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comment by mk
mk  ·  1474 days ago  ·  link  ·    ·  parent  ·  post: Hubski Craft Fair v4.25 - April 6, 2020

I am jelly. I've always wanted to be able to "melt stuff". Can one pour into a plaster or clay mold?

You also reminded me of John's Grill in San Fran, and the amazing creamed spinach they have. Post-pandemic, I am getting a steak there.





tacocat  ·  1474 days ago  ·  link  ·  

Hell, you can pour into sand. I helped melt a lot of things in college but I try not to give casting advice on the internet because it's dangerous and I'm not an expert on the finer points. Wanna see an arrogant graduate student cause small explosions inside a large mold filmed with a potato?

kleinbl00  ·  1473 days ago  ·  link  ·  

"giant column of flame" is a good thing to avoid in casting. Some might even call it a warning sign.

There's a guy on Youtube going by "myfordboy" who is like the Bob Ross of casting. His shit is so zen to watch.

tacocat  ·  1473 days ago  ·  link  ·  

My professor was a "badass biker" who wanted to kill that guy for that stunt. And other things. I can hear him at the end. Even badass bikers sometimes lay awake at night worrying about a student getting a third degree burn and shutting down every iron foundry program in the country

I will check out your video when I get a chance. I like it when I force the YouTube algorithm to show me stuff like that for like a week

kleinbl00  ·  1473 days ago  ·  link  ·  

Yeah, foundry guys and machine shop guys have the stories that you don't wanna hear too much. half the machine shop stuff you can't watch because it trips Youtube's gore filter. Jewelers can't really compete but they can try; the kilns at my program didn't have peep holes because my instructor had someone in her grad program who peered through it while she shut the door, thereby puffing a couple liters of 1400 degree air right at her cornea.

Autoplay on myfordboy is like a japanese meditation.

kleinbl00  ·  1473 days ago  ·  link  ·  

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.