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

Been busy.

So a casting furnace uses about 1400W (1450 according to the kill-a-watt). An enameling kiln uses about 1600W. I don't know what the vacuum investment machine uses because 3000W/110V=27A which is more than household wiring or a 110V circuit breaker can handle so it's time to get medieval on it.

Fortunately we're in the garage and all the romex is surface in here anyway so we'll just continue a trend.

Pretty? No. Done in 3 hours? Yes.

There was a lull while I talked to my brother-in-law the electrician because those are 400A cables direct from the box with no way to turn things off. But the "mains", which are a pair of 30A breakers just sorta slapped in the middle of the box, do work as "mains" presuming you don't need to turn off the "furnace" (whose wires go nowhere ever since this place was switched from fuel oil) or "water heater" (which has long since been replaced with gas). So really what I've got is 60A service to the house, then unholy mother-of-god cables from the meter to the box, then I'm really only using half of the box which is okay 'cuz I've got like 12 slots to slap breakers in. But it was... dicey for a minute there.

MOAR POWWWWWAAAAAHHHHH

Worthy of note: I started with 100 feet of romex and this is what was left. Cut that shit close. Actually wouldn't have made it if I came through the bottom of the box rather than the top. So now I've got a handful of 12/2 scraps, 4 shiny new outlets, 3 shiny new circuits and a melting furnace I haven't used yet. Hmmmm....

So the way you make casting grain is by melting your shit, raising the flask to a reasonable height and then dropping molten whatever through water so that it turns to globules of glorious roundness before it hits the bottom, which is steel. Some of us have 1L vases.

I sent a picture of this to my buddy when he asked if I had a 20gal steel bucket. I sent him this said "no LOL but I'm bored." He responded with "be sure to film it because it's going to explode LOL"

"R U HAPPI NAU"

"Fill it up to the top"

So this is an after-shot because I'm not stupid enough to film molten metal with one hand and pour it with the other. Interesting discoveries: (1) Borax ignites in a burst of flame when you sprinkle it, causing you to spill (2) a carbon crucible raised to 1085c glows read-by-the-light-of-it orange (3) the difference between "not pouring" and "dumping immediately to the ground" is about 1 degree of tilt. But hey, when you're done?

114g of 99.95% copper! My buddy suggested that if I was feeling bold I could savage some old batteries for the zinc, melt it down and cast my own brass. I also didn't take any pictures of the excitement associated with savaging Costco AA batts for their zinc; suffice it to say that there was enough sparks, inadvertent heat and spitting electrolytes that I opted out. I did recall, however, that I had a fair amount of useless sterling scrap and my buddy has done a lot with shibuichi so let's melt some more stuff!

I'm prolly gonna calculate how much 90/10 shibuichi I can make with what I have on hand and get goofy with it. I figure this casting won't need supporting, has limited surface detail and will take on a wicked cool patina if I cook it right and what I'll be left with is an awesome little keychain-sized keepsake to embolden me before emarking on bigger, badder stuff.

'cuz the real problem is a principle consumable in 3D printing is 99% isopropyl alcohol. Since I don't know when that shit will be available again, I'm having to be creative but this one? This one I think I need to do.

Because reasons.





steve  ·  1452 days ago  ·  link  ·  

    I sent him this said "no LOL but I'm bored." He responded with "be sure to film it because it's going to explode LOL"

I cannot stop chuckling about this.

mk  ·  1452 days ago  ·  link  ·  

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  ·  1452 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  ·  1452 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  ·  1452 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  ·  1452 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  ·  1452 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.

Devac  ·  1452 days ago  ·  link  ·  

    My buddy suggested that if I was feeling bold I could savage some old batteries for the zinc, melt it down and cast my own brass.

I doubt you need anyone telling you that, but make sure to not disturb the surface too much once you get those two molten together. Zinc is crazy eager to oxidise in those conditions, which, once started, causes even more disturbances and splashing. Plus everything around it will be covered in that yellow crap.

kleinbl00  ·  1451 days ago  ·  link  ·  

Yeah I've kinda lost interest in savaging batteries.

I've got eight pounds of Zamak 2 but I'm not sure what to do with it. I'm told that it doesn't melt hot enough to thermally shock the investment so if I want to make a rock with a nickel center I should try treating this shit like bronze and see what happens.