Hello All:
Whenever you have to size a ring or solder an item with heat
sensitive stones that are far enough away from the solder joint,
you can protect the stones by the following method:
Do whatever you need to do to get the ring to the right size.
Pre-flux silver or gold items with boric and alcohol but don’t
burn it on, just let it dry. Platinum items need not be
pre-fluxed in this application since we will be holding the
stones under water. Put ring on
your third-arm tweezer. Fill a tuna can or crucible or the like
with water. Position the ring in the water so that the stones are
under water. The more of the shank that is above water the faster
the solder will flow. If the ring is open backed, I mean to say if
the stone or stones are visible to you through the back of the
ring, you will want to pack a small piece of toilet paper or Vigor
Therma-Guard, that cotton-like fibrous material that can be
soaked with water to insulate things from heat over the stone, to
protect it from the flame. Anyway, this will keep the fire from
licking the stone through the water. The pressure from the flame
can move the water away from the stone and cause the flame to
come into contact with the stone. Once this is set up, you flux
the seam and either place a chip of solder
on the seam or melt it on a charcoal block and pick it up with a
solder pick. I use a carbide soldering pick.
I solder using my usual propane/oxy on shanks up to about 2mm X
2mm in gold. On anything silver and gold larger than approximately
2x2mm, I switch my tank to Acetylene/Oxygen. On platinum I always
use propane/oxygen because the heat does not sink away as quickly
as with gold or silver. This is an excellent method to weld
platinum with stones set and keep from getting that dark seem
from using less than 1700 solder. It takes a little getting used
to, because the water will start to sizzle. The key is to be hot
enough to get it soldered in about 10 seconds. See how big a
flame you can make with your torch. Chances are if you do not
have an Acetylene/Oxygen set up you will have little success with
this method. Because the water is sinking the heat as fast as you
can provide it, the
flame must be bigger than your good sense would normally allow.
If you have a “little torch” use a #5 or #6 or #7 tip. Always
leave the ring in the water after you weld. Grab it with another
pair of tweezers and, without removing the stones from the water,
submerge the entire ring in the water until it is cool. If this
is impractical because the tweezer on your third arm is so hot
then, using another tweezer, dab water onto the third-arm tweezer
until it quits sizzling and is cool enough to touch. Usually on
silver I flow the solder on the outside of the shank first then
come from under the shank to pull it through.
I have tried all those cool jewel type products and this beats
them. Let me know if you need any more info.
Michael Mathews Victoria,Texas USA