Ron said:
Hi Chris,
I can only find GC 10-202 on the container. More accurately, it says
"Water Removable Soldering Paste" with "Solder Flux" written on top.
The directions state:
1). Apply Water Removable Soldering Paste
2). Heat
3). Then add GC's pure non-leaded solder
So, I'm guessing this is just a flux? But if that's the case, why do I
need to heat the paste first?
Thanks!
Hi, Ron. GC 10-0202 is a water cleanable, organic flux made to be used
with a lead-free solder. I'm not sure if GC Waldom still sells that
kind of solder. You can still use it with leaded solder, as long as it
either has no flux core, or has an organic (water soluble) flux core.
http://www.gcwaldom.com/catalog.html
Look on page 16 of the Chemicals section.
Flux is a good thing to have on the bench, because many times the
circuit board pad has become somewhat oxidized, or the component isn't
easily wettable for some reason. Also, extra flux usually means you
don't have to heat as long to get a good solder joint. The small
amount of flux in the solder wire core may not be enough to clean the
surface of the pad.
To use the flux manually, apply it to the circuit board or area to be
wetted. Apply the soldering iron to the area for a brief time to heat
up the flux (it becomes reactive at higher temperatures, and is
relatively inert at room temperature). You usually see it bubble, or a
small amount of smoke will come of the flux as it's heated. Then apply
the solder to the jointand release both the solder and iron as the
joint is formed. The flux cleans and chemically activates the metal
surface, making it more easily wettable by the solder. Otherwise, you
might just have a blob of solder sitting over a dirty pad or component
wire, with either poor or no electrical connection.
The advantage (such as it is) of organic water-soluble fluxes is, of
course, that the residue can be cleaned after soldering without using
banned solvents. This is something of an advantage, but organic fluxes
are less inert than rosin at room temperature, and can cause conductive
paths across the circuit board. Also, they can be kind of aggressive
at elevated temperatures, causing etching of traces under SMT
components that get hot. So, with organic water-soluble fluxes, you
really should make sure to clean the boards in water after you're done
(I like to use Palmolive Green in warm dishwater concentrations with a
brush, followed by a straight hot water rinse and warming oven dry).
Also, this is a water-soluble organic flux, so you should avoid mixing
it with rosin-based fluxes. Neither one works as well when they're
mixed, and you usually end up with something that doesn't work or clean
very well. Most wire solder has a flux core, so you should check
before you use it. If you want extra flux with a rosin core, use
GC-10-4202 liquid solder flux.
I hope this is the explanation you were looking for. If not, please
post again.
Chris
