Hollow objects are very common in Asian jewelry designs. Indian
and Indonesian craftsworker generally leave a small hidden hole
to allow gases release. Thais on the other hand, are commonly
practicing, the rather dangerous, complete object sealing.
Sometimes even applying additional soldering cycles to the hollow
object without explosion!!
This is a very common practice in Thailand, called "PraKop". An
experienced "Prakoper" can easily solder a couple of hundred
objects a day!
Solder. - Use very easy flow solder.
Clean the suture by grinding using sandpaper. #150 will do just
I prefer to use wire solder cut into jump rings for round
objects. The rings should be just smaller than the object mouth.
By placing two rings, you should have a full cover of inner side
of the suture line.
I Use point pre-soldering along the suture for other shapes.
Immerse the entire object in flux and re-position the solder
rings. Apply quick heat to dry.
Heating - Experienced use of the torch is the key for successful
soldering. Operation should be quick and even. Use tweezers to
gently press the two parts together and lead the solder with the
flame along the suture. Apply extra flux to areas that hasn't
been sealed properly and reheat. Do not let the object to cool.
Keep heating gently while applying the extra flux. Experienced
workers usually reach complete sealing in only one heating cycle.
Cooling of the piece after soldering should be slow and
graduate. Never immerse the hot hollow in water. It is impossible
to reheat hollows that were quick-cooled.
Re-heating - Never re-heat object that had been cooled in water.
Do not pickle hollows. File it instead! Re-heating should be
graduate and done with extreme caution. It is an extremely
dangerous operation! You might considering drilling a hole to
allow gases escape.
Always wear your safety gear!!
Have a good day!
Dr. E. Aspler
Ganoksin Jewelry Co.,Ltd.