Hey guys glad to be here. I’m in Southern Illinois and just getting started casting. I’ve got a 10kg Devil Forge that I’ve fired up twice now. Made a simple casting in kinetic sand just to finally do something with it. It’s not pretty but it’s functional, it’s a crank handle for my drill press table. I’m most interested in lost foam casting. I’ve been reading quite a bit but still have a lot to learn and haven’t even tried it yet. All in due time. Looks to be a wealth of experience and knowledge on here. Super glad to find this resource and great folks. Thanks
Welcome! There is lots of great info about lost foam casting here, look for posts by Al2O3 in particular. We're all going to want to see some pictures of that crank handle casting and your foundry equipment. Don't worry, nobody's first casting was ever pretty. Functional is great! Jeff
Thanks Jeff, I will definitely post a picture of it. I pieced the broken part together and pressed it into kinetic sand and poured the aluminum in. Ended up with a flat side but had enough extra metal to round out the flat side somewhat. Then I drilled a hole in it to slide over the output shaft from the drill press, drilled and tapped a hole for the set screw and it works lol. I have looked at a lot of Al2O3’s posts and YouTube videos. Great stuff, trying to soak it up. The only bad thing is I’ve fired my devil forge twice and already want to start a build on a low mass 8kw furnace . That along with the 50 other projects I’ve started.
Rocco, nice to meet you and that looks really nice for an early casting! What method did you use to cast yours? I’m gone at a track meet this evening, hopefully I can get a picture of my handle and the forge when I get home.
Green sand. I glued my broken plastic handle back together, filled the holes and hollow backside of the handle with bondo and used that as my pattern.
I did not know the use bondo as a core trick. Very cool, I would like to try green sand casting but need to aquire more tools for that.
The bondo was not used as a core. It was used on the pattern to fill the low or hollow spots so the pattern could be easily withdrawn from the sand.
Interesting. You guys are a wealth of knowledge here. Is that your go to method? Green sand casting that is?
Welcome Adam. I really like my resistive electric furnaces for a host of reasons but they are really only suited for metals with melting points of aluminum and lower, and perhaps some bronzes depending upon materials and construction of the furnace. If your primary focus is aluminum casting, your current furnace will take you a long way. If lost foam is of interest, you may be better served focusing your time on developing your foam pattern making skills first. Best, Kelly
Nice to meet you Kelly, and I appreciate that advice. I’m gonna keep the low mass furnace in my back pocket as a future project but you are totally right, need to get to pattern making and use what I have. Time spent with lost foam is my next best step. Btw while I’ve got you here, I just bought some shellac for laminating foam, but I take it as you’ve developed your process you prefer double side tape now for better burnout? If my part is say 4”, machine 2- 2” halves of a 4” part and then laminate them with thin double sided tape? I’m trying to stock up on materials as I work on learning my cnc router and Fusion 360 better. Working on a foam hot wire cutter now. Hope to get it built and then on to foam patterns. I still need to get you guys some pics. Hopefully this evening, first ugly cast, pyrometer build, and forge setup.
Here’s the first cast. In kinetic sand, just not quite setup yet for lost foam but getting there. There’s my pyrometer, I’m hoping the ceramic sheath will be here tomorrow. Anything I’m missing or need to keep in mind for this? Picked this up on Amazon. I liked the neck coverage and it was fairly inexpensive. I was thinking I maybe needed some spats also? Or are leather boots sufficient? I’m struggling to find sand but got this at Ace hardware. Gonna give it a try Working on a weir/pouring cup. It’s the ceramic fiber board. Should I coat the whole thing in pumpable fiber or just the seams and fillets in the corner? Getting closer…
Laminating is a bit of a challenge. The first is getting large areas to dry/cure. That's why I had used thinned shellac in a manner similar to contact cement, because the solvent was alcohol which didn't attack foam and would still evaporate. Two-sided tape is convenient, and there are others, but none of them will machine/cut/sand well. So, I always cut the pieces in layers and glue them together afterward. Lost foam sand is pretty forgiving as long as it is kept very dry, so it packs well with vibration. It's also helpful if it is a consistent mesh size. Pool sand should be high quality in these regards as long as you find it practical/economical enough for you. I used to buy this at the big box stores for $4-$5/bag. Sands used for mortars are usually higher quality. Just the fillet the corners/joints with the MCF so the molten metal doesn't penetrate and stick. The surface of the fiberboard should be non-wetting as is. It helps to have a little draft to remove the skin to ease in pealing out the frozen skin afterward with needle nose pliers. Keep the MCF on hand for minor patching/repairs/maintenance. Make a simple U-shaped cradle from a piece of sheet metal so you can grab it with pliers to extract and empty the cup while the metal is still molten. It will prevent damage from directly grabbing the cup. A contact pyrometer is an valuable tool. Not sure what the ceramic sheath material is but in my early attempts, my mullite sheath failed on the first dip due to thermal shock. I use carbon gouging rods as sheaths because they are resistant to this and thermally conductive so they respond fast. They eventually get consumed and need to be replaced, but you can buy them from McMaster Carr in 5pks for $1-2 each, but you must drill them to receive your thermocouple. Mifco sells coated thermocouples ready for use. If you search "contact pyrometer" or Mifco, or Mifco.com here you will get many hits. If you haven't already, take in this thread. It's a bit dated but still some good info in there for those starting out. Confessions of a Lost Foam Caster, 5 Years on. | The Home Foundry Best, Kelly
Thanks Kelly, that’s a wealth of info. The pool sand is right here in town but I’m sure by fall I won’t be able to get it so I’ll keep the mortar sand in mind. Can’t seem to find the quickcrete fine sand anywhere. Even online it seems to not be around anymore? And yes I’ve read that thread and need to read it again, great stuff! Here is the info on that sheath, I ordered it a few weeks ago before I found this forum. Now I’m thinking since ceramic is an insulator maybe it won’t be very responsive or slow to respond? High temperature resistant corundum ceramic tubes or ceramic thermocouple sleeves are suitable for various stoves and inserts. It is also widely used in electric power, metallurgy, mining, chemical industry and other industries. It is used to transport sand, stone, molten aluminum and other abrasive granular materials and corrosive media. Package Content: 1pcs x Stove Thermocouple Ceramic Cover; Total Size(IDxODxL): 6x10x400mm/0.24x0.39x15.75 inch; Material: 99 Porcelain Alumina
