There are two widely used precious bi-metals on the market today, as
far as I know. One is 1/20th 18k gold over sterling. This is a
material I developed and had manufactured for me in the mid 1980s
and then threw open to the field. It is made by Stern -Leach in
Attleboro, MA. and is still made to my original instructions. They
have large minimum orders so it is now distributed in smaller
quantities by Hauser and Miller in St. Louis. I don’t get a
commission or anything on this, which is fine with me. The material
is a recipe variation on gold filled (which is usually 1/20th 14k
over brass or other base metals). These proportions are by weight.
Since gold is heavier than silver the layer of the gold is therefore
less than 1/20 of the silver in thickness. How much less I will
leave to those of you inclined to do the math. It was most likely
manufactured by others before I reintroduced to our field. When I
was first trying to find someone to make it, I was told that they
did something like this during the copper shortages of World War II.
The other product is 1/8 22k gold over silver (I think it is
sterling but it might be fine silver). I assume this is also by
weight, since that is standard industry practice. The layer of gold
is much heavier in this product. As a result it is more expensive.
With that expense comes the beautiful color of that 22k and added
thickness of gold. This is made by Philip Baldwin, from the Seattle
area, for Reactive Metals.
Both products can be roller printed, soldered with a little care and
used for wide applications. Good stuff at a good price. On mine I
avoid hard silver solder and usually start with medium. Most of my
application is sweat soldered so the color is not to much of a
concern. I always use something to prevent fire scale (usually Prips
flux) since if you get blush in this gold you won’t be able to sand
it off. Since it is a thin layer, any abrasion should be limited. I
usually roller print textures on it and brass brush finish it.
Both products are also much heavier on the gold that any traditional
plating would be. They hold up very well.
In terms of stamping, my impression is that they should be stamped
1/20 18k/sterling and 1/8 22k/sterling. That said I have always
stamped my production line 18k and sterling. If you want to get
technical, you could do what some of the users have done and have a
special stamp made. Whether you do or not may depend on where and
how you market your work. In the JCK world, I would have the stamp
made, in the craft shows where I show, it doesn’t seem necessary to
two cents worth,