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How to remove solder from plated-through holes?

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Alec_t

Jul 7, 2015
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I have a double-sided pcb with plated-through holes occupied by component legs. I removed a dead 16-pin DIL IC by chopping off its legs, then unsoldered the legs individually. Use of a solder sucker and solder wick has failed to clear the vacated holes. Any suggestions how to clear them so that I can insert a new IC? (I don't have an iron with the tip shape or heat capacity to solder 8 legs at a time, and I'm reluctant to drill out the solder).
 

sundy

Aug 5, 2016
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Apply flux it you have it, add solder to the holes till they fill completely. You are trying to make the solder clean and flow again. Try the solder sucker again, repeat til the holes are open enough, you might need to use the wick for touch up if the holes are really tight for the legs going through them.
 

Arouse1973

Adam
Dec 18, 2013
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Can you show us a picture? What iron are you using?
Adam
 

duke37

Jan 9, 2011
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You can get an iron with a hollow bit and a sucker action. This keeps the solder liquid during sucking.
 

Alec_t

Jul 7, 2015
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Tried the add-more-solder approach: no joy. The problem seems to be that with very small holes the solder's surface tension within the hole exceeds the capillary tension that the wick can provide or the sucker can overcome.
What iron are you using?
Tried a 25W with cylindrical tip and a 15W with chisel tip. Adjacent components prevent use of a larger iron.
Not sure if it is avail in UK?
Even RadioShack is unavailable in the UK :D.
Weller do a nice kit, but at £268 I think I'll give it a miss :eek:.
Thanks guys.
 

Arouse1973

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Dec 18, 2013
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I do this all the time. Have you tried to add some solder to the wick as your doing it? You cant do it dry all the time.
Adam
 

Minder

Apr 24, 2015
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Even RadioShack is unavailable in the UK :D.
.

They have pulled out of Canada also, But I got someone in the US to ship one to me.
Works pretty slick.
I think it was only around $25.00.
M.
 

Kiwi

Jan 28, 2013
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Didn't know there was such a thing as a desoldering iron. Might have to buy one as a Xmas present for myself?
 

dorke

Jun 20, 2015
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@Alec_t,
Sounds like you are doing things the wrong way!

1. A DIL chip doesn't have small holes ,they are large ,very large!

2. A 25W, and obviously a 15W iron are way too small for the job!

3. Never use a hand pump sucker it will most likely cause damage!

4. You need good quality iron (40W,chisel ),good braid and flux.
A dedicated combined single solder/sucker is the best way if you have one.

5. Apart from the VCC/GND pins, you should have absolutely no problem clearing the other holes.

6. You should watch this and learn !

7. There is another "dumb way" to clear holes:
Use a round needle-like tool, made of a material the solder "doesn't stick to" , like steel.
Heat the solder and insert the needle while constantly moving the needle ,it may work.
 

duke37

Jan 9, 2011
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The desoldering iron I have was obtained from CPC (Farnel). I have only used it once as I am bodging old valve equipment at the moment. I do not remember the price but it was a special offer so about £5.
 

davenn

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Sep 5, 2009
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1. A DIL chip doesn't have small holes ,they are large ,very large!

hahaha that made me laugh so much

if you think 0.5mm is very large

3. Never use a hand pump sucker it will most likely cause damage!


yeah, that I agree with .... they are dreadful and destroy pads and tracks with ease
 

(*steve*)

¡sǝpodᴉʇuɐ ǝɥʇ ɹɐǝɥd
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Jan 21, 2010
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Hand held manual solder suckers have their place.

I find them very good for doing what you want to do if you have at lest three hands and at least one eye that you can move to a different location.

The simple instructions are:

Hold the board vertically with one land and use your second hand and one of your eyes to guide the soldering iron to the pad.

Your third hand holds the solder sucker, and when your other eye sees the shoulder melt in the reverse side of the board you apply the sucker to the reverse side, remove the soldering iron and fire the sucker.

This works every time. Fortunately for me, I have an eye socket on the wrist of my third hand.

I assist a group of people doing public group soldering. Almost ask of them have two hands, and none want to pull an eye out.

I have come up with a cunning way to help these disabled people. I get one to hold the board and apply the iron while the second watches for the solder melting, tells person 1 to remove the iron before applying the sucker.

This technique works far better than trying to do it all from one side, does not fight gravity, and is remarkably effective.

If you don't have the hands and a portable eye, you can use a friend, a wife, or a girlfriend. Just don't ask all three!
 

Bluejets

Oct 5, 2014
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Now I know some are going to have a good laugh, but in some instances, (using the right iron heat of course) I have used the workshop compressor to blow out any stubborn holes.

Just keep your bare feet well clear though........:oops:
 

dorke

Jun 20, 2015
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hahaha that made me laugh so much

if you think 0.5mm is very large


For DIL packages 0.1"(2.54mm) pin spacing ,0.5mm is actually the width of the leg itself.
The hole diameter is about 0.7mm.
We have these Dinosaurs ICs for 50+ years,not a problem dealing with them.

In terms of nowadays PCB/device sizes, it is indeed considered very large.
via drill diameters go down to about 125um (5mil) !
If you compare it to 0.5mm spacing ICs, the 0.7mm(27.5mil) drill size is actually huge...;)

look here
 

dorke

Jun 20, 2015
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Now I know some are going to have a good laugh, but in some instances, (using the right iron heat of course) I have used the workshop compressor to blow out any stubborn holes.

Just keep your bare feet well clear though........:oops:

And,don't forget to have your pants on...;)
 

73's de Edd

Aug 21, 2015
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Sir Alec_t . . . . . . .

Ultra low tech / no big " munney" expended . . . . . solution :

Get a box of ROUND toothpicks . . .
Now . . . .in ye olden tymes they were typically made of hardwood . . .nowadays they are more apt to be turned down bamboo micro skewers. (So much more the better . . . . . for the durability aspect.)

Melt the solder in the via on the major foil side and insert one of your slimmest / slimmer tooth pick tips into the component /IC mount side of the via, while simultaneously rotating the toothhpick..
That . . . .repeated for " X " number of vias . . . . .should then leave all cleaned out and pre tinned vias, then being ready to accept the new IC.

73's de Edd
 
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Bluejets

Oct 5, 2014
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.
Melt the solder in the via on the major foil side and insert one of your slimmest / slimmer tooth pick tips into the component /IC mount side of the via ,while rotating.

Tried that once but ended up with the soldering iron lead wrapped around my neck and just couldn't seem to hit the hole each rotation.:D
 
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