[sdiy] solder wick?

[ASSI]

On Friday 28 February 2003 21:32, Stephen Begin wrote:
> I've got a couple questions about desoldering
> Does anybody use the "no-clean" type of solder wick?
> What do you use to clean up the mess from normal solder wick?
> Is a cheap desoldering station worth having, or is it pointless
> unless you are willing to get a good one?

My summary on using solder wick: don't, unless you really have nothing 
else at hand (and then why bother with buying wick when just stripping 
mesh shield from a surplus cable gives you the same or better quality). 
I'm inclined to say the same about these plunger-type desoldering 
tools. It's far too easy to overheat the board or the part while using 
them and they just don't give consistent results.

Prepare a set of syringes of various diameters by leveling off the 
pointy end, they will last forever. You get the solder point wet and 
then just push the syringe over the wire and into the hole. Let it cool 
off while slightly turning and the wire is free. Go on to the next 
wire, if it's an IC make sure you don't overheat the package. This 
method has the advantage that you don't really need to clean off the 
old solder completely. You can still do it, I normally use a bead of 
solder on a larger iron to suck off the solder from the joint. To make 
sure the hole opens, I either use the syringe again or a wooden 
toothpick (make sure you have plenty around and a sharp knife to shape 
them if needed). For defective parts, I simply cut them off first 
(there are special cutters to cut cleanly right atop the surface of the 
board - well worth the extra buck). I even do this for IC that I need 
to rescue, it's easier on the part to be soldered to a socket after 
being cut off. I recommend to solder in sockets for IC's that had to be 
replaced, because unless both the board and the repair is top notch it 
won't stand another de-/re-soldering without damage.

If the board does not need to be saved, blow off the parts with a hot 
air gun (watch where the hot air goes and where you put your hands). 
Optionally pre-heat the board on a hot plate to 130-150°C, which might 
even save an FR4 board when blowing off with electronically controlled 
temperature.

For anything that is more then the occasional one or two parts repair, 
get a desoldering station with a vacuum pump. Whether you can live with 
a cheaper one (the really cheap ones are usually thrash from day one) 
is a question of how often you are going to use it and whether you 
leave it on for days. Usually the station can double function for a 
second (larger) iron that you may need anyway for the coarser work. 
Solder baths (around 50-200ml) are nice tools if you can get one cheap. 
I'm still dreaming of getting a small wave soldering repair station, 
but that is a bit over the top for DIY unless you have to deal with 
PGA. For anything like that, it is a good idea to look around in 
industry and ask professionals what they use. The bad craftsman blames 
his tools, the good invests in his tools.


Achim.
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