I'd like to make a thin stainless steel, 60-degree, cylindrical cone with a small hole in the bottom; if it goes well it would become a conical fermenter for my homebrewing. 
I'm not particularly great at TIG yet though; usually I get there eventually, though its often not very pretty on thin material like this would be. Distortion is clearly going to be a challenge, and I'd also want to weld it from outside the cone yet have the inside of the weld as smart as possible (for sanitary reasons) - my limited experience of grinding back is that it creates inclusions and rusting on the surface even after pickling.
So, the fit needs to be 'very' good, and I could stitch-weld it to spread the heat, and back-purge too of course. But I was wondering if I should make some sort of aluminium back-bar as a heat sink, probably running the length of the seam and with a channel ground in it to direct the argon along the back of the seam. Does that sound useful, and/or any other ideas?
I was hoping to use stainless thin enough to roll up by hand, as I don't have slip-rolls or anything. But thicker stuff would be easier, so if anyone knows of a cheap way to make a cone in thicker stuff that could help too.
Asking a lot, I know...
Cheers
Kev

I'm not particularly great at TIG yet though; usually I get there eventually, though its often not very pretty on thin material like this would be. Distortion is clearly going to be a challenge, and I'd also want to weld it from outside the cone yet have the inside of the weld as smart as possible (for sanitary reasons) - my limited experience of grinding back is that it creates inclusions and rusting on the surface even after pickling.
So, the fit needs to be 'very' good, and I could stitch-weld it to spread the heat, and back-purge too of course. But I was wondering if I should make some sort of aluminium back-bar as a heat sink, probably running the length of the seam and with a channel ground in it to direct the argon along the back of the seam. Does that sound useful, and/or any other ideas?
I was hoping to use stainless thin enough to roll up by hand, as I don't have slip-rolls or anything. But thicker stuff would be easier, so if anyone knows of a cheap way to make a cone in thicker stuff that could help too.
Asking a lot, I know...
Cheers
Kev