Paste Solder

David Arens -

I’d greatly appreciate your comments on which paste solders you like
working with best and sources for them. I’ve long considered using
paste solder, but haven’t been much encouraged by what I’ve heard so
far. It sounds like you’re using it successfully.

thanks in advance -
ivy Fasko

Hi Ivy,

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
Sparex pickle.

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.


Ivy, I second Dave Arens comments on paste solder. If you are not
fusing chain links, paste solder is the way to go. One big plus for
paste solders, they do not ball up and roll away, or as snippets flow
away. they do a good job, just need to get used to it.

There is paste solder that is available in formulas that have
organic binders. these do not dry out. No need to have all that
fuss with a hairdryer, other flux, water etc. They are available in
many temperature flows and offer even more precise temperature
formulations than just hard, medium and soft. I have had one
syringe on my bench for over 2 years with no drying out. I could
use this tomorrow and find that it is every bit as viable as the
date it was put into the syringe. Beth Katz

Hi Beth,

There is paste solder that is available in formulas that have
organic binders.  these do not dry out. 

Sounds like the stuff to have!

Who makes it & where can we get it?


Dave, I have sent you email with the on the paste
solder. If anyone else is interested, please email me off list and I
will be happy to get the to you. If you do not like
attachments, please send snail mail address. As a point of
no additional flux is used when soldering as paste
solder contains flux already. Cheers and happy soldering. Beth Katz

Tom, The thinner to reconstitute your paste solder ( at least all
the ones I have used ) is mineral oil. It is available at most drug
stores. It will bring new life to your old dried up paste solder.
You definitely don’t want to add water to it. I know adding oil to a
solder is against all the logic we were taught about keeping solder
clean etc. but as far as I know, that’s what they use when they make
paste solder. The amount of oil you add will determine how thick or
thin the paste is. This is something you may want to play with, and
find out if one sort of consistency is right for your application.
Happy soldering. Don Friedlich