Simple question about how to remove solder

Started by GuitarPlayer, May 17, 2009, 09:03:20 AM

Previous topic - Next topic

GuitarPlayer

How do you remove solder from a PCB hole?

I've had a couple of instances where I had to remove a failed component from my PCBs. The remaining solder refills that tiny hole, which makes inserting the replacement component a PITA  >:( There must be a method for cleaning out that hole.

Thanks in advance for suggestions / methods.

Jake

bassmannate

Well, the cheapest way to do is is get some desoldering braid. You just put it over the solder you want to remove and press down on the spot with the iron. Should be able to find a roll of this at Radio Shack for a couple bucks.

Perhaps the best way is to get a desoldering iron which is basically a soldering iron with a manually driven vacuum pump at the tip. You can also find these at Radio Shack where they have the regular soldering irons.

biggy boy

I run a drill bit through the hole again from the top.
I Use an Exacto knife handle that holds the drill bit.
the handle is the size and shape of a pencil.
Or you can use a solder sucker after you have heatedup the solder, I find it less occwerd to just drill the hole out again.
Or you could heat up that spot and push the new component in as the solder is melting.

Mark Hammer

+1 on the desolder braid.  I tend to dab a bit of liquid flux on the braid first, which effectively doubles its solder-removing capabilty.  Keep i mind that desolder braid IS, after all only bare copper.  And the same way that bare etched PCBs can get tarnished over time and not take solder very well,  can happen to desolder braid also.  Certainly store it somewhere airtight (or at least moisture-tight) when not in use, and "prime" it with flux when you use it.

Solder suckers are also useful for removing big blobs.  But once you have the big blob, getting rid of the last little bits to get down to a nice shiny smooth PCB pad will need braid.

Finally, I recommend keeping a bit of methyl hydrate on hand in a small bottle.  Once the solder is removed, you will have a bunch of unsightly flux residue around the desoldered area.  Dab a cottom-tipped applicator (Q-tip) in some of the methyl hydrate and rub the area to remove the residue and restore a nearly new smooth tinned surface.

petemoore

  Don't remove it, put the new part in through the hot solder, reflow the joint.
  Remove it by getting the pad hot, quick-whap the board on the edge of the table.
  Don't remove the resistor to make a smaller value, add one on top of the board.
  Don't remove the cap to make a smaller value if you can splice another in a wire.
  Solder suckers suck, I've never tried one. Braided solder wick works great, I've never tried that either.
Convention creates following, following creates convention.

Earthscum

Quote from: biggy boy on May 17, 2009, 09:13:28 AM
I run a drill bit through the hole again from the top.
I Use an Exacto knife handle that holds the drill bit.
the handle is the size and shape of a pencil.
Or you can use a solder sucker after you have heatedup the solder, I find it less occwerd to just drill the hole out again.
Or you could heat up that spot and push the new component in as the solder is melting.

I did the drill bit thing... problem I've found is that you will want to make sure you have the least amount of solder in the hole, or you could end up drilling yourself a new hole... btw, the handle I believe is sold as a "pin vise"... I have one that has a different size on each end that I use. Got it when I was a kid to drill holes for spark plug wires and stuff in plastic models. Also, another thought is that I have pushed pads off trying to re-drill through solder. That, quite obviously, makes for a very bad day. Also, on note of pads, I've jacked up pads simply by heating them too long trying to get solder to wick off (I was using twisted wire with the sheathing stripped... I didn't think of the flux idea first... that's awesome, and stupidly simple... I gotta try that on my copper tip cleaning pad)

The heating and pushing the part through is a trick I've been using lately on NEW projects... I'll get a pad primed with just a bit of solder to cover the hole, them insert my part with a heatsink pliers and then when I get a couple parts in, I go back and solder all the fresh joints and do a quick retouch to the tack job. As long as the other holes are cleared out, it could be advantageous to keep one of the holes plugged and heat it up as biggie said.

Personally, I'd try Mark's advice... just thought I'd throw my 2cents in. I've used denatured alcohol to remove flux with a q-tip... the particular board I cleaned apparently had an enameled coating as well, cuz that came off around where I cleaned.
Give a man Fuzz, and he'll jam for a day... teach a man how to make a Fuzz and he'll never jam again!

http://www.facebook.com/Earthscum

JFX09

Happiness is a effin' hot soldering iron