The Craftmans Shop > New from Old
Resurrection of a CFEI 100 KVA Induction Furnace
vtsteam:
I agree that the torch method for steel depends on oxygen to burn the steel and that isn't applicable for aluminum. But I was thinking a large welding torch rather than a cutting torch, and no excess oxygen to form aluminum oxide.
But I also agree that I think the Sawzall would be a better bet -- of course the right blade will also make a big difference there.
And then there's the good old wood fire outdoors and club..... caveman method. Quite effective and cheery on a winter's day. Just don't hit yourself with a bit of shrapnel.
awemawson:
I've decided to use an intermediate crucible when it comes to mould filling - pre-heat a crucible, fill it from the induction furnace, skim etc and pour.
So I need a pouring shank - all mine got given away. So make one - that was this mornings task.
1/2" Black bar perfectly adequate for these small crucibles but my blacksmiths hearth is not set up - how to heat it :scratch:. Not too convenient to use oxy-acetylene on long bars - although possible. Start off in the induction furnace - rapidly becomes impossible as the curve is formed. Shove it in the pottery kiln - ridiculously expensive in electricity.
Hang it - bend it cold!
So cutting an exact length of the bar to be the circumference at the height that I want the shank to sit, if I can get its ends pointing at each other and weld them firmly I should be able to bash it into a tolerable circle. It didn't come out too badly - be so much easier just to toss it in the hearth and do it hot, but you work with what you've got!
Once the ring was as good as it was going to be, I squashed it flat on the 60 ton press then welded a handle and a pivot - job done. The idea being that it will sit in a triangulated frame in front of the induction 'body' where I can tip the melt and do my stuff skimming etc.
Still need to work out how I'm going to pre-heat the crucible as I doubt that just putting it on top of the heating induction pot will be enough - damn the efficiency of induction melting !
mattinker:
Have you got a weed burner? They aren't very efficient, but I've seen them used as raku Kiln burners!
awemawson:
No Matthew - I did have but it's long gone.
But I had thoughts of resurrecting my Ceramic Chip Forge - not only could I have heated the ring up but it would do for pre-heating crucibles, and being gas powered with no coals, just ceramic chips, it's relatively quick to turn on and off. Currently in the depths of the tractor shed - I'll try and dig it out over the next few days.
vtsteam:
Looks good to me, Andrew.
I'm a cave man type so, if faced with that task, I would probably just build a wood fire outdoors from limbs I wanted to get rid of anyway, bring a couple of potatoes wrapped in foil, The steel goes in the glowing embers, and the potatoes go nearby in the cooler ashes.
Now I have a question re. ring shanks I've never seen answered -- and I've read a LOT of the available lit about casting and done a fair share it over the last 20 years myself. And that question is this:
How far up a crucible should the ring fit?
The reason I ask is because I have had crucibles slip out of the shank onto the mold when pouring the last of the melt. Not always but sometimes. And that is always an occasion for using words I'd prefer not to.
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