On Sun, 17 Sep 2006 11:44:31 -0700, in rec.crafts.jewelry Carl 1 Lucky Texan
wrote:


I have no real experience with these issues, but in one of the previous
posts, someone mentioned the mill's roll diameter being a factor. maybe
Abrasha and other's experiences seem disparate due to large differences
in mill roll diameters?

The roll diameter has a minor effect on the degree of spreading. That would
make it difficult to do a very precise formula or chart, but not to the
difference in degree of spreading discussed in the thread. I think the
differences are due to most of us talking about rolling wire down to thin stock,
which is a very great reduction in thickness compared to the WIDTH of the stock,
while Ted's experience or discussion of rolling seems more related to what
happens when rolling wider stock such as a normal ingot, rather than wire.


Also, anyone know of a way the circles the OP needs could be
electrofomed? That might be an approach to the problem with some merit.

An interesting thought, though getting very uniform thickness might be a
problem, especially since edges might tend to be thicker. And the tooling for
the process might be tricky to think up. Also, electroforming karat gold
alloys to a consistant alloy composition is not easy to do. Usually, it
requires proprietary technology using rather sophisticated electrolytes, as well
as complex plating methods. Possibly things like multiple anodes of different
compositions, computer controlled with seperate power supplies, in order that
the deposition rate of the different metal constituents remains within the
alloy composition standards required. Remember that most gold plating solutions
produce a desired color range, but at essentially high karat gold, often around
23K or higher, even when the color looks like 14K or 18K etc. Getting an actual
lower karat deposit isn't so easy because the baser metals plate out at
different rates at any given voltage, so the bath composition changes over time,
changing the deposit composition along with it.

But it also brings to mind another option worth considering. while
electroforming to actually make the whole disk might be diffucult,
electroETCHING to punch the disks from sheet stock is certainly a very viable
idea. The process is very well suited to cutting precise shapes from thin
metal stock, and might be easier than punching given the thin stock. For gold,
it would work best, with a cyanide based etchant rather than acid, so safety
concerns would need to be met, but the process itself is not that complex. And
since electroetching would require very little clearance between adjacent disks
cut from flat stock, the waste would be less, though some of it would need to be
recovered from the etchant solution rather than remaining as easily melted scrap
metal. But that's not that hard to do either. Just electroplate it or "cement"
it back out again.

Peter