I wanted to share a successful soldering method for large silver
pieces. Noel's suggestion of using titanium "V"s for getting heat
underneath the piece got me thinking. Normally I use a heavy metal
screen that spans 5 inches between fire bricks. I know it was a big
heat sink but I have a big torch and it's what I've been using for
years. The problem was I was using boric acid for firescale and it
was building up on the screen along with carbon from the acetylene
torch. Occasionally a piece of carbon would find its way into the
silver and leave a pit.
So I decided to replace my screen with titanium wire. I called
Reactive metals and they recommended 12ga Ti. I use the Ti to span
the fire brick. I ran the wire 4 inches past the edge of the fire
brick then bent two 90 degree angles down so the each wire straddles
the brick and doesn't roll off plus acts as a counterweight to
prevent drooping when heated as Ti becomes ductile at 1500 degrees.
I still use boric acid and denature alcohol as fire scale
preventative. When a solder is complete the boric acid sticks the
piece to the Ti wire. After it cools a bit I dump the whole thing
into the pickle pot which cleans off the Ti wire for the next solder.
So I solved the buildup of flux and pitting in the silver and Ti
doesn't act as a heat sink. Thanks to Noel, Reactive metals, and the
Orchid community there is a lot less cursing around my shop and a lot
Silversmith and Lapidary Artisan
Colorado Springs, Colorado