Teresa, I get silver paste solder in syringes from Hagstoz in Philly,
but have also gotten them from Rio.
Hagstoz’ phone is 800-922-1006.
Rio’s paste solder seems to no longer be sold in syringe form, but
is in jars.
However, in any case you could easily get appropriate syringes and
fill “as needed” from the jar – would probably keep a little better,
too. To get small syringes (without needles) cheaply (or for free),
check with your local veterinarian. They use them all the time for
vaccines and other relatively clean uses, and take the needles off
for medical waste discards. The syringes themselves are thrown away.
If you don’t mind cleaning them (take out the stopper and wash
thoroughly in a bath of hot water and soap, then lay in the sun to
dry), you’ll have a wonderful source in just the right size. If you
DO mind cleaning them, ask your vet if s/he will order some on your
behalf (they are ordered without needles) if you pay for them. Take a
look, but the 3ml size is probably ideal for most jewelry uses.
As long as the syringes are purchased without needles, they are
perfectly legal to have without a prescription. With the needles,
you need a prescription. (At least here in the U.S.)