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comment by kleinbl00
kleinbl00  ·  1452 days ago  ·  link  ·    ·  parent  ·  post: Hubski Craft Fair v4.25 - April 6, 2020

Melting stuff is easy. You need flame. Youtube thinks the way to melt stuff is put stuff in a stainless steel pan, put it on the stove and hit it with a blowtorch. Youtube is stupid. I'm fond of crappy Chinese melting furnaces that are ripoffs of crappy Italian melting furnaces that cost 4x as much. There are no non-crappy melting furnaces for less than $5k so the $250 one gets my vote.

The "and solidify it in an aesthetically-pleasing and mechanically-useful shape" is where the artistry comes in. What we're tooled up for is called investment casting. You start by making your thingy out of wax or, in this case, stereolithography resin that burns away without ash. You goop it with wax onto the end of the rubber cap shown on the bottom of this thing:

You then fill it with "investment" which is basically special plaster with some extremely fine porosity. You suck all the air out of it using this thing:

Then you pour the investment in, suck the air out of it again, let that harden and take the rubber bit off and put it in this thing:

You then program a "burnout schedule" that heats it up at the right speed to turn the resin into ash while leaving the investment magically delicious. Then after the 12 hours or whatever that takes you heat up your melter, add your metal, pull your drain plug back out, put it in the other hole of the casting machine, suck vacuum on it and add your metal. You let it stop glowing, then you pull the whole thing out and put it in a bucket of water, which causes a thermal shock to knock the plaster to bits.

That will be the next step.