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[Beginner's corner] Basic solder flow


#1

Flux - I have heard to put it were you will join the 2 pieces of
metal…then seen it spread all over both pieces of metal that are
being joined. Are there 2 purposes to flux…to help solder flow and
to protect the metal? If you spread it all over how does the solder
know were to go? I thought the solder just went to were the flux was.

Michelle
teka and zoe


#2
Are there 2 purposes to flux..to help solder flow and to protect
the metal? 

Yes, sort of. There are several types of fluxes. Some are
specifically intended to promote the ability of solder to flow. These
are more aggressive at dissolving existing oxides and cleaning the
metal. Others are more passive, mostly giving protection against
additional oxidation by blocking oxygen from the hot metal. But the
functions overlap. Many fluxes to both, at least to some degree.

If you spread it all over how does the solder know were to go? I
thought the solder just went to were the flux was. 

Solder flows by capillary attraction into a joint, by gravity
towards an area, and towards the hottest metal. Flux does not
specifically attract solder. What it does is to keep the metal clean
of oxides and other surface contaminants so that solder CAN flow. It
does not automatically flow where the flux is. But it won’t flow as
easily or at all if there is no flux on an area.


#3

Hello,

a short answer to this question is “heat”. You can draw or pull the
solder towards the hottest spot. It will flow in place and kind of
glue the ends together. Remember, it “acts” like a glue and is not
ment to be used as a “filler”. That’s why you need to file or saw
the two end as close as possible toward eachother.

I used the expression “acts”. The point is that the ends, soldered
together, should have a very small common layer of metal combined
wit the solder. This will give you a strong and reliable joint.

I hope that I explained this good enough. Anyway, flux will not
garantee that the solder will flow. the metals need to be clean. Do
it step by step and create a routine. After some time, you will be
able to solder within seconds if you do it the way it has to be done!
Anybody can do this but most craftsmen start of with the wrong
procedure and keep on making the same mistake(s)

have fun en enjoy
Pedro