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Paste solder

#1

The MSDS sheet for paste silver solder mgfd by Krohn Industries
Inc. indicates the following decomposition products: Boron
Trifloride (BF3), Hydrogen Floride (HF), Potasium Flouride (KF),
Boron Oxide (B2O3), carbon dioxide (CO2) & carbon monoxide (CO).

Special Protection Info
None for brazing in a properly ventilated
area. Properley Ventilated definition. Local Exhaust: Air flow to
produce velocity of 100 lineal ft/min in brazing zone.
Mechanical: 2000cu ft /min/brazer ie. 3 brazers= 6000cu ft/min
Natural: 10,000 cu ft space/ brazer- 16 ft ceiling with no
obstructions.

One way to help keep soldering (from any kind of soldering)
fumes away from you is by setting a muffin fan close to your
soldering area. Position it so it draws the air away from you.
Muffin fans donā€™t create a gale or a lot of noise. This technique
is used quite extensively in the electronics industry at
soldering benches.

Dave

#2

The MSDS sheet for paste silver solder mgfd by Krohn Industries
Inc. indicates the following decomposition products: Boron
Trifloride (BF3), Hydrogen Floride (HF), Potasium Flouride (KF),
Boron Oxide (B2O3), carbon dioxide (CO2) & carbon monoxide (CO).

Special Protection Info
None for brazing in a properly ventilated
area. Properley Ventilated definition. Local Exhaust: Air flow to
produce velocity of 100 lineal ft/min in brazing zone.
Mechanical: 2000cu ft /min/brazer ie. 3 brazers= 6000cu ft/min
Natural: 10,000 cu ft space/ brazer- 16 ft ceiling with no
obstructions.

One way to help keep soldering (from any kind of soldering)
fumes away from you is by setting a muffin fan close to your
soldering area. Position it so it draws the air away from you.
Muffin fans donā€™t create a gale or a lot of noise. This technique
is used quite extensively in the electronics industry at
soldering benches.

Dave

#3

Hi all,

I have just discovered paste solder and I love it!!. Alright, I
knew about it, but never tried it before. It is proving a godsend
for all the little bits and pieces I put together, but ā€“ why is
it so hard to push out of the syringe? Did I get some old stuff?
Should I be softening it up somehow before I use it, or am I just a
wimp?

Thanks,
Nancy

#4 
  Did I get some old stuff

i agree Nancy that fresh paste solder is often a blessing
ā€¦however I have often been plagued by deliveries of very stubborn
paste (old?) probablyā€¦from even reputable companiesā€¦let them
know of you dissatisfaction and returnā€¦you shouldnā€™t have to
tinker with it unless it became ancient on your partā€¦

Mosaic

#5

Nancy: I am also a paste solder user, and have noticed that it
takes a bit of pressure to get the solder out of the syringe. I
always attributed this dificulty to the fact the the paste is
quite viscous and is being forced through a small opening. Scott

#6

Paste solder flows very smoothly when fresh, less so as it ages.
It must be kept refrigerated when not being used, and has a
specified shelf life of only 6 months. If you are having difficulty
extruding it from the syringe, just scoop it out, cut it up and use
it as is. Or, you can thin it out a little with flux, to a
paste-like consistency, and apply it with a toothpick. Good luck.

#7 
      why is it so hard to push out of the syringe?  Did I get
some old stuff Should I be softening it up somehow before I use
it, or am I just a wimp?

I use alot of paste solder also (both sterling & gold). Generally
the liqiud (in addition to any liquid flux) used in paste solders
is glycerin e. With age &/or lower temperarure the combination of
liquids can stiffen a bit.

Two easy ways (there are others) to soften the paste & make it
easier to eject from the syringe, especially when using the 18 ga
needle, are: 1.Wrap the paste end of the syringe in a hot, wet
wash cloth; 2.Place the syringe close to a lighted light bulb
(40-60 watt) for a shor t time. Donā€™t forget it, too much heat from
the bulb may melt a hole in the syringe or cause it to deform.
Another way to make it easier, is to make a tool to help squeeze
the syringe. 1.Drill a 13/16 in (19.5mm) hole through a section of
1 in (25 mm) PVC pipe. 2.Cut the pipe off so it is about 2 in
(51mm) long & the hole is centered in the long dimension. 3.Cut the
pipe in half the long way so the holes are centered in each hal f.
4.Remove any sharp corners. 5.Insert the barrel of the syringe
through the hole from the concave side so the handles of the
syringe lay in the hollow of the ā€˜pipeā€™. 6.Place a 3/4 in (19mm)
PVC pipe cap over the plunger end of the syringe. Reducing the
height of the PVC plug to about 5/8 in (16mm) may make it mo re
convenient to use. Also putting a drop or two of PVC glue or nail
polish on the inside of the pipe plug will help to keep it from
falling off the plunger. 7.Squeeze the syringe in the usual manner.
(Syringe barrel between the ri ng & middle finger, plunger against
the heel of the hand; now squeeze.) Remove any mold marks and sharp
edges from the PVC. Depending on the size of the syringes you use
the dimensions listed here may have to be changed These
dimensions work for a syringe about 3/4 in (19mm) in diameter, with
a plunger top about 27/32 in (21.5mm) diameter. PVC pipe &
fittings can be cut easily with wood or metal working tools. P VC
pipe & fittings are inexpensive & available at most hardware stores
in th e US. When applying solder, better control of the needle can
be achieved if it is rested against a solder pick or similar tool.

HTH

Dave

#8

Hi Nancy, I have used paste solder in production work and found
it to be a great time saver. When you put it away or leave your
soldering station (youā€™re soldering with ventilation, right?) put
the cap back on and or put it in a zip-lock baggie. The plunger
side of the syringe can get a little dry too. You might try
warming the tube under a not too close lamp for a while. Have you
seen the foot pedal and regulator attachment? You hook it up to a
compressor and it allows you to deliver a measured amount of paste
with one tap of you foot. J.A.

#9 
I have just discovered paste solder and I love it!!.  Alright, I
knew about it, but never tried it before.  It is proving a godsend
for all the little bits and pieces I put together, but --   why is
it so hard to push out of the syringe?  Did I get some old stuff?
Should I be softening it up somehow before I use it, or am I just a
wimp?

Hi Nancy, Welcome to the club! I love this stuff, especially for
production, or any other large amounts of work, and I sometimes
work on thirty, one-of-a-kind pieces or more, at a pop. I havenā€™t
clipped solder for five years now, always hated those little
clippings. Fluxing, placing, flying, jumping, dropping, swearing,
and then having to look for the damn things with a lit torch in one
handā€¦Drove me nuts,(not that it was a far drive), and I was a
menace. Besides, clip solder seriously thwarted my impatience. Long
ago, I learned to chuck the syringe tips that come with the paste,
too dang annoying to mess with. The hard solder seems to be the
worst, it dries out and stiffens so quickly that those cute itty
bitty tips are less than useless inside of a day or so. Instead, I
squeeze out a bit of solder onto the tip of the syringe, and scrape
it off gently, directly onto the inside of the bezel before I place
the bezel, if thatā€™s what Iā€™m soldering. Or, I scrape some solder
off of the tip of the syringe with a sharp dental tool, and use the
tool to place the solder. Keep the syringe tip covered with the
white cap that comes with it to prevent drying when not in use. The
solder comes in hard, medium, easy, and extra easy, and can be
obtained from Frei and Borel among others. Pay LOTS of attention
to adequate ventilation while using this form of solder, flourides
are nasty nasty nasty. Good luck, Lisa

#10

easier way use a hair dryer to soften paste. Marty

#11

Re: old paste solder: Check the expiration date on the tube!
Sandra

#12

I donā€™t do production work, but I really love this paste stuff,
so how much are these foot pedal things? I have been keeping this
second set of syringes in a zip-loc, but did you see Davidā€™s post
about keeping it in the fridge?

Nancy

#13

Using paste solder , does it age in any other way as would make
unusable ? Could you ,after wetting it , put it back into a new
syringe ? and last question ,how does it compare to regular sheet
solder in cost ?. Oh by the way some reuseable vet syringes are
adjustable so as to put out a specific amount for each injection .
RLPowell, Texarkana Tx.

#14

To anyone out there, I just want to make some simple ā€œhammered
lookā€ earrings, is it as simple as getting some nice precut silver
shapes, and hammering, (what kind of hammer) and putting a jump
ring on amd earwire on, or is there more to it than that? (i know
zilch about metalwork) thanks in advanceā€¦

lynn

#15

Hi Nancyā€“I just recently discovered paste solder alsoā€“and like
it very much for the tiny bits and piecesā€“although it does have a
toxic type odor. I have been using a toothpick to take out a small
amount and dab it on the piece to be solderedā€“it works very well
and I donā€™t have to worry about squeezing out too much that I canā€™t
get back in the tube. Let me know if this works for you.
Sandra/ElegantBee

#16 
Another way to make it easier, is to make a tool to help squeeze
the syringe. 1.Drill a 13/16 in (19.5mm) hole through a section of
1 in (25 mm) PVC pipe. 2.Cut the pipe off so it is about 2 in
(51mm) long & the hole is centered in the long dimension. 3.Cut the
pipe in half the long way so the holes are centered in each hal f.

Dave,

PVC, duct tape and plexi glass sheet ā€“ I couldnā€™t function
without them! What a great idea for the plunger, Iā€™m sure I have
scraps of PVC in the box, but if not, Iā€™ll be on my way to hardware
store. Thanks for the tip!

Nancy

#17 
Paste solder flows very smoothly when fresh, less so as it ages.
It must be kept refrigerated when not being used, and has a
specified shelf life of only 6 months. If you are having difficulty
extruding it from the syringe, just scoop it out, cut it up and use
it as is. Or, you can thin it out a little with flux, to a
paste-like consistency, and apply it with a toothpick. Good luck.

Thank you, David!!

I did not know about keeping it in the fridge. It must have been
old when I got it because its been tough to get out since the day I
received it from supplier. Any recommendations for a good
supplier?

Nancy

#18

I did not know about keeping it in the fridge. It must have been
old when I got it because its been tough to get out since the day I
received it from supplier. Any recommendations for a good
supplier?

If you want fresh paste solder, just as when you want the freshest
fruits and vegetables, find a source that has a high volume
turnover. For gold paste solder Iā€™ve been happy with Hoover &
Strong, and for silver, Rio Grande. Buy the smallest
container/syringe that you esitmate youā€™ll use in six months or
less. Good luck.

#19 
Hi Nancy--I just recently discovered paste solder also--and like
it very much for the tiny bits and pieces--although it does have a
toxic type odor.

Sandra-

That odor contains fluorides. Nasty, nasty, nasty stuff! It will
do a real number on your lungs. If you can smell it you donā€™t
have adequate ventilation. Get an exhaust system in place or at
least a fan that pulls the fumes away from your face and out a
window. And wear a good mask.

This second set I got has started to work pretty smoothly. It may
be that it was dried out at the tip and now that that part is gone
its flowing okay. Great suggestions from everyone! Thank you.

Nancy

#20

Nancy, Did you accidently touch the tip of the syringe to the warm
piece of metal? That can harden the solder in the tip. What I do
is use a piece of small broken sawblade to unjam it or if that is
too big use the fine wire that binds the sawblades together. Be
careful, though, syringe solder isnā€™t very strong!! I like it for
things like repairing hollow rope chains and tacking heads into
place.

Wendy Newman
ggraphix@msn.com