On Monday, March 29, 1999 4:00:00 AM UTC-4, DGoncz wrote:
I pounded out the inwardly curving bottom of an aluminum soda can until it was flush with the bottom. This was a can bottom cut to about an inch in length, most of the can was gone. I filled the recess with low melting alloy, and filled the opposing recess in another can. I pressed the cut off part onto the bottom of the can. I left the top in place during pressing to strengthen it. I cut the top off with a Swing Away can opener, which is the only one I have ever found to cut tops off aluminum cans reliably in one or two trips around the circumfrence.I put the assembly on the warming plate and the metal melted and was contained. I removed it from the warming plate and tried to figure out if the melting metal would keep a canful of coffee hot. The early result is no way. Apparently the conduction path into the can is not so good. So the impression that it takes a lot of time on the warming plate to melt the metal is not becuase the heat of fusion is that high. Also, there was probably an air bubble in the space, reducing heat transmssion further.Neat cup though. Real bottom heavy and when the metal sloshes around it makes neat sounds and has a funny feel. I ended up with a neatly cast slug.The outer surface of the bottom of such a can could be cast in wax and then in silver. A Peltier device could cool OR heat a can cup with that casting. The thermal conductivity of the low melting alloy just isn't right for the job. But I digress.These are preliminary results. There may be an organic substance that would do, and the false bottom could be assembled while immersed in a bath of such substance to eliminate the air bubble.I already have a stainless steel thermos mug. I am not sure it is evacuated. I got it at Goodwill. The combination of a phase change material and an evacuated shell is obvious. Would any of you like to try that one?I suppose I could pour the molten metal in the bottom of the mug, then never use it for food again. Probably better to dig into the junk pile for a glass Dewar, and smash it once a few certanties were found.The kids toy stores have a metal casting set that uses a low melting alloy. Yours,Doug Goncz Replikon Research, PO Box 4094, Seven Corners, VA 22044-0094 Please DO copy your reply to me via e-mail. http://users.aol.com/DGoncz or /ReplikonVA

OMG I don't remember doing this! It wasn't here at The Condo, it would have been at my first solo apartment, the one on Greenwood Drive, nearby. I can't remember a bit of it, but it sounds like something I would do.

Doug