[Elecraft] Re: OT: Removing Solder Through Plated Through Holes

[Don Wilhelm]

Mel,

Despite all the exotic methods, one thing is true - solder suckers of 
all types work much better when there is a lead in the hole to be 
de-soldered (the lead conducts heat through the hole).  Clearing the 
hole after the lead is removed is a different matter entirely.  For my 
part sticking something that solder will not adhere to into the hole 
(after heating the solder pad with a soldering iron) is quite 
effective.  A wooden toothpick will work, but I use a stainless steel 
needle.  I have several with handles than I have picked up at hamfests, 
but in a pinch a sewing needle with the eye end embedded into a cork 
works fine too (the needle will get hot, and the cork is only 'finger 
protection').

73,
Don W3FPR

Mel Farrer wrote:
> I would like to add a comment on removing solder from SMT via holes.  
> There are three methods and the first two have been discussed.  I have 
> found as the technology gets better, smaller, the plated through holes 
> also get really small.  Like 0.020 or smaller.  Solder suckers have a 
> very difficult time pulling the solder up.
>
> Let me explain, consider the mass of the solder pad on the side you 
> are going to apply heat.  If you get the solder liquid and don't 
> destroy the pad, the bottom pad, MAY be liquid and come up with the 
> sucker type.  It works good on larger pads but not so good as the 
> holes get smaller.  Too much air leakage and you are trying to pull 
> cold solder.  Not always successful.
>
> Using the solder braid has also the same problem as it is a heat sink 
> and usually requires you to put additional heat to suck the solder 
> up.  Works great on larger holes and traces that are large like 50 ohm 
> strip line. 
>
> OK, so what is left?  I use a solder "pusher".  Back before someone 
> invented the solder sucker, we used a small hollow rubber ball with a 
> small entrance teflon tube that we had and it had replaceable tips of 
> different sizes to accommodate hole size.  This allows exact pressure 
> of the right size on the hot side of the PCB and "blows" hot solder 
> out against the colder solder on the other side and effectively cleans 
> the hole without over heating the pad.........
>
> From someone who is long in the tooth,
>
> Mel K6KBE
>
>