Bi-metal & Enameling

    It comes in 18kt yellow gold on sterling, and 22kt. gold on
sterling.  They both only come in 20 and 24 gauge thickness.  The
max size they sell is 3" x 12".  I've used it for enameling.  You
have to be careful though.  If you fire it too many times it starts
separating.  Otherwise it's pretty cool. 

Poppy – I have never thought to use this for enameling before
(duh !!) altho I do a fair amount of enamel work. How often can you
fire before you have a problem?? Is it less expensive to work with
than foil if you want a gold underlay?? Have you used it with any
champsleve? My only experience with it was a number of years ago when
a fellow student burned off the gold while trying to solder; I hadn’t
really considered working with it since then.

Laura.
@LWiesler

Laura & Poppy, I, too, am an enamelist. In the last catalog from the
Enamelist Society’s juried exhibit “Crossing Boundaries” in Canada
(1998) is my piece titled “Dama” which is enameled sterling/copper
bi-metal from Reactive Metals. The piece is etched, rolled, hydraulic
pressed, then enameled. I found the bi-metal difficult to enamel, you
have to watch the kiln temp very carefully or you can get meltdown. If
you would like to see a scan of the piece, contact me
off-list. I’ve also enameled over Keum Boo. Donna in VA

Be aware that bimetal (i.e., 22k/SS, 24 ga) will often dish as it is
heated. As I understand it, this is because the gold and silver expand
at different rates under heat. Perhaps the layer of enamel that is
applied to the back of a piece would inhibit or prevent the dishing;
and maybe the Reactive Metals version of bi-metal is less subject to
this phenomenon than the Hauser and Miller; or that the controlled
temperatures of kiln firing counteract it. I’m not an enamelist so I
can’t say, but I have worked extensively with bi-metal in the past and
the curvature caused by the dishing presented quite a problem.

Beth

I have not tried the bi-metal for enameling. What i have used is a
heavy piece of 24K gold foil (rolled out myself, as I found the
foil sold for enameling much too thin) I apply the foil over FINE,
not sterling silver, and never have a problem. i fuse the gold on
the same way that I do a Keum Boo, except that by using fine silver
instead of sterling, I do not have to deplete the copper in order to
bring the fine silver to the surface. so far, I have had no problems
of separation, or the gold disappearing into the silver. I used to
fire clear flux on the silver, then apply the gold foil, which would
fuse to the flux. (the old traditional way of using foils).
However, I decided to try just fusing the foil directly to the
silver and it worked fine—held up up numerous firings.

Hope this is of interest. Alma

         i fuse  the gold on the same way that I  do a Keum Boo I
have had no problems of separation, or the gold  disappearing into
the silver I used to fire clear flux on the silver, then apply the
gold foil, which would fuse to the flux.  (the old traditional way
of  using foils). 

Okay – I have a question here – doesn’t gold, because it is more
dense than silver eventually sink into the silver and disappear (over
time?) – hence the need for using the flux under gold foil before
enameling? This was always my understanding. . . (also known to be
wrong in the past. . .)

Laura.
lwiesler@att.net

there are different thicknesses of gold foil. The gold used in
blowing glass beads is thinner than enameling gold foil. I tried using
some with enamels between a layer of flux and it dissapeared. I never
have problems with the enameling foil. Buy it from an enameling
supply, not a glass bead maker supply. I also tried the palladium foil
which also totally dissapeared. Good luck! susan knopp

Laura, yours is an interesting question and I don’t have any answer
as to whether or not gold applied over silver (keum boo), without a
layer of flux between the two would eventually sink into the silver.
You say “eventually” suggesting that you think it might be
something that would take place over a period of time, not
necessarily during the enameling process. This I can’t answer
except that my pieces–some over a year old have held up. I would
think that any changes would take place at the time the piece was
being enameled, and that once the piece is completed and not
subjected to any more heat, there would not be any further changes.
But you do raise an interesting question. I roll out my own 24 K
gold, so it is rather thick compared to the comercial gold, yet not
so thick that it cannot be fused to the silver. Perhaps the extra
thickness keeps it from sinking into the silver. I think if one
used multiple layers of the thinner commerical gold, this might help,
but again, I am just speculating.

Another point that might make a difference. I omit the flux between
the two layers only when I want to keep the weight of the piece
down, such as when making a pair of earrings. Also, I use this
process, only when I am applying a few layers of enamel—therefore
the piece is not being subjected to numerous firings. Also, I am
very careful not to overfire. Don’t know if this is why I have not
had a problem. Perhaps John Burgess can tell us whether or not the
gold will, over a period of time sink into the silver. - As I said,
interesting question you have raised Laura, and one I would like to
have the answer to as I’d hate to have this happen to a piece
sometime down the road… —cheers Alma

Gold will not “sink” or diffuse into Silver at normal ambient
temperatures . The temperature below which diffusion will not begin
to occur is approximately 1/2 the absolute temperature at the melting
point. for gold -silver this is about 600 C . At this temperature
the metals can diffuse but the rate is very very slow (years ?). As
the temperature is increased to the melting point the diffusion
rate goes up but it still takes time to diffuse until the melting
points are reached. Diffusion requires very clean surfaces in intimate
contact and inert surroundings to prevent oxide formation. This is
obvious when one observes how long gold plated , Vermeil , or
keumbo surfaces last at normal ambient temperatures- basically forever
if not abraded away.

Jesse