开云体育

I agree with Stephen. Use enough iron! If you use too small of an iron
you'll have to hold it on the board for too long while you wait for the
solder to heat up enough and melt and there's a good chance that you'll
overheat the board and cause the copper traces to lift. Also get a
temperature controlled soldering iron if you don't already have one. I
guarantee that it will make a marked improvement in your soldering
ability. And with a temperature controlled iron you almost can't use too
large of a soldering iron! If it fits, it will work!

Before you start make sure that the iron, the solder and the joint are
all as clean as possible! I use Kester 2% silver solder and it has a very
low melting point, 300F or so. It mixes with the original solder and lowers
the melting point so that I can quickly unsolder the joint and avoid any
chance of overheating the circuit board or the part. For unsoldering
something I set the iron at about 650 F and melt some of the solder onto
the tip of the soldering iron then apply the tip to the joint on the
non-component side of the circuit board. I already have my manual solder
sucker cleaned, cocked and ready to go. Once the solder on the joint is
thoroughly melted, not just the top melted, I use the solder sucker to pull
up the molten solder. If done correctly you shouldn't have to hold the iron
on the joint for perhaps two to three seconds and it will remove all of the
solder from the joint except for perhaps a very slight amount directly
between the lead and plated hole. I then use a small flat blade screwdriver
to push the lead sideways in the hole and break the lead free from the
plating if it's still attached. If I did the previous step correctly then
the lead is usually already completely free. It should take only a small
amount of force to break the lead free, don't force it. If it won't come
free then there's probably still solder on the reverse side of the board.
Only after I've checked and made sure that all of the leads on the part are
free do I lift the part away from the board. It should come free with no
force whatsoever. On double sided boards after you use the solder sucker,
you need to look at the reverse side and be sure that the solder there was
melted and removed as well. If it's not then you probably didn't wait long
enough after the solder started to melt to allow ALL of the solder (on both
sides of the board) to melt. If that's the case then you need to resolder
the joint and then desolder it all over again. I've never found any other
reasonable method of getting all of the solder off of the component side
other than resoldering and starting over again. I developed this method
while repairing circuit boards that could NOT be replaced at any cost and
that not damaging the boards was absolutely the top priority. Once I worked
out all of the materials and techniques it worked extremely well and I've
repaired thousands of boards using this method. FYI I've tried vacuum
operated solder suckers such as Pace brand but I still prefer one of the
manual ones. It's just easier to use even if I do have to manually cock it
each time. Keep the tip clean and pull the tip off every so often and clean
out the old solder inside of the sucker and regrease the piston and they'll
work on and on and on. I've acquired a few more of them as spares but I'm
still using one that I bought back in the 1970s. If it's operating
correctly, you can cock one then put your finger over to tip and then fire
it and the piston will back back part way but not all of the way due to the
vacuum inside of it and it will *hold* the vacuum.
I probably have or or have had at least one of every brand of soldering
iron out there and a wide variety of Pace and other soldering and
desoldering stations but I do most of my work using a regular Weller or
Hakko (929 IIRC) temperature controlled soldering iron and an antistatic
version of the Soldapullt solder sucker. I've also used the metal Paladin
solder suckers but for anything larger than a small joint I like the
Soldpullt because it's slightly larger and pulls more air. BUT, it's very
important IMO that you use a *top* quality solder such as Kester even when
unsoldering a joint. The Kester 2% silver loaded solder is hard to find and
is now stupidly expensive but it's by far the best solder that I've ever
used and I HOARD every bit of it that I can find and I use it very
sparingly. I won't waste my time trying to use lead free solder. FOR
ANYTHING!

I started out soldering, *and desoldering,* with a 200 Watt American
Beauty soldering iron with no temperature control. You should try that
sometime! I delaminated a lot of circuit cards!