On , in ô Jack Schmidling wrote:

I can not find and am not ready to make a silver chalice of the sort I want
at a price that I can justify, at least for a practice piece. So, I am sort
of forced to consider plated brass or some other material.

From my experience so far with a plated pewter cup, the silver beads up and
the finding melted half way through the cup before I realized what was
happening. I was using a torch that was too big for the job and thought the
material was brass.


There are VAST differences between the three materials: Silver, pewter, or
brass. Silver stands out in that it is one of the best heat conductors there
is. The consequence of that is that soldering a joint without heating the whole
thing is often quite difficult. Normally, the proper method is to heat the
entire piece, not trying to isolate just the area being soldered. In addition
to assisting with solder flow, this also avoids some problems uneven heating can
cause with warping. With silver solders (real ones, not the tin/silver alloys),
because alloy materials dissipate a little into the parent metal each time the
solder is melted in a joint, and more, the longer it's held there, the solder
joints tend to raise their own melting point. With care, and the avoidance of
using too much solder, previous joints don't generally fall apart when doing
subsequent joints. heat sink compounds or simple things like painting a layer
of yellow ocher (essentially just dirt...) over previous joints also helps to
avoid such problems. With larger pieces, one needent always try to heat the
whole thing, but one still needs to generally heat a larger area than just the
joint in question.

Brass, while it can be soldered at close to the same temps as silver (not quite,
but close) is a much poorer heat conductor. So while heating just locally to
affect a joint is much easier, it also means uneven heating is much more likely
to cause distortion and warping. Also note that the addition of brass to silver
lowers it's melting point (It's how you make silver solder). So joining brass
with silver solder can be tricky, since there is a tendancy, as the silver
diffuses into the brass upon melting, for the amount of molten metal to quickly
increase beyond the original volume of silver solder. It can, as a result, be a
somewhat treacherous metal to silver solder, especially for beginners.

Pewter is essentially tin. So if you're soldering it, the appropriate solders
are indeed the tin/silver alloys, or tin/lead alloys if you prefer. Stay brite
brand works quite well. You can use an iron or a torch, but tin, even more than
brass, does not conduct heat easily, so a small torch can be easier to get heat
the the joint. the heat from an iron doesn't well travel beyond the contact
point. Very tiny flames, such as the little torch with a small tip, can be used
to good effect with pewter, and one can also easily weld it, just by melting
chips of pewter down into a seam, without added solder. Again, the
small/miniature torches work well. The smallest tip on a prestolite is also
very good for this work.. Pewter is also unique in that it does not work harden
with cold working. in fact, it actually gets solfter the more you work it. So
beginning work in holloware goes quite quickly with the pewter. Couple the
speed with which it can be formed, with the neat ability to shape forms by
techniques such as cutting "darts" out of the form, much like in sewing,
bringing the cut edges together (bending the form) and just welding it up again,
also greatly increases one's options. After welding, a little light hammering
of the weld to smooth it out and even up the thickness, and it can be totally
indistinquishable from the original metal.


From my experience with solder, one would have to get rather violent to
knock off a finding soldered this way. Surely, it or the stone would be
damaged before the joint would fail and it's gotta be better than super
glue.


The trouble experienced depends on the type of setting, and how one is setting
the stone itself. The pressures of pushing over and burnishing a bezel might
remove a small bezel soldered to silver with tin solder. The same bezel tin
soldered to pewter, though, would hold just fine. However, you probably, if
you're carefull, can use the low melting solders. It's just not as good a
joint, so be sure the item being soldered has sufficient surface area. you are
correct that super glues are not normally a decent option. But even this
statement can have it's exceptions. If, for example, the finding was a closed
back bezel cup, sanded quite flate after the stone was pre set in the cup, and
the chalice had a matched spot also flattened well, so there was a good fit over
a decent surface area, then perhaps super glue, or one of the higher tech
versions of the cyanoacrylate glues (some of which are used in assembling
aircraft wings, for example, so one knows they CAN be strong) would work well.
This would allow presetting the stones before affixing to the chalice, which
might offer some advantages. The joint strength likely wouldn't be as good, or
as long lasting, as solders, but much would depend on the preperation of the
joint, and the choice of the exact glue used. Some modern adhesives are amazing
things.

I noticed in a McMaster catalog some sort of heat
sink paste that I guess I could surround the setting with. Is this a
useful approach?

Sometimes. Not normally really needed, if the previous joints are done well.
If only the barely needed amount of solder is used, so that upon reheating the
part doesn't actually float on the solder, you'd find the part would normally
prefer to remain just where it is rather than moving or falling off.



the home of the Orchid mail list, a far busier discussion site for jewelry
makers........

Didn't notice the list.

The you missed the biggest gem of the ganoksin site. much, or most, of the
valuable info available on the site is in the archives of the orchid list
discussions. The mail list itself is very busy, getting normally in the range
of 50 posts per day. much more than rec.crafts.jewelry (good thing for me...)


Thanks but I presume aside from Ted, there might be other beginners
interested in the discussion.


there may well be, and it's public now. To be honest, my post was actually
intended to be a private email to you in the first place. hit the wrong
button....

Peter