24K gold leaf is thinner. (much) The foils traditionally used for
Kum-boo tend to be somewhere in the. 0006-.0010" range, while leaf
tends to be around.0002". (I wrote my masters thesis on a technique
that uses similar foils, so I measured a lot of them…)
I learned the technique from a Korean gradschool roommate of mine,
and he taught me how to roll the foil down the way they do it, which
gives a thicker foil.
Once in a blue moon, I teach workshops on Korean style damascening,
which uses the same foils. Part of the workshop is learning how to
roll your own foil, and how to evaluate it. The main difference with
working with the thicker foils is that they don’t diffuse away to
nothing as easily as the thinner commercial foils do. If you look at
a lot of the current literature (Celi Fago’s book, for example) she
talks about using several layers, and several passes to get different
’opacities’ of the foil. As you come back and do repeated heatings
with the thinner foil, it starts to diffuse to the point where it
just fades out. The thicker foils don’t do that. The drawback being
that you have to roll them yourself.
Just FYI, the foils that Allcraft has for kum-boo are .0003" for the
’normal’ and.0006" for the double-thick. I’ve taught classes with
them repeatedly, and always had good results. They’re expensive, but
probably less of a PITA than rolling your own for big stuff. It was
just that when I started, there wasn’t anywhere to buy foil, you
had to roll your own.