Metal Casting - Lost PLA method

Matt, wait until you see what I did......its as printed but polished on the high sposts only. I think it its what we can both say "THATS IT!!!"

 

Matt, You and I both know how the pictures just dont cut it, but ill try.... ok how do you up load pics on this thing...Matt im sending pic to you, you handle it LOL

 

Matt, can you see it?? or need to see it in person? I can sort of see it, but I know what im looking at.....man looking at pics magnified does nothing for reality...

 

one have I must.....

 

Realllly want to get into casting and you're not helping those urges

 

For those who want to give this a try themselves... building a "small home hobby foundry" is very easy to do and not too expensive. You can cast all non-ferrous metals rather easily, tho most stick with aluminum or zink alloys. To build the foundry you need "refractory" which you can get at most pottery suppliers. That's the single most expensive part of the endeavour. I built mine out of a 6 gallon metal trashcan. You make a mold of our "burn chamber" out of wood and a 'column form' (the paper tubes used by construction folks to pour foundation piers) and put wood on both ends to support it and keep the refractory out. You will make a hole in the side of the tube to accept the burner once everything is done, and cut a hole in the side of the can. I used a piece of 2" ABS to form the "tunnel". I screwed a short piece of wooden dowel through the bottom of the can as a spacer, and this also allows the molten metal to have a path out in the case of a crucible failure. You then put 2-3" of refractory on the bottom up to the top of your dowel. Then screw the column form to the dowel through the bottom, seal up the top of your column form, and start packing in the sides. You'll fill 1" or so, then tamp down. Be sure to get good fill under the "burner tube" as well, as that can be a bit fiddly/tricky. Fill all the way to the top, then let sit for 24-36 hours before proceeding. While that's going on, do the lid. You'll cut a hole in the top for the vent. I used a tin can for the vent pattern spacing. Drill holes in the sides around the perimeter and "lace" support metal through in a grid. I used metal coat hanger. Then, you'll need some sort of handle... I took the handle from the top of the lid and screwed it onto the side. It allows enough purchase that I can grip it (with welders gloves on) to lift it off once everything is hot. I attached a set of bolts though the other side to allow for eventual bolting on of a bracket, but never did that... anyway! Once that's all formed up, again, fill and pack with refractory and let dry. After 36 hours it's time to burn it all in!!! You'll take your burner, I use propane, and slowly heat and let cool. Next time bring the temp up a little more, and let cool... repeat until you get to full temp (say 1600 degrees F and hold it there for 20-30 minutes. This process should take a day or three in all (depending on ambient and how thick your walls are) to fully cure the refractory. If you go too fast, you'll crack it. This can be repaired with a fireplace repair compound, but best to just avoid the issue all together and take your time here... For the burner, I made mine out of blackpipe couplers and some brass fittings. You need a high psi pressure regulator for the propane... most of the standard BBQ grill ones are too low and max out at 2-3 PSI. You need something more like 11 PSI (or more) to get enough heat quickly enough in the foundry... so you'll have to search around a bit! Then fit your couplers together, find a SMALL drill bit (forget the size, but it's one of the small letter drills) and drill the brass with a hold small enough to "shoot" down the burner. I made a crucible out of 4" steel pipe, a small 1/4" plate, a small piece of small blackpipe to work as a "pour handle" and some 1/2" nuts to to top so I could lift it out of the foundry once hot.

For the molding sand, you can use playsand you can get at any hardware store, and you'll need some "bentonite clay" which you can get either at the same place you get your refractory, or sometimes also at well drilling locations as it's used in the water well drilling process, or also maybe at a feed store as it's also used to line the bottom of stock ponds. Once of those three locations can get you pointed in the right direction tho if they don't have it themselves.

I think my whole setup was about $200, tho you could do it cheaper if necessary. I wanted larger capacity to do larger pours so went bigger than I required for a simple setup... For that matter you can use a cast iron pan and a campfire to melt aluminium, tho you'll have a weak part do to oxidation, if you coat the top of the melt with ash it helps and you just skim it off prior to pouring but you won't be able to deflux your melt prior to the pour... If you google around on "Dave Gingery" you'll find the plans and lots of folks who've gone down this path to great success. I've poured brass, bronze, aluminium, copper, and zink alloys. It's great fun and if you think being able to make parts outta plastic is awesome... use your printer as a way of fabricating patters (instead of lost) and start making anything!!!

 

i like to make this a hobby if not a part time job

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