General Categories > Non Gun Stuff
Aluminum melting
unfy:
Crucible tongs / rod thing.
The concept was based off of the paint can furnace video I linked on first page. I've seen videos of other folks who use eye bolts and try to hook rod hooks through the eyebolts - but that never seemed all that great to me. Even in one of the videos, the guy only hooks one of the eyelets while on the other one the rod is hooked under *under* it and slips out later.
First pic is pretty much what I got now. I don't have the lower eyelet for hooking to lift the ass up to pour... but that's not the point.
The second pic is the same, but I horrendously drew on a suggestion of the bends I've talked about. With hooking from the inside of the crucible - if you attempt to tilt the crucible on the holder thing, you bump into the edge of crucible with the long straight part of the rod. I assume with the bends suggested, you wouldn't have to tilt the holder rod so far forward during a pour. Kinda needs more pics to explain, but.... maybe you get the idea.
Since I've gone through a few crucibles, perhaps time to discuss dross / detecting failed crucibles. Aluminum dross is far different than lead, mostly due to how light Al is and how rigid it cools to.
With the soda can source, the dross is fairly light, kinda 'burnt/expended wood' in a way. The Al doesn't necessarily just "fall through it" like lead does It will try to, but it's weight makes it not as forceful about it.
Due to the heat, it's got a weird texture, too. Kinda like a rubbery muffin. Or bread maybe. It's very light, very sproingy too.
When there's a huge blob of it down inside the crucible surrounded by molten Al and you're using spoon or something to get stuff out - it's got a very jello like look & feel.
When a crucible has failed, you've basically got a pot full of really hot dross. It kinda acts like the jello. When you try to press into it with spoon or whatever - it kinda acts like a wet stack of card board or a wet phone book. There's not a whole lot of give like there would be if it was floating on top of Al. Nor do you feel it kinda breaking up as you make it " V " as ya press into it (if it was in Al, that is).
Obviously there not being as much in the crucible as you think there ought to be is a no brainer :)
Al dross / flakes are quite sharp and can be surprisingly rigid. Just something to think about.
Lastly, and off topic. An ex-coworker came by, and we've both noted the smell of pineapple when melting cans. The sugar, maybe ? The cans in question are all soda cans. Pepsi, no name 'cola', and rootbeer.
I'll re-iterate that this furnace / crucible setup really prefers uncrushed cans.
unfy:
A second look at the crucible while explaining stuff to coworkers (who are interested as well)... we were all in agreement the failure was exacerbated by how I was grabbing the crucible with grill tongs etc. We'll work out a new system before the next melt.
The furnace and lid are very empty sounding. Kinda like old bread heh. And no, they don't have the 'earthen crucible' ringing sound to them.
I dunno if I posted this before or not, but the off center air inlet pipe really worked out well. It was definitely whipping the flames around the crucible with that 'swirl' folks talk about. So that's a huge suggestion / plus / change from the video. While other builds all suggest it, having actually seen it in action, I concur even with charcoal as a fuel source.
Heads up about the air gap. I was originally using a tiny blob of aluminum to hold the lid off the furnace for air movement. It melted heh.
And about the handles on the lid. It's obvious, but yeah - they get f'in hot! Everything was cooling for like 30-45min and the U bolts still burnt me when I tapped them.
unfy:
Sadly, the two crucibles from coworker won't work. He was in a rush... they don't even hold water.
I dunno if I'll attempt stuff Sunday or not.
In other news, was looking at the furnace and lid.
Lid's cracks seemed to have gotten worse. It also had a "feel" between pound cake and angel food cake. Decided to flex it gently just to see if I should even remotely trust it or not.
It crumbled heh. (first pic).
Looking at the pieces, there was a color difference between really hot and not hot areas. See the second pic. I post processed the picture just a tad to increase the color saturation a bit (the color difference is more pronounced than original picture showed).
Ran to menards, grabbed another plastic pot pan thing, and mixed up a new lid at 10PM heh. (last pic)
unfy:
Oh yeah.
Picked up some fire place tongs, a couple flat furniture braces (to run bolts through to make a stop point so i can't crush crucibles).
Also grabbed a 50lb bag of 'resco goldart' clay from the paint / ceramics place near 84th/78th and Harrison in La Vista. It was $20. It's prolly not quite what I want, but it'll do for experimenting probably.
As far as "what it can do", this seems to be a relevant page:
http://digitalfire.com/4sight/material/goldart_198.html
The above has an boogie woogie amount of cursory information about a lot of clays. I'd suggest a bookmark.
unfy:
Coworker redid the two crucibles.
Melting today.
Eyelets help a lot for control and stuff.
Not keeping count for can turn over etc.
Just a quick pic :).
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