Author Topic: Problem with removing solder...clearing pin.  (Read 1948 times)

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Offline cepwinTopic starter

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Problem with removing solder...clearing pin.
« on: January 01, 2019, 12:59:53 am »
I'm building a kit and ran into an issue.   Basically I placed an LED too high  and tried first to reheat the joint and pull it down...no success and after trying that I did something that was likely stupid and decided to snip it off as I had plenty off lead and figured it would be easier to remove the solder and reseat it.   Well, I managed to clear one hole but no mater what I do I can not remove the solder and clear the other hole.
Details:
1. I'm using lead-free solder at 398c ~755f
2. I've tried the techniques I know like a solder sucker and solder wick and very little is coming up...the solder sucker seems useless.

picture attached:
 

Offline ataradov

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Re: Problem with removing solder...clearing pin.
« Reply #1 on: January 01, 2019, 01:18:50 am »
It looks like you are not using any flux. That would be the first issue.

Then try to just use a sharpened toothpick and clear the hole using that. Melt the solder (add more solder, it will actually help), then quickly push the toothpick though the hole.

Also, the soldering on the first hole was not great to begin with. You really need flux.
Alex
 

Offline Brumby

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Re: Problem with removing solder...clearing pin.
« Reply #2 on: January 01, 2019, 01:25:30 am »
Yes, adding more solder often helps - with solder suckers too - but the toothpick approach will be much easier when you only have the single hole to worry about.

... and extra flux is rarely a bad idea.
 

Offline cepwinTopic starter

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Re: Problem with removing solder...clearing pin.
« Reply #3 on: January 01, 2019, 01:41:04 am »
Thank you so much for your suggestions!!   Ironically I just ordered a flux pen today and if I don't have toothpics I'll pick some up.

Thanks again!!!
 

Offline admiralk

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Re: Problem with removing solder...clearing pin.
« Reply #4 on: January 01, 2019, 01:48:54 am »
Instead of a toothpick, why not just use the new LED? Sure, you can only go so far before you have to line up the cathode, but...
 

Offline cepwinTopic starter

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Re: Problem with removing solder...clearing pin.
« Reply #5 on: January 01, 2019, 02:08:33 am »
Yes Thanks!   I actually used lead snippings to verify that the one lead was clean and help clear it once I got most of the solder away.  Did nothing for the other but I didn't have any flux (as I mentioned it's on order.)   I'm actually going to test the original LED because it may be fine and no need to replace it with another.  I should have enough lead to get it correct.
 

Offline Kasper

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Re: Problem with removing solder...clearing pin.
« Reply #6 on: January 01, 2019, 03:30:52 am »
Add solder, add flux, use lots of good wick and repeat. Try working from both sides also.

If there is a pin in the hole you are wicking, try wiggling the pin sideways with the iron while wicking. Sometimes the hole is almost fully wicked but the pin is stuck to the side of the hole and there is little solder holding it to the wall. You can sometimes wiggle it loose but be gentle.
 

Offline David Hess

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Re: Problem with removing solder...clearing pin.
« Reply #7 on: January 01, 2019, 03:34:26 am »
In extreme cases I use drill bit smaller than the hole diameter and a pin vice to drill out the solder.  Heating and pushing a stainless steel needle through is suppose to work well also.
« Last Edit: January 01, 2019, 06:02:45 am by David Hess »
 

Offline Brumby

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Re: Problem with removing solder...clearing pin.
« Reply #8 on: January 01, 2019, 03:56:55 am »
Whatever alternatives you try - just be careful to not overheat the area.  Lifting pads or tracks is really annoying.

And, obviously, don't get too physical or you could damage things too.
 

Offline helius

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Re: Problem with removing solder...clearing pin.
« Reply #9 on: January 01, 2019, 04:52:35 am »
These are helpful tools for stuck pins:
https://www.ebay.com/itm/8pc-in-Set-Hollow-needles-desoldering-tool-electronic-components-Stainless-steel/262665800592

Solder won't wet to stainless, so they separate the pin from the pad when pushed into a molten joint.
 

Online xavier60

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Re: Problem with removing solder...clearing pin.
« Reply #10 on: January 01, 2019, 10:40:27 am »
I use a large sewing needle. It's easy to pull out because it is tapered.
HP 54645A dso, Fluke 87V dmm,  Agilent U8002A psu,  FY6600 function gen,  Brymen BM857S, HAKKO FM-204, New! HAKKO FX-971.
 

Offline GreyWoolfe

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Re: Problem with removing solder...clearing pin.
« Reply #11 on: January 01, 2019, 01:26:11 pm »
I have a dental pick for this purpose.
"Heaven has been described as the place that once you get there all the dogs you ever loved run up to greet you."
 

Offline Brumby

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Re: Problem with removing solder...clearing pin.
« Reply #12 on: January 02, 2019, 12:34:22 am »
Well .... that's what a toothpick is, after all...    ;D
 

Offline RobertHolcombe

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Re: Problem with removing solder...clearing pin.
« Reply #13 on: January 02, 2019, 12:44:10 am »
To clear PTH I often apply additional solder and while the solder is molten give the board a light tap on a rubber pad. The force is usually enough to remove all the solder and any remaining component leads. Obviously only applicable to smaller boards which can be hand held, and not suitable for delicate parts ;D
 
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Offline GreyWoolfe

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Re: Problem with removing solder...clearing pin.
« Reply #14 on: January 02, 2019, 12:27:08 pm »
Well .... that's what a toothpick is, after all...    ;D

It surely is.  :-DD
"Heaven has been described as the place that once you get there all the dogs you ever loved run up to greet you."
 


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