I'm resurrecting this 2016 thread from the AlloyAvenue Web Archive. See this thread if you want to do the same with other threads. I was only able to salvage 1 out of 4 pages. YMMV. http://forums.thehomefoundry.org/index.php?threads/photobucket.1798/#post-40134 Body - 100lb propane tank Crucible - Salamander A6 6.5" OD or possible A8 7.25" OD Refractory (Plicast 3100F KK) ID - 8.5" tapering to 7.5" Height - 10" Hotface thickness - 3/4" Floor - 2" thick Mating face - 14 3/8" OD x 2" thick Insulating Layer (IFB 2800F) 1+" Ceramic wool (2300F) 1" I picked up a 3D printer last year. Its been interesting discovering what it can do and can be used for. My goal in building a furnace was for lost PLA casting inspired by DavidF's work. Somewhere in the planning, I began wondering how much 3D printing could be used to build a furnace. Interior mold Exterior mold MDF framework and top hat mold Top hat lined with PETG sheet Wax coating (The wax and the tape caused surface defects) First segment cast and vibrated Second segment screwed down Cast and vibrated
I'm using a Makergear M2 with a build platform of 8x10x8" so I had to print the parts in pieces. All the parts could be optimized for thickness as I erred on the thick side. I visited re:3D this week to look at their Gigabot printers. The 24"x24"+ build platform is nice but I'd need to use their planned printing service. I can't justify the purchase price for my use. The interior form including the drain tube uses 1492g of Hatchbox PLA@$27/kg for a total $40. I would definitely use a 3D printer interior form again. I was pleased with ability to easily center the forms with the integrated tuyere. I'd really like to try printing a flame trainer form with a tilted tuyere next. I will need to burn these out to see the final result. The exterior form including the lid vent tube uses 1171g/$32. I wouldn't use 3D printing for this again. Disassembly was very easy but no easier than myfordboy's technique. I'll use MDF and plastic sheet next time. The outside turned out good. I'll have to wait until I cast the drain to see how the inside looks. Several lessons learned. There's water leaching at the mold seams - not alot but it affected the surface finish. The tape was not needed and caused a problem with the surface finish. The wax will complicate casting the drain. Lastly, I should have vibrated longer and used a wand. The lower section is much more bubble free than the top. A wand with longer vibrating would have helped.
The more 3D printing that I do, the more I'm convinced it's a viable shop tool instead of a gimmick. I made a run to Techshop in Austin early Saturday morning. If I lived closer to it, I'd never sleep. 25 hours of shop time later, I'm tired, sore, and happy. Vacuum forming the lid insert Took a few tries to get one that was smooth and released the form cleanly Propane tank is starting to look like a furnace With vacuum formed lid insert - almost ready to cast the lid. A few more 3D parts needed.
The lid was cast using a 3d printed center section and the vacuum formed forms. The interior surface was great - the exterior surface not so much. It was eventually covered by a fire brick donut and a welded cover. Painted with high temp engine paint. The furnace hot face is made of refractory surrounded by a collar and base of firebrick. It's meant to be removable if need be. Here you see it upside down. Again upside down and before the base is added. Inserted in the shell I'm using natural gas as fuel that's fed from a 1" line. Melting aluminum is very fast. I have not tried bronze yet. Air is supplied via a hair dryer which a since been upgraded to a bilge fan.
Nice work indeed, my only comment concerns the flame from the burner that looks as though it will strike directly impinging the crucible, I discovered the bottom of my first crucible badly abraided by the gas flow.
Thanks, the crucible is actually sat up 4 inches from the tuyere using a tall plinth. I tried a few flame trainer plinths but not sure it made a real difference.
