I work in sterling and know that it is best to avoid gaps in
soldered joints. However I'm working on sort of free-form hollow
Chris, hollow items that you want to seal up can be a pain
sometimes. Most times the gap is caused by pressure from the inside
of the hollow form "pushing" the solder out of the way so the piece
can exhale. I have found these things to help...
I solder the piece as well as possible... then lay the part in a
burnout oven at about 175 deg. F. for 5 minutes or so with the hole
upward. This evaporates any internal moisture and helps stall off
the pressure escaping from the inside. When you take it out of the
oven...you have to work as fast as a cat to lay a touch more solder
over the gap and flow it. As always with silver, heat the entire
piece and start at the bottom when possible. This makes the actual
solder point heat faster. Sometimes one grade softer solder (lower
melt point) is better to use.
Take a Titanium solder pick, dip it in flux, DRY IT OFF.... and
while the solder is molten, drag it over the hole....
Ambidextrous??? It helps!
Use paste flux...which I hate...and VERY LITTLE OF IT. I
sometimes take Batterns, put it in a porcelain bowl and add enough
borax to make a paste. a thick paste...really thick. I then
sometimes let this dry until hard and break off pieces to use. Use a
porcelain bowl... NO METAL.
My favorite when I can.... Inside the ring, usually at the top of
the finger, I leave a tiny hole in the design. Sometimes round,
sometimes fancy. Chamfer the edges of this so it is smooth & beveled
so it will not irritate the finger. This will solve the problem
every time. Not all customer or designs let this happen...but I do
it when I can.
I had a customer one time that required about 75 of these blamed
hollow rings a month... we nearly went scrappies... that's Texan for
insane... figuring out what to do. These are the things we made
Good Luck! Dan