Keum-boo over Shibuishi

Hello people, A little help please. I’m trying to get 24Kt foil over
the japanese alloy Shibuishi with little luck. I’ve tried foil down
to 0.0025mm. but only got it to stick by using a caustic lead solder
flux. The piece to be overlayed is an inlay itself into a steel sword
guard, so its a pretrty big piece. All tests to date have been with
16 ga. shibuishi at 25 % silver. Any thoughts wouls be
appreciated. Regards, Mac

 Hello people, A little help please. I'm trying to get 24Kt foil
over the japanese alloy Shibuishi with little luck. <snip>

Mac, The problem seems to me to be one of metallurgy. The gold foil
should be bonded to fine silver and the high copper content of
shibuichi may be the source of your problems. If you want to bond the
gold by using a diffusion bonding process, you are going to need a
fine silver surface to attach the foil to. I can think of a couple of
possible ways of doing this:

  1. Use depletion gilding to bring up an area of fine silver. This
    involves heating, pickling, and brass brushing repeatedly for 4 or 5
    cycles. It may be a challenge to find a way to perform the process
    on only one area of the piece.

  2. Bond a piece of fine silver to the shibuichi first using a
    process similar to silver granulation. Once the fine silver is in
    place, bond the fine gold to the silver surface. You would need to
    have both the silver and gold foils cut to the exact same shape and
    have good alignment.

  3. Similar to number 2, but make some bi-metalic foil of fine silver
    and fine gold bonded together. Then attach the bi-metal foil, gold
    side up, to the shibuichi. I think this is the best approach.
    Although it may take some work to make the bi-metal and roll it out,
    it would be a one step process to attach it in it’s final form.

Just a few quick ideas. With a bit of experimentation, you should be
able to get it to work. Email me off list if I can be of further

Good Luck,
Jim DeRosa
James DeRosa, Jr.
140 Clifton Drive
Boardman, OH 44512-1616