De-soldering Advice - Loosing My Mind

[james_s]

Definitely wear eye protection if you try that, it's possible to blow it back at yourself.

[phil from seattle]

A solder sucker was one of the best electronics related purchases I've ever made. I don't think I've damaged a single board since getting it.

I'm using the Engineer SS-02. This is more expensive than the cheap ones, but it's very well built and worth the extra money in my opinion.

That looks like a good one - Being able to easily cock it with one hand is a definite plus. Allows you to work down a row of pins relatively quickly. I can cock mine with one hand but it's a fumble.

[Bashstreet]

A solder sucker was one of the best electronics related purchases I've ever made. I don't think I've damaged a single board since getting it.

I'm using the Engineer SS-02. This is more expensive than the cheap ones, but it's very well built and worth the extra money in my opinion.

That looks like a good one - Being able to easily cock it with one hand is a definite plus. Allows you to work down a row of pins relatively quickly. I can cock mine with one hand but it's a fumble.

Using those suckers on large IC'a (old school) is still huge pain not even really worth it.. for them you really need desoldering gun.

That said i have had to use them and it is really pain in ass . You easily end using too much heat adding new solder and flux.... trying to suck it clean again.. failing redoing.. sometimes it works first go some are really stubborn pins... really pain in ass.

[perkabrod]

– Apply more solder prior to sucking the solder with a solder sucker.

– Use brand name solder wick, I use chemtronics which is very good. GET A FLUX PEN AND APPLY FLUX on the joint and/or the wick.
I used to think solder wick was a piece of crap til' I got a job at an electronics company where I could ask for advices on soldering process etc. And flux is key. Also, don't buy too much solder wick, it oxidizes and won't work half as good then.

[tooki]

Good solder wick is already coated in flux and thus shouldn’t oxidize quickly.

[xrunner]

Get a set of desoldering needles, they can work wonders -

https://www.ebay.com/itm/8PCS-Stainless-steel-Hollow-needles-desoldering-tool-electronic-components/222763022945?hash=item33ddb5fa61:g:Q0YAAOSwVtZaOcgo

[sreeb]

Get a set of desoldering needles, they can work wonders -

https://www.ebay.com/itm/8PCS-Stainless-steel-Hollow-needles-desoldering-tool-electronic-components/222763022945?hash=item33ddb5fa61:g:Q0YAAOSwVtZaOcgo

At $1.25 I bought a set.  Can you elaborate on their usage?

[xrunner]

At $1.25 I bought a set.  Can you elaborate on their usage?

They are stainless steel so do not adhere to solder. They are also hollow like a needle. So you can heat up the joint with the wire still in the hole. Just pick the correct size needle. Get the hole hot so as to melt all the solder, and poke the needle through the hole from the other side. The hollow of the needle will allow the wire to enter it. Then when it cools, the wire is now not attached to the plating of the board. You can then remove the component. If the component wire has already been pulled out, simply do the same thing anyway, it will clean out the hole just the same.. 

[Alex Eisenhut]

Interesting. I'll give these a try.

[kalel]

Get a set of desoldering needles, they can work wonders -

https://www.ebay.com/itm/8PCS-Stainless-steel-Hollow-needles-desoldering-tool-electronic-components/222763022945?hash=item33ddb5fa61:g:Q0YAAOSwVtZaOcgo

At $1.25 I bought a set.  Can you elaborate on their usage?

Those are interesting, and while I haven't tried them (yet) they should be helpful. There are also cheap desoldering pump + iron combinations. Manual ones, that look similar to the hand desoldering pumps described above, but have an unregulated soldering iron built in as well. They can cost pretty much the same as some of the higher quality manual desoldering pumps that don't have the iron built in, and could be easier to use (you can heat up the joint and then use the vacuum directly). I'm sure the fully automatic ones will be better, but even the cheap manual ones seem to work very well and can be cost effective.

[JacquesBBB]

For difficult cases,  I use some low melting point solder paste like this one, with 138°C melting point.
https://www.ebay.com/itm/200g-XG-250-XG-80-XG-Z240-Solder-Paste-Low-Temperature-Melting-Point-138-C/322978135969?hash=item4b32ff3fa1:m:mNjfoPaU0lPf99xAh3V3FeQ

You add it to the joint. It will gradually mix with the existing solder and will lower the  melting point of the whole, making it more easy to desolder.

[David Hess]

Like Alex Eisenhut, I have had good results using a set of micro sized drill bits and a pin vice.

https://www.micromark.com/mini-hand-tools/drill-bits-pin-vises

[daryl_uk]

Thank you for all the great advice.   

• I now have a temperature controlled solder station
• Better quality solder
• A selection of different width of wicks

With the new tools I managed to remove successfully the bad caps that were still in situ.
The empty pads (removed with my old crappy tools) are a different story; I have still not been able to remove the remaining solder no matter how much I try so I have now ordered tiny drill bits to clear the holes.  Even heating the replacement cap legs and trying to push them through cannot heat up the board enough to make the solder in the pad hole molten.

[alsetalokin4017]

Drill bits?? Aren't you at all concerned about removing the thru-plating of holes in a multi-layer PCB? Tektronix recommends using a wooden toothpick to clear the holes, to avoid damage. Of course that requires being able to melt the solder!

If you can't get the solder to melt, you could try using some Chip-Quik alloy on it to lower the melting point.

Even heating the replacement cap legs and trying to push them through cannot heat up the board enough to make the solder in the pad hole molten.

But that's not how to do it. Heat the solder in the pad/hole with the soldering iron, not the component leads. Once the leads make it through the hole, then resolder for a complete joint.

[David Hess]

Drill bits?? Aren't you at all concerned about removing the thru-plating of holes in a multi-layer PCB? Tektronix recommends using a wooden toothpick to clear the holes, to avoid damage. Of course that requires being able to melt the solder!

It has never been a problem while getting enough heat into the pad to remove the solder through other means has sometimes resulted in disconnected the pad from the plated through hole and lifting it.  I have had more success drilling than heating but it takes longer.

If you can't get the solder to melt, you could try using some Chip-Quik alloy on it to lower the melting point.

Chip-Quik is pretty expensive but it is what I would use for paid repairs.

Even heating the replacement cap legs and trying to push them through cannot heat up the board enough to make the solder in the pad hole molten.

But that's not how to do it. Heat the solder in the pad/hole with the soldering iron, not the component leads. Once the leads make it through the hole, then resolder for a complete joint.

Even heating the pad/hole is sometimes not enough to walk the leads out easily.

[Shock]

Cheap solder suckers with the spring in the chamber can be much improved by adding a wiper to keep as much solder dust as possible away from the piston seal(s).

Can you take a photo of this?

[cdev]

I find a second supplemental source of heat makes all the difference.
I use a hot plate, not set to the solder MP, set quite a bit lower but its presence makes it possible to do the desoldering when otherwise its an exercise in frustration.

I'm also going to get some Chip-Quik to have around, a little bit goes a long way, Ive heard.

Drill bits?? Aren't you at all concerned about removing the thru-plating of holes in a multi-layer PCB? Tektronix recommends using a wooden toothpick to clear the holes, to avoid damage. Of course that requires being able to melt the solder!

It has never been a problem while getting enough heat into the pad to remove the solder through other means has sometimes resulted in disconnected the pad from the plated through hole and lifting it.  I have had more success drilling than heating but it takes longer.

If you can't get the solder to melt, you could try using some Chip-Quik alloy on it to lower the melting point.

Chip-Quik is pretty expensive but it is what I would use for paid repairs.

Even heating the replacement cap legs and trying to push them through cannot heat up the board enough to make the solder in the pad hole molten.

But that's not how to do it. Heat the solder in the pad/hole with the soldering iron, not the component leads. Once the leads make it through the hole, then resolder for a complete joint.

Even heating the pad/hole is sometimes not enough to walk the leads out easily.

[David Hess]

Cheap solder suckers with the spring in the chamber can be much improved by adding a wiper to keep as much solder dust as possible away from the piston seal(s).

Can you take a photo of this?

I have a good one that uses a replaceable O-ring but I still rarely use it.  The problem is that the inertia of the piston moving away from the joint forces the tip against the joint smashing the board material under the pad which is already weakened by the high temperature.

[Ian.M]

Unfortunately if you've severely 'over-cooked' a joint, the solder can dissolve significant concentrations of additional copper from the pad and/or lead.  This increases the melting point and shifts it away from a eutectic composition.  Wicking such a joint without fully melting it makes the situation worse as it removes  the near eutectic composition liquid leaving the solid crystals with higher copper concentration further increasing the melting point.    Combined with poor thermal transfer due to a dirty joint surface, inadequate iron, or poorly tinned bit, and with large copper planes on inner layers without thermal reliefs, the result can be nearly impossible to rework successfully.   

Generally if a joint isn't melting freely, you need to stop and figure it out rather than carrying on and cooking it.  Clean and tin your bit, apply fresh solder + flux to get better thermal transfer, and it may come good, but if it doesn't you are either going to need to preheat the board to 100 deg C, or use ChipQuik or other similar low melting point alloy to dilute the solder in the joint and lower its melting point sufficiently.

N.B. there are different ChipQuik alloys for SnPb solders and RoHS (lead free) primarily Sn based solders - get the right one for the work you are doing!

@Shock: Photo attached with one paper disk removed to show how its punched.  There are currently seven disks in the wiper stack.  Sorry about the poor photo quality.

@David Hess:  Yes, tip movement can be a problem with delicate pads.   Silicone tubing on the tip helps as it cushions the harder PTFE tip, but if its extremely delicate, a manual sucker isn't the best choice.  You can try a squeezy bulb sucker but I've never been impressed by the level of suction they deliver.

[Bashstreet]

Drill bits?? Aren't you at all concerned about removing the thru-plating of holes in a multi-layer PCB? Tektronix recommends using a wooden toothpick to clear the holes, to avoid damage. Of course that requires being able to melt the solder!

If you can't get the solder to melt, you could try using some Chip-Quik alloy on it to lower the melting point.

Even heating the replacement cap legs and trying to push them through cannot heat up the board enough to make the solder in the pad hole molten.

But that's not how to do it. Heat the solder in the pad/hole with the soldering iron, not the component leads. Once the leads make it through the hole, then resolder for a complete joint.

Well yes i cannot imagine drilling into board through hole being particularly good idea.

It is best use other methods and avoid heavy handed approaches.
I save the hammer treatment to the last   

[pinkman]

I deal with this regularly.

My method, regardless of how much ground plane there is on the (-) side:

1) Remove old cap.  If this is a lead-free board, my first step is usually to add something with a lower melting point (60/40 or chipquick) to the existing joints to assist.  Usually removing the cap is the easiest part (and I assume you found this)

2) Add 60/40 or chipquick or some other low melting point stuff, the pads won't hold much so you can usally get it in there and then wipe the excess away with your iron and it balls up and falls away.

3) Use wick, laid across one side of the board, get wick lengthwise with iron tip (I use a decent size tapered tip) and start in middle of tip, if it doesn't melt immediately then be ready to add a tiny bit of solder to the tip, between tip and braid to get the heat transfer going.  Now gently draw the wick across and away from the pad. 

4) Repeat this for each hole, both sides of the board, usually does the trick.  If not then you can be risky and VERY GENTLY use a drill bit of the right size, or lay some more wick and put the iron on it in such a way that you get quick heat transfer without too much pressure; Adding a little bit of solder can help this process.

I love solder wick and use it almost exclusively unless I'm working on tons of thru hole parts on boards that aren't very delicate or have high glassing temp.  I use a weller WD1 iron and will set it to 800F for a pad with a big GND plane (but not glassing the board is critical in this case!).  I realize that some people prefer other methods but I don't like to clutter my bench with a tool unless I use it a lot.  Everything else goes on the shelf.

[texaspyro]

Solder sucker fun and games:   If you have one of the old pre-safety-weenie solder suckers (blue barrel, spring driven,  large flat yellow cap on the end of the rod, exposed plunger not surrounded by a safety shroud),  try placing a coin on the solder sucker cap and firing the plunger to toss the coin.  The coin almost always lands the same way it was placed.   I won a lot of bets using that trick.

[sokoloff]

Some guy on ebay is selling Edsyn DS017 solder suckers, 2 for $12 shipped.  They're used, but the two I got were in unused condition and just needed regreasing.  Search for Solda Pullt and it will show up.

I have a Metcal desoldering gun, but once in a while the solder sucker is useful.   A good vacuum tool will make that job trivial instead of a trial.

I jumped on this deal and got mine yesterday; just as Paul described, they look unused. (Be aware; they are MUCH larger than what I was expecting.) Good deal, I thought.

[Alex Eisenhut]

Drill bits?? Aren't you at all concerned about removing the thru-plating of holes in a multi-layer PCB? Tektronix recommends using a wooden toothpick to clear the holes, to avoid damage. Of course that requires being able to melt the solder!

If you can't get the solder to melt, you could try using some Chip-Quik alloy on it to lower the melting point.

Even heating the replacement cap legs and trying to push them through cannot heat up the board enough to make the solder in the pad hole molten.

But that's not how to do it. Heat the solder in the pad/hole with the soldering iron, not the component leads. Once the leads make it through the hole, then resolder for a complete joint.

Well yes i cannot imagine drilling into board through hole being particularly good idea.

It is best use other methods and avoid heavy handed approaches.
I save the hammer treatment to the last   

I *do* hope you're joking.

[macboy]

I've replaced through-hole components on multilayer boards (PC motherboards and such), and it can be a pain. If I have a really stubborn bit of solder residue in a hole I resort to this method:
1. heat with liberal amounts of fresh (leaded) solder. You are trying to alloy the old, probably Pb-free solder with the new stuff, while also depending on the flux core of the new solder to help.
2. Remove excess either with wick or suction.
3. If the hole hasn't opened, then: heat and gently press through with a wooden toothpick (perhaps whittled to size) to remove as much as possible.
4. If too much residue remains to allow the new component lead to be inserted, then: Use a pin vise and HSS drill bit (see below) to drill out the remaining solder from the sidewalls of the plated hole. Only go just big enough to allow the component lead through. Solder is much softer than copper, so the drill will only remove solder, not copper... unless you choose too big of a drill. This is only done after the toothpick method above, so that you are only removing solder from the sidewalls of the hole, not drilling through a solid core.

To do step 4, you must have a drill index, with many tightly spaced sizes of drills. These are easy to find and very inexpensive from the usual far-east places. I often use an x-acto knife handle as a pin vise.