Paste solders are convenient to use when you’ve got lots of joints to
solder & solder chips would be difficult to place or keep in position.
I make lots of chain &
paste solder makes solder application much easier & less time
consuming. Over 90% of the paste I use is for chain. For many other
jobs, sheet, wire or chips are still
my solder of choice. I even use chips on chain occasionally.
Soldering with paste does not negate the requirement for fire coating
or pickling. I’ve not had any problem pickling paste soldered items in
Precious metal paste solders are available in sterling & many karats
& colors of gold & gold filed. Some suppliers also provide several
types of paste for platinum. I know they’re available in Hard, Medium
& Easy melting temps. There may be other temps available, but I’ve
never used them or looked for them.
Most paste solders are composed of a powdered solder, flux & vehicle
that keeps the concoction semi liquid. I suspect the formulae vary
from manufacturer to manufacturer & from solder type to solder type.
Because of the paste (vehicle evaporates?) tends to dry over time, it
has a definite shelf life. Paste solders are usually supplied in
capped plastic syringes that are shipped with one or two changeable
dispensing needles. Most sterling solders are supplied in 1 oz, gold
in dwt (platinum?) syringes. It’s a good idea to remove the needle &
replace the cap when finished using the syringe.
Another solution is to make an ‘L’ shaped wire from to clean out &
plug each tip.
Each syringes is labeled & has the date of manufacturer on it. When
buying paste solder, ask for a syringe with the latest date of mfg.
When paste gets old, it tends to be difficult to extrude from the
syringe. If this happens all may not be lost. Paste solder usually
softens if warmed. Wrap the syringe (part with the solder in it) in a
wash cloth soaked in HOT water. Other options include placing the
syringe close to a 40-60 watt light bulb or blowing on it with a hair
drier. If either of these last 2 options are used, don’t get the
syringe too warm. Syringes are made of plastic & if they get too warm
may deform or melt, rendering them useless.
Most jewelers suppliers stock paste solder. It can also be ordered
from some of the national suppliers of precious metals. I get most of
my paste from my local jewelers
supplier. The sterling product they sell is made by Krohn Industries,
Carlstadt NJ. Many suppliers don’t stock gold or platinum pastes. They
can be ordered from precious metals suppliers.
Fluorides, cadmium &/or other dangerous compounds may be used in some
pastes. It’s a good idea to request an MSDS sheet for each paste
solder you desire to use & make a determination about it’s safety
before using it.
These comments are meant for the bench jeweler & designer. Large
jewelry manufacturers also use paste solders, but the method of paste
supply & techniques of
usage are apt to be different.