done, thank you for taking the time to make this very helpful video.
A neat trick for creating a sprue fast is to place a funnel mouth down onto a smooth surface. Then place a suitable can, with the top and bottom removed, around it. Fill the can with sand, and ram. Lift up the can, and remove the funnel. Quick and easy.
Grate video. I have been at this for some time one of the most informative videos I have seen on the subject grate job.
That's very kind : )
Thanks for the video dude. I had so many questions about casting and your video answered them all and more.
Thanks Adam.
I'm still learning my friend and I enjoy experimenting & trying to find better / easier ways. I'm just building an electric foundry which I'll be sharing soon and then I have a few more techniques I'll be trying. Hopefully some of them will make things easier for at least some of my fellow amateurs : )
All the best,
Geoff
Excellent video and great compilation of techniques. Thank you so much for sharing the knowledge.
Thanks Nikolai. Happy to help : )
I have been a patternmaker for over 30 years and a lot of this has me scratching my head, but, bottom line, if it works for you it's good. Normally we cut drafted patterns with 0.010 inch per inch shrink. There is nothing left in the sand but a hole where a pattern used to be, and a metal filter etc. This is the best way. It is also the most expensive way involving several hundred thousand dollars in equipment and software. If you can figure out a way to get the pattern out before you cast it that's cool. If not pour away. I have some home projects to cast and my need to " do it right" has kept me from completing them. I actually have the furnace, equipment, and software to do it. Procrastination is a bad thing. I would keep doing it your way.
Cheers,
Hi William. Thanks for your input. It's great to hear from experts such as yourself.
I've known a few patternmakers and I have nothing but respect for the profession. Such degrees of skill and accuracy are way beyond my ham-fisted skills I think : )
I know what you mean about that void - that illusive empty space. The closest I can get is hollowed out foam. When I've finished my current foundry build I'm looking forward to experimenting with other techniques and strange ideas I have perculating. I doubt I'll ever match the precision of the professionals, but I enjoy the experimenting process and also enjoy sharing my findings. If it helps or entertains others along the way, then what more could anyone ask for.
Thanks again and all the best, Geoff.
Just starting out and I found your video very helpful, thanks for the detailed video
Happy to help Ryan : )
Waxing the foam that tip is priceless thanks
Yes, the wax really smooths things out nicely and you can work the wax to whatever level you like. It's possible to get perfectly flat castings without the foam texture if you apply the wax with care.
Thank you so much for your video. It is very interesting and well explained.
Many thanks : )
Very nice. I may try to make a few things. Thanks.
I warn you Brad, it's addictive fun : )
Thanks for the great video and the original research.
When I seen plaster I was thinking you would coat the foam pattern with plaster. I recall others doing it but not who. In terms of loosing heat, plaster should make sense for the pattern too. It might also give you the sort of detail you can get with lost wax and maybe not have to heat the aluminum. I don't fully understand it but pouring too hot can cause defects too.
Hi Dan. You're right - too hot is as bad as too cool in many ways, but I'm not really suggesting MASSIVE increases in temperature, just a bit hotter than normal. I seem to recall (I've read so much lately that most of it has fallen out of the other side) that factory lost foam castors were heating their metals 60 degrees higher than standard green sand temperatures.
Personally I don't have temperature monitoring equipment so such figures don't mean much to me, but it made me realise I needed to be a bit more patient... when I think I'm ready to pour I need to add the lid and let the temperature rise for a few minutes. And it does make a difference.
As for plaster encasement, there is potential there. I've done a few tests without great results yet. The issue there is gas entrapment. But I will continue to experiment and research. Maybe one day...
All the best
Geoff
Lost wax investment is supposed to pass more gas then plaster. Kerr satin cast is one brand. Excellent detail too.
It would be interesting to know how much gas is produced by vaporized wax.
Take a look a how the ceramic shell people deal with gas. Coating the model with wax is heading in that direction.
Thanks for that Dan. It's something I'll have to look at : )
In professional Lost Wax Casting the wax is melted out of the mold in a separate step before the casting is poured. Lost Wax Casting is the method by which bronze statues are made.
Wooh. Honest self criticism. You're a legend these days
Hi VOG, How about pre heating the sand before pouring the molten metal? Cheers
Very informative. Lots of good information. Thanks for sharing.
Glad to see you persevered with the comment I left on your other plaster casting video… about an hour ago... LOL!
Glad to see you got better restults! I've been looking at Martins channel as well. One obvious difference from Martins casting and your is that the feeder in Martins case is used as a resrvoir, a riser as he sometimes calls it. The narrower tube is the actual sprue through which the metal is poured. Is the reason for switching these around that you are using lost foam?
Maybe have a look at a channel called Makercise here on YT! He coats his foam patterns with plaster of paris and says he got better results!
Best regards
Karl
Good video. Martin is a treasure plaster risers should help green sand castings too. Metal in the risers could stay fluid longer so less shrinkage.
Exactly Dan. Thanks for watching : )
normally the drag which contains the pattern is made first on a flat surface then inverted and the cope created on top.
Cool matey very informative video , I will definitely use some of those techniques over on my channel as I need all the help I can get 😁👍🏻. I’ve chatted with Martin quite a few times and yes he’s definitely a casting God😀
Good to hear from a fellow Caster and RUclipsr : )
Yes, loads of respect for Martin. He's a really good guy, generous with his time and knowledge. He's a countryman of yours isn't he? Are you nearby or miles away?
VegOilGuy yeah mate we both Aussies unfortunately he’s 2000 miles east of me but if I went for a quick drive I could get there in 37 hours (as long as I didn’t stop to rest😳) yes he’s certainly great with his answering questions. I would love to get some of his casting sand off him that would be pretty cool as the cheapest petrobond in Australiacosts $40 for 750grams🙄. Anyway take care my friend be safe have a great weekend
You saying that, I remember watching a fabulous documentary about Aussie farmers. The Mrs would get up crack of dawn, grab the shopping list and head out to the local shops. She got back just a little before bed time having driven 1000 miles.
Don't worry, I'm not daft enough to believe all Aussies live like that, but I loved that documentary and how casual the farmers were about these amazing shopping trips.
Have you considered making your own green sand? There's lots of recipes out there... mainly involving cat litter. But you can buy bentonite clay easy email - it's used in beauty treatment. It's just a matter of LOTS of mixing then.
VegOilGuy yeah matey I have a little bit of bentonite clay powder I have mixed into half descent greensand but petrobond is like gold around here. I do have a couple kilos of petrobond which I’ll probably use to cast a nice dagger with very soon so hopefully I can salvage most of it when I’m done 👍🏻
Never tried petrobond. It seems fairly expensive in these parts as well, but I've been happy enough with green sand and mad experiments with blue foam.
I've been tempted to try the odd dagger myself, but I suspect my wife would leave me. There again, maybe I should : )
Just before my foundry decided to destroy itself after a gas hiccup mid firing we were using plastic straws every 3 inches as air release holes on large items, just a small bit of wood glue to hold them.
Also look up Jewelers plaster used in the making of rings etc better than just normal and cost more.
Also take all your used plaster and crush it up and mix with a new batch you get a stronger plaster.
Really useful video - thanks for making it for us.
Many thanks. I hope you look out for some more of my casting videos. I've refined things a little and gotten a bit better, as we all do with time and practice : )
good tips. i like look little pockets grove pack foam. allows know it lost foam casting. that said in side window computer there lost foam owl that looks super shine and smooth so i get that don't always want be ruff
I'm not sure if it was your vid or not, but the last casting vid I saw, I realized the mold needed more vents. no or too few vents the metal simply won't flow as well.
Good venting is important. It gets rid of the unwanted gases and aids flow : )
Brilliant! I'm still working on getting a usable piece. I believe this will help.
Thanks Chris. You'll get there. We all do in time : )
Great tutorial. Thanks. I've been kicking around ways to approach a part I want to cast. I may have found my approach in between the lines of your video. I want to cast a socket with a hole that passes all the way through the piece. You used plaster for your vent and gate. What if I made plaster inserts to creat a cavity and the passthrough hole, placed them in the foam model, and then into the sand? Then remove the plaster from the voids after casting?
I think the idea sounds a good one. But try mostly sand and just a bit of plaster. This is closer to traditional coring methods and will be strong, heat and (hopefully) crack resistant for you : )
@@vogman thanks so much. I will give it a try.
Awesome job thank you.
Thanks : )
Hey VOG I really enjoy your videos! that said I have a improvement to offer to you!
I am originally from the field of chemistry and started with metal casting recently. The first thing I thought about when I saw the lost foam casting method was: " WHY isn´t solvating the foam with acetone?"
If you pour some acetone in your mold you can easily remove all of the foam!! just flip it over and let the resulting slime drip out of the mold. Rinse the mold a second time with acetone dry it and you have a perfect mold for casting! (it should be noted that this only works with the plaster method)
mfg hazelChem
Very interesting 👌👍 I have decided to start buying the basics for lost wax. As I work with 999 pure silver. I know we had a brief chat, but I would appreciate your support to know the best budget starting accessories etc. Yes I will buy the bases from you. Lol 😆. No point 3d printing them. AceBullion®️ 🤜💥🤛
So much helpful information packed into a single tidy video! Thank you! Is there a video showing the sanded sprocket(cleaned up)? That I would love to see:)
Try this one... it's not the sprocket, but it is a support wheel that's nicely cleaned up : )
ruclips.net/video/ES1Xenom-e0/видео.html
oh man. What am I getting myself into lol. I will probably use a wooden cone to make the feeder cast and just cover it with polyester resin to waterproof it.
Thank you for sharing your expertise. Considerably better than watching so much of the gibberish on the topic.
Thanks Gerald. However, I have to admit I'm still learning. Like every other hobby and craft, we find different and hopefully better ways of doing things with more time and experience. You'll find a lot of videos on my channel devoted to making different things specifically to test and hone my abilities at casting : )
Nicely done
HI VOG. It's Damon here again, I went back to some of your old videos and pondered other casting techniques some of which you don't use and wondered if you have a good reason why you don't use them? Ceramic shell casting vs investment casting, investment casting vs petrobond sandcasting (without foam core)... also- I don't have a burnout oven for plaster investment casting and am toying with the idea of boiling out the wax- I have seen this for ceramic shell casting. Any thoughts on advantages/disadvantages of each method?
Ps I didn't mean boiling out wax for a plaster investment cast- I meant that for ceramic shell.
I've yet to try ceramic shell. I do like the look of it. For larger pieces I can really see the appeal.
As for other techniques, I still use Lost Foam if I'm making something large : )
Very, very cool. Yours by far is the most informative. I've watched alot of videos. You had all the info I needed, and at a pace that made it easy to make my notes. Again thanks. Ed in indy5
Thanks Ed : )
Try this video. I think it's the clearest I've done on the subject of Lost Foam casting - ruclips.net/video/ES1Xenom-e0/видео.html
6:30 Great tip thanks 👍
No problem 👍
Thank you. I will try to modify the Tips and see if I can use the technique on brass and aluminum casting.
As a dental techitian have casted frames and crowns fo ages, but with a centrifugal casting machine as what I do is small. A 3D scanner for larger parts and 3D printer or is there a foam/styrofoam milling mashine?
I've got access to a lot me tech these days... when I did this video, things were a little more basic. But they worked well 😁😁😁
Very nice!!
Bloody brilliant
Many thanks
Subscribed. Brilliant tutorial.
Many thanks. I have a few more casting tutorials planned after I've finished my electric indoor foundry : )
Fantastic! 👏🏾👏🏾👏🏾
Many thanks : )
have you tried refactory coatings to create a far smoother finish ?
Not yet, no 😁
Thank you
No worries : )
this looks good i would like to do this at my home
Good video
Glad you enjoyed
Love this video!
Many thanks : )
Hi Jeff, great video full of lots of interesting information, and like you I have had the pleasure of getting to know Olfoundryman [Martin], and hopefully soon I will be meeting with him for some one on one tutoring. We are both Melbourne boys. ;))
Hi Mark, that's fantastic. He's certainly generous with his time and his knowledge. A great bloke to know. I wish I could be there with you : )
Geoff
I was wondering if you might get just a touch jealous. ;))
Hopefully we might be able to make a video together, just to make for a slightly different format from Martin's usual ones.
That's a great idea. I look forward to seeing it.
And as for jealous... of the experience, the company, the activity... yeah! Completely jealous.
As for the temperature... no. If we hit the mid 20's here in the UK it's a warm summer and very hot is low 30's. Martin was telling me that mid 30's to 40's is not uncommon for you guys.
Still... cool beers a useful remedy : )
Which type of foam use for casting aluminum
nice video, very well done.
Thanks Ryan : )
seems to me you could make your plaster risers using a mold made from lost foam, eh? lol. put some hinges on it and seal the seams from the outside, not worrying about the flashing you'll have that you can easily take off. just want to make things faster, and since these wouldn't require a nice material you can just throw in some aluminum cans into the crucible and save the good stuff for projects.
Why do you use green sand instead of dry sand?
So what glue did you use ?
it must be noted there is 2 types of uhu glue ordinary and power, for normal applications they work the same, however uhu power is twice the price, in the pound shop the tubes of uhu power are half the size for the same money(a pound), uhu power can be used as an impact glue too.
Thanks Aly. I didn't realise that.
The trick is to test the adhesives and see which works best in a melting situation : )
Very informative, thanks. Maybe a more cost effective way to make those sprue's would be sodium silicate bonded sand. no need to bake off the moisture either.
Nice suggestion. Thanks : )
Have you made any stand-by plaster sprues for when your current one wears out or gets damaged? It could be handy to have at least one back-up in reserve for unexpected events. I was well pleased by your improvised wax melter. It's a clever idea. Are you familiar with Tubalcain/mrpete222/Lyle Peterson? He's a retired high school shop teacher who is pretty knowledgeable too. He's made hundreds of vids since 2006. If you don't want to bend up any more copper pipes when you remove them after molding, cross drill it near the top and insert a rod (or dulled nail) to use as a T handle. Keep up the good work. I really enjoy your vids and approaches to problem solving (I like to call it dragon slaying).
Hi Ron. That's not someone I've come across, no. But you can be sure I'll look him up : )
Great tutorial Martin. Question: how much detail you can get with this method? I need to make a custom aluminium heatsink, would the fins be too thin for the molten metal to get through?
Hi Juan. I think the fins of a heat sink would probably be too thin for aluminium. It might be possible, but not with home foundry equipment.
@@vogman I see, thanks
I'm no expert (especially at casting) but if you are after the wide shallow fins often seen on lower power electronics i'd think just green sand packed around a removable form would work fine. For the thin fins seen on most CPU and GPU heatsinks for example better off using a mill/lathe with thin cutting disk and sheet metal for fins- cut slits in the block preferable a touch narrow for your sheet metal so you can heat the block up to expand it a little and insert the fins. If the slots are a little wide then solder or thermal cement glue would be my suggestion. @@JuanSanchez-rb4qu
Thanks for the great video!!! Lots of good info and I got some resolutions to a few problems that I've been having. It's always the old guys who are the guru's with this kind of stuff, isn't it?
Sometimes I think and wonder if technology actually makes us better or lazy and uninformed, lol; I always think about that cartoon movie Wall.e .
But, then without technology, you wouldn't have been able to connect with your guru and pass your learnings from him on to all of us.
Why not burn off the foam before the pour. Or does this degrade the casting?
There's no need. It works great this way : )
theres not technically more gas due to conservation of matter but there is higher pressure and the foam is mobilized due to the gas state and pressure/temperature but I know what you meant. Just being pedantic for thoroughness thank you these projects are awesome.
What if you preheat the mold to remove foam and keep metal from cooling too quickly?
I haven't found it necessary, but feel free to try. Personally I've always felt that the "blast" from a torch will dislodge sand, spoiling the mold.
@@vogman what if you coat the foam in plaster before it is buried in sand?
Ah... you mean like this...? ruclips.net/video/Rg-NqEErlXE/видео.html
Have you played around with nighthawkinlight's starlite any? I think it might do well for this
can I ask a question about crucibles - I know steel degrades with use, but how does stainless steel stand up to use, ie. there are loads of balti bowls that are a decent size for next to nothing
Hi Colin, I'm going to be 100% honest - I don't have a clue : )
As long as the steel is quite thick (like a good quality saucepan thickness as a minimum) then give is a go. I'm intrigued by the idea myself and would really like to hear how you get on.
Best wishes,
Geoff
It'll fail also, I used a stainless steel cup that failed after 2 uses, any metal one will fail depending on number of uses and length of use.
could you dip the foam in liquid wax or would it deform?
Hi Alexi, I'd try it on a scrap piece first but I think it should work. Some waxes melt at quite a low temperature I believe, in the 30 to 50C range. I believe foam starts to distort in the mid 70s so there's potential there.
Give it a try and feel free to let me know how you get on.
Best wishes
Geoff
Thanks! Will do.
Why not make your little poke holes go all the way to the foam, venting will be improved and it’s easy enough to cut the resultant needles of cast metal off the main casting. Just a thought.
Very impressie
I am trying to make the thermostat cover of my old Daihatsu but I am having troubles with the curved form and its hollow inside.
A couple of thoughts spring to mind. Firstly, are you using a wire foam cutter (ruclips.net/video/jM2x_qaExc4/видео.html)?
Secondly, how about Extruded rather than Expanded foam? Extruded cuts, files and sands nicely and holds good detail. I talk about this a little more here I think - ruclips.net/video/Bv1uV2MHMKkH/видео.htmlope this helps : )
Did you have to break the plaster off the casting? If you use paste wax for cars or furniture on your MDF pattern, the silicon might not stick to it. That plaster feeder and vent look like very good ideas.
Hi Ron. Yes the plaster gets broken away in places. However sometimes part of the feeder survives and can be bonded to more plaster of Paris to make a new feeder. I'm always keen to re-use where I can.
Nice tip with the MDF. I'll remember that : )
🤓 BTW, I suspect that the black on your casting is soot from burning glue. It looks to me to be thickest near the places where your foam was glued.
There's a guy who put out a couple of casting videos, Brian Oltrogge, who made some extension for his sprues and vents that you may want to take a look at. They're similar to those that Myfordboy uses. Perhaps you could use his technique to cast your plaster extentions.
Thanks Ron. I'll have to take a look : )