De-soldering Advice - Loosing My Mind - Page 1
Forum section: electronics / repair

author: daryl_uk
author_rank: Newbie
timestamp: January 17, 2018, 11:07:57 pm
content: Hello Everyone,I am having a nightmarewith trying to remove solder from small through holes on an oldish (cica 1990) PCB. I am trying to replace some knackered caps, the pads are tiny.I managed to get some caps out but there was solder left behind - I am using a standard soldering iron, solder wick and flux (maybe I need a temp control one?).I have tried adding fresh solder to the joint; and then the solder wick again but always there's a bit left behindIts getting to the point now where I am starting to damage the boardhttps://www.eagle-eyes.me/photos/electronics/DSC_0005_015_m_s.png

author: keymaster
author_rank: Regular Contributor
timestamp: January 17, 2018, 11:31:04 pm
content: you need a desoldering pump . even a cheap one will do the job.

author: jpanhalt
author_rank: Super Contributor
timestamp: January 17, 2018, 11:32:47 pm
content: Sometimes adding more solder, then use a good wick will clean them up. I use Chemtronics wicks exclusively and suspect there must be other good ones out there, but why change.Second, heat the hole and flick it to remove solder.Third, get a small piece of music wire smaller than the hole. Heat the hole and push the music wire through. That will usually clear the hole. It is quite rare that I reach this step.

author: james_s
author_rank: Super Contributor
timestamp: January 17, 2018, 11:38:24 pm
content: Wick is useless for a board like that with loads of thermal mass. You need a real desoldering tool, Hakko 808 or similar device with temperature control and a vacuum pump. I usually add a bit of fresh solder to get things going. In a pinch you can heat the pads one at a time and wiggle the old cap out but be careful not to rip out the through-hole plating.

author: helius
author_rank: Super Contributor
timestamp: January 17, 2018, 11:42:16 pm
content: You won't get the solder to flow out of the hole without either A) wetting your braid with liquid flux; or B) using a solder sucker. You can use either of these approaches. Vacuum desoldering tools will also work but are very expensive compared to the above—abottle of liquid fluxis $7.50 and a high-end solder sucker can be had foras low as $6.

author: Safar
author_rank: Regular Contributor
timestamp: January 17, 2018, 11:46:40 pm
content: Just try to use toothpicks after melt solder. With flux of course.Syringe needle (stainless steel) can help also

author: Alex Eisenhut
author_rank: Super Contributor
timestamp: January 18, 2018, 12:19:26 am
content: Uh oh, I've been through this before...http://www.ebay.ca/itm/Mini-Micro-Hand-Drill-with-Bits-for-Craft-Modeling-Making-Hole-Jewelry/263281896204?hash=item3d4cd2eb0c:g:bF4AAOSwjyhZ8QY5This works perfectly if you use a minimum of care and common sense. You simply turn the drill bit and let it do the pulling, press as little as possible, and stay true (normal to the PCB).

author: The Soulman
author_rank: Super Contributor
timestamp: January 18, 2018, 12:32:13 am
content: Assuming you're going to place a new part, warm up the pad until the solder liquefies (adding some new solder usually helps) and poke the leg of the the new part thru,typically it solidifies after poking thru about a cm because of the cold leg of the new part.Simply reapply heat and push the part down, when all the way down cut the leg to length and re-solder with some fresh solder.As always when soldering, never heat up to long and never to short and don't apply mechanical force to components and/or pads.

author: Buriedcode
author_rank: Super Contributor
timestamp: January 18, 2018, 12:42:10 am
content: As you've noticed, the more times you apply heat the more the pad will lift. Beyond 3 times is usually the danger zone.If you have no other equipment, then, yes, adding fresh solder, keeping the iron there for a second or two, then with the iron tip slightly in the hole, lift the pcb up, and tap it on a hard surface. It isn't ideal but it often lets the liquid solder fly out leaving a relatively clean hole. One has to ensure the solder is molten through the hole, a temperature controlled iron really does help a lot. (preferably >40W).Option 2 is a desoldering pump. For stubborn holes, I've found it best to have the PCB at a 90 degree angle - with an edge facing you. Place the pump over the hole on one side, then use the iron on the otherside. It can get tricky without a clamp, but it can be done.Desoldering braid is great but extra flux on it almost always helps. In fact, put some on the offending pad/hole. The wick will... well, wick, that up and solder will flow with it.As insurance, if you have time, look at the traces that go to that pad, and get some wire handy, just incase you pull the PTH out.

author: phil from seattle
author_rank: Super Contributor
timestamp: January 18, 2018, 01:02:09 am
content: a cheap solder pump will usually do the trick. You can buy powered vacuums or drills or what ever but I've found a cheap little solder sucker works great. It's best if you can get access to both sides of the PCB. Soldering iron on one side, cocked sucker (no jokes please!) on the other, let it heat for about 2 seconds and then hit the release. Whoosh! Problem solved. This one is from adafruit.https://www.adafruit.com/product/148

author: james_s
author_rank: Super Contributor
timestamp: January 18, 2018, 01:04:39 am
content: I never had any luck at all with those solder suckers but maybe I just never used one right. For years I got by with a rubber bulb desoldering iron but once I got a good vacuum desoldering gun it was like night and day, I could never imagine going back.

author: phil from seattle
author_rank: Super Contributor
timestamp: January 18, 2018, 01:39:43 am
content: Well, yeah. A powered one will work a lot better. But those little spring powered suckers work pretty well and are very cheap. If I was doing a lot of desoldering of through hole components, I'd definitely have a powered one. But I mostly do SMDs. So I use a hot air rework station to get the parts off and braid works great for cleaning the pads.

author: PaulAm
author_rank: Frequent Contributor
timestamp: January 18, 2018, 02:06:03 am
content: 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.

author: james_s
author_rank: Super Contributor
timestamp: January 18, 2018, 02:08:43 am
content: If I'd known how great a vacuum desoldering tool was I'd have bought one years earlier. It turns desoldering a 40 pin DIP from a double sided PCB from a dreaded task I'll try when I'm almost certain the IC is bad to something I can do in a few minutes almost on a whim to test something.

author: tautech
author_rank: Super Contributor
timestamp: January 18, 2018, 10:29:55 am
content: Quote from: phil from seattle on January 18, 2018, 01:02:09 amI can vouch for one of these^^Mines had a beating for at least 20 years, fallen to bits a couple of times and needed to be stripped and cleaned every once in a while too. Still on original O-ring.It's got a little dish in one side of the nozzle now that is where I always have the iron and that dish helps make any gap for the suction to escape somewhat smaller.Even migrating to SMD I've not seen any need to replace it with anything smaller however anything smaller than 0805 disappears up the spout.For the OP, rework, get 2 things, a sucker or desoldering iron and some low temp solder to blend in on stubborn joints and lower the heat needed.But that presumes you have a reasonable iron, something it appears you don't.If you get one, get a hot air station too and when you get really stuck with a heat robbing joint you can add some hot air into the mix too.

author: Bashstreet
author_rank: Frequent Contributor
timestamp: January 18, 2018, 11:08:15 am
content: Quote from: tautech on January 18, 2018, 10:29:55 amWell yes they "kind of work" takes quite bit of trial and error to get it right tho.If what he is doing is just cap replacement he can just heat up the solder to poke the leg in what is easy enough.Really a solder vacuum station is way to go.. I get one when i can afford till that i have to get by suckers and all sorts.. Removing 40 pin chips.. what a joy..If you have good tips how to use a sucker please share i try follow."Hoping one day Santa brings every electronics repairman (and woman) a solder sucker stations at Xmas"

author: Ian.M
author_rank: Super Contributor
timestamp: January 18, 2018, 11:35:53 am
content: 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). The difference is incredible - you can reduce the cleaning interval by anything up to an order of magnitude and still get a better seal than it has with the normal cleaning interval. To test how good the seal is, simply moisten your fingertip and hold it tightly over the tip while triggering the solder sucker - the plunger should move gradually, taking several seconds for its full travel.To make the wiper, cut several disks of waxed paper (saturate copier paper with paraffin wax on a flat hot surface and wipe off excess before it cools) that are just a fraction larger than the barrel bore so they cup slightly and scrub the solder dust off the bore as you re-cock the piston. Use a hole punch to make the center hole for the spike that clears the nozzle and fit them between the spring and the piston. Its best to punch the center hole first through the rough cut disks then trim them to size so that their outer edge is concentric with the center hole.You will find that the disk next to the spring wears the most and when it gets too tatty it can be discarded exposing the next one in the stack, but there should always be at least three left. When you clean the chamber, you should clean the O rings or cup seal on the piston with an old toothbrush if there is any buildup of solder dust, and occasionally apply a drop of light silicone oil (copier fuser oil is ideal) to keep the seal(s) and bore lubricated.You can also improve the nozzle - a short length of fairly thin walled silicone rubber tubing pushed over the tip will let it seal to the board: Clamp the board vertically and heat the hole to clear from the side with the most copper, using a large hoof bit, with a little flux and fresh solder, sucking from the other side with the sucker normal to the board so it gets a good seal and all the suction is applied to the hole.N.B. it wont be anti-static, but nor is the normal white Teflon nozzle. If working with highly ESD sensitive devices, buy a black carbon loaded static dissipative nozzle and *DON'T* add silicone tubing.Another useful tool is a mounted steel needle fractionally thicker than the component lead. It can be inserted into a hole from the side with the least copper while heating the other side to clear the hole. After removing the iron keep rocking the needle fractionally in the hole as the solder cools to maintain enough clearance for easy withdrawal of the needle. If the resulting hole isn't clean enough, it can often be improved with a drop of flux and reheating next to but not covering the hole.If you don't have a heat resistant miniature pin vice handy, you can make a mounted needle starting with a sewing needle. Use a thin wooden dowel for the handle, insert and remove the needle in the end to make a hole, then ligtly sand the eye end of the needle to roughen it, apply a drop of superglue to it and force it into the dowel for 1/3 of the needle length. The needle needs to be bright polished steel, not gold or brass plated, and should be kept lightly oiled or waxed so solder doesn't wet it.If your iron cant supply enough heat to keep the solder molten all the way through the hole, with the biggest hoof bit you can get for it, you need a higher wattage iron. Temperature controlled is preferable - at least 50W, but with practice you can do a good job even with something as crude as a 100W Weller soldering gun - get the joint melted and sucked quickly before the high bit temperature has time to significantly cook the board.When desoldering DIL package ICs in plated through hole boards, after sucking as much solder as possible from the hole, flex the pin slightly with a fine jewellers screwdriver or other blunt ended probe to hold it away from the wall of the hole so it doesn't stick as it cools. You may need to add a drop of flux and alternately reheat the pad and the pin while flexing it to clear any solder whiskers to get the pin free in its hole. If there is much solder on the shoulder of the pin you may have to use flux and braid from the top side after sucking the hole. The amount of care taken freeing each pin direct contributes to the odds of you avoiding signifiicant board damage.

author: GreyWoolfe
author_rank: Unknown
timestamp: January 18, 2018, 12:54:34 pm
content: I have good wick and a desoldering pump. That said, I have had solder that couldn't be removed with either. I use a dental pick that I heat up with the soldering iron and gently push through the hole. Easy, peasy to use braid for cleanup.

author: Rasz
author_rank: Super Contributor
timestamp: January 18, 2018, 01:27:49 pm
content: as Safar and Ian.M already said - stainless hypodermic needle, or just heat via up, lube the hole with flux and fresh solder and shove new components leg in theremechanical solder suckers are junk, but most people learn that only after using good desoldering gun ;-)

author: ArdWar
author_rank: Frequent Contributor
timestamp: January 18, 2018, 01:47:50 pm
content: Just be careful when using those solder suckers, especially on pads that had been subjected to too much heat/heated multiple times where the copper binder maybe got weakened. They'll suck the entire pad and traces.For conditions like this, I'll just use some unused component wires (usually resistors as they're the thinnest one) to poke thru the hole. Usually the solder will stick to the wire.

author: Armadillo
author_rank: Super Contributor
timestamp: January 18, 2018, 01:48:34 pm
content: Wow, all the joy here, when the matter is heating up. LOL....

author: tablatronix
author_rank: Regular Contributor
timestamp: January 18, 2018, 02:17:39 pm
content: Buy a $50 hot air station, much cheaper than a de-soldering station, and you can just blow the shit out.

author: kelchm
author_rank: Regular Contributor
timestamp: January 18, 2018, 02:20:47 pm
content: 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 theEngineer SS-02. This is more expensive than the cheap ones, but it's very well built and worth the extra money in my opinion.

author: Fludo
author_rank: Regular Contributor
timestamp: January 18, 2018, 03:32:54 pm
content: If you heat the hole up and melt the solder, quickly tapping it on your workbench will launch most of the solder out without any tools.

author: sreeb
author_rank: Contributor
timestamp: January 18, 2018, 06:42:23 pm
content: For really challenging cases, I have used compressed air. Heat it up and blow it out.Think about where the solder is going to go....

author: james_s
author_rank: Super Contributor
timestamp: January 18, 2018, 06:54:40 pm
content: Definitely wear eye protection if you try that, it's possible to blow it back at yourself.

author: phil from seattle
author_rank: Super Contributor
timestamp: January 18, 2018, 07:07:15 pm
content: Quote from: kelchm on January 18, 2018, 02:20:47 pmThat 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.

author: Bashstreet
author_rank: Frequent Contributor
timestamp: January 18, 2018, 07:44:43 pm
content: Quote from: phil from seattle on January 18, 2018, 07:07:15 pmUsing 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.

author: perkabrod
author_rank: Contributor
timestamp: January 18, 2018, 07:59:35 pm
content: – 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.

author: tooki
author_rank: Super Contributor
timestamp: January 19, 2018, 02:34:34 am
content: Good solder wick is already coated in flux and thus shouldn’t oxidize quickly.

author: xrunner
author_rank: Super Contributor
timestamp: January 19, 2018, 02:41:28 am
content: 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

author: sreeb
author_rank: Contributor
timestamp: January 19, 2018, 03:07:26 am
content: Quote from: xrunner on January 19, 2018, 02:41:28 amAt $1.25 I bought a set. Can you elaborate on their usage?

author: xrunner
author_rank: Super Contributor
timestamp: January 19, 2018, 03:14:35 am
content: Quote from: sreeb on January 19, 2018, 03:07:26 amThey 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..

author: Alex Eisenhut
author_rank: Super Contributor
timestamp: January 19, 2018, 04:00:45 am
content: Interesting. I'll give these a try.

author: kalel
author_rank: Frequent Contributor
timestamp: January 19, 2018, 07:18:53 am
content: Quote from: sreeb on January 19, 2018, 03:07:26 amThose 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.

author: JacquesBBB
author_rank: Frequent Contributor
timestamp: January 19, 2018, 09:05:47 am
content: 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:mNjfoPaU0lPf99xAh3V3FeQYou 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.

author: David Hess
author_rank: Super Contributor
timestamp: January 19, 2018, 03:43:32 pm
content: 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

author: daryl_uk
author_rank: Newbie
timestamp: January 23, 2018, 09:35:31 am
content: Thank you for all the great advice.I now have a temperature controlled solder stationBetter quality solderA selection of different width of wicksWith 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.

author: alsetalokin4017
author_rank: Super Contributor
timestamp: January 23, 2018, 10:22:29 am
content: 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.QuoteBut 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.

author: David Hess
author_rank: Super Contributor
timestamp: January 23, 2018, 02:55:35 pm
content: Quote from: alsetalokin4017 on January 23, 2018, 10:22:29 amIt 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.QuoteChip-Quik is pretty expensive but it is what I would use for paid repairs.QuoteEven heating the pad/hole is sometimes not enough to walk the leads out easily.

author: Shock
author_rank: Super Contributor
timestamp: January 23, 2018, 03:20:23 pm
content: Quote from: Ian.M on January 18, 2018, 11:35:53 amCan you take a photo of this?

author: cdev
author_rank: Super Contributor
timestamp: January 23, 2018, 04:08:12 pm
content: 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.Quote from: David Hess on January 23, 2018, 02:55:35 pm

author: David Hess
author_rank: Super Contributor
timestamp: January 23, 2018, 04:26:06 pm
content: Quote from: Shock on January 23, 2018, 03:20:23 pmI 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.

author: Ian.M
author_rank: Super Contributor
timestamp: January 23, 2018, 04:46:52 pm
content: 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 useChipQuikor 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.

author: Bashstreet
author_rank: Frequent Contributor
timestamp: January 23, 2018, 09:03:11 pm
content: Quote from: alsetalokin4017 on January 23, 2018, 10:22:29 amWell 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

author: pinkman
author_rank: Regular Contributor
timestamp: January 24, 2018, 05:11:45 am
content: 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.

author: texaspyro
author_rank: Super Contributor
timestamp: January 25, 2018, 01:05:19 am
content: 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.

author: sokoloff
author_rank: Super Contributor
timestamp: January 25, 2018, 01:16:08 am
content: Quote from: PaulAm on January 18, 2018, 02:06:03 amI 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.

author: Alex Eisenhut
author_rank: Super Contributor
timestamp: January 25, 2018, 01:27:09 am
content: Quote from: Bashstreet on January 23, 2018, 09:03:11 pmI *do* hope you're joking.

author: macboy
author_rank: Super Contributor
timestamp: January 25, 2018, 05:12:33 pm
content: 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, youmusthave 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.

author: B1nary
author_rank: Contributor
timestamp: January 26, 2018, 04:49:37 pm
content: I was having the exact same problem re-capping an amateur radio and tried what is being suggested herein. I have a desolder gun and it wasn't helping. In fact some caps came out easily and others were a rear bear to get out. My solution was to use the de-solder gun to release the first pin of a cap, if the second pin would not come out I then used a temp controlled solder station set to 325 degrees -- far too hot normally, but I held it on the cap pin until the cap could be pulled out easily. Nothing I tried after that would remove the solder filled through hole - so I picked up a small pin vise (looks like a baby manual hand drill) and I bought small very small number drill bits. The drill bit I am using now is .61mm but you can buy them in thousand inch sizes as well. This solution works for me. A word of caution - don't be hamfisted with the pin vise or you will break the bit.

author: Samogon
author_rank: Frequent Contributor
timestamp: January 26, 2018, 05:15:37 pm
content: This issue with caps usually due to huge thermal mass where negative pin is soldered. Usual thing for power rail filter caps. Sucking out solder from positive side, then while heating negative, wiggling out cap. Then you can use toothpick to push out solder left in the hole.

author: rsjsouza
author_rank: Super Contributor
timestamp: January 26, 2018, 05:17:39 pm
content: Quote from: xrunner on January 19, 2018, 03:14:35 amTHANK YOU!!! My dad had a Philips branded desoldering tool like this and it was great to use in most cases. This tool was lost and I could never find something similar.

author: kalel
author_rank: Frequent Contributor
timestamp: January 26, 2018, 05:29:26 pm
content: For the price, they seem useful but also some care should be taken to not damage anything (I don't know how likely that is to happen).

author: rsjsouza
author_rank: Super Contributor
timestamp: January 26, 2018, 05:41:14 pm
content: It can happen, kalel.In the early days of using this tool, I recall obliterating pads while vigorously rotating it, as I thought there was solder in the hole that was blocking it from going over the other side. In fact, the size I was using was wrong and I was actually drilling a larger hole instead...

author: dl1640
author_rank: Regular Contributor
timestamp: February 01, 2018, 10:33:21 am
content: Normally I use Hakko 701 station (desoldering gun ) for best result but tap the board on a workbench is also considerable if filled with excessive solder.

author: cdev
author_rank: Super Contributor
timestamp: February 01, 2018, 05:25:43 pm
content: Did you watch Dave's video on "Chip Quik"? (low temperature solder for desoldering SMDs)

author: ErwinsCat
author_rank: Regular Contributor
timestamp: February 02, 2018, 06:37:43 am
content: when I have a similar freak non-cooperating pad to desolder, usually get a peace of nic-chrome (i get them from a hair dryer or a similar heater) or a small piece of aluminum enameled/magnet wire. heat up the pad and push the wire through. If you ever tried to solder those wires you would learn very soon they (almost) impossible to solder with the normal flux and solder wire. so you push one off those into the hole and you would be sure you could pull them out without getting stuck in the holes.

author: daedalux
author_rank: Contributor
timestamp: February 04, 2018, 09:03:56 pm
content: A injection needle of a enough size will get the wire nicely when desoldering and break the joint so the component will be free by just pulling the needle after cooling. It's a miracle for removing a dip package on the cheap for example. They are stainless steel and solder alloy won't stick to them. There are comercial devices similar with a grip and without a sharp point called desoldering needles.

author: mixiom
author_rank: Contributor
timestamp: February 19, 2018, 04:45:28 pm
content: Quote from: xrunner on January 19, 2018, 02:41:28 amI have bad experience with those. Maybe they do work if the legs of the component are straight up, but many times the legs have been bend and you cannot slide the tool over the leg. Trying to bend the legs with the tool broke it apart; it is very brittle (I speak for the cheap ebay one), perhaps not real steel, I dont know. Also, many of the time the component legs are not only bend, but they are so wide that there is not enought room in the hole for the tool to slide over it; so you reach for a smaller tool diamater but that does not fit on the leg and you push and twiggle without success - it was frustrating to me. Perhaps if the circumstances (big hole, straight legs, etc) are right, this tool could work, but it is not a universal solution.

author: BravoV
author_rank: Super Contributor
timestamp: February 19, 2018, 05:46:58 pm
content: Quote from: daedalux on February 04, 2018, 09:03:56 pm+1Used to use just ordinary injection needles, just buy various different sizes, as they're relatively cheap and easy to get locally, at least here, and quite effective too. Only stopped using them once I got my Hakko de-soldering gun.Its true stainless steel and real hard & strong, and solder wont stick to it at all.Random google images.

author: daedalux
author_rank: Contributor
timestamp: February 21, 2018, 02:56:02 pm
content: I've succesfuly freed pcb holes:-Adding more tin and blowing quick.-Inserting a paperclip or needle into the fused joint.-Not even freeing it, just inserting the new component lead in the joint and once in patiently melting both in. Not very recomended.-Drilling it with a hand drill and an small bit, it's the only cold method and very good on a valuable board, with a well choosen bit, it will not destroy the via in the hole.-Usually the method of choice is desoldering pump (must suck good, don't use the smallest ones) that you must learn how to use as its tricky to suck good without the joint solidifying. In smd and if refination is needed use solder wick. If the component is still in and has more than two nearby leads you must have pump, wick or both.-Solder wick of good quality can solve anything, but it is slow and you expend it fast, and the good one is not so cheap, if it's bad you'll have to add flux to it.

author: Ray Gianelli
author_rank: Contributor
timestamp: February 26, 2018, 10:43:36 am
content: Quote from: helius on January 17, 2018, 11:42:16 pmAgree. The Hakko desoldering tools are not cheap, but still rate as good bang for your buck with me.In this application tip size is critical. You need a tip small enough to match the hole size. Then it's quick and effective.

author: mr.fabe
author_rank: Regular Contributor
timestamp: February 28, 2018, 02:58:41 am
content: Quote from: Ray Gianelli on February 26, 2018, 10:43:36 amI was in the market for the Hakko FR-300 and I stumbled upon this Velleman VTDESOL3U for about $9. This cheapo desoldering iron works great. Although it has a huge hole in the tip, with proper technique, it works extremely well. Set the plunger, put iron over pad with the wire touching the inner edge of the iron hole. When the solder start to flow, move the tip in a circular motion around the joint and press the button for suction. Voila! Clean pads with little need for any wicking. Worked very well on boards with pads on both sides. Pleasantly surprised with this thing.Sent from my XT1575 using Tapatalk

author: KL27x
author_rank: Super Contributor
timestamp: February 28, 2018, 04:29:55 am
content: QuoteI avoid adding more solder/flux. Flux just clogs the sucker.What I do is get a 3mm bevel tip on the pad then put the sucker OVER the pin and iron tip while pressing the button. (The button is the only thing moving!) Eventually you will melt a notch in the tip which fits over the iron just right, but you can speed things up and cut or file a notch. If you try to extract the tip while trying to push the tip down against the pcb and pressing the button at just the right moment, you might be doing it wrong.A good sucker helps. I can recommend the Edsyn Sodapult and Edsyn Sodapult 3. The peak suction of a good sucker is higher than any desoldering station (if you're using it, correctly). A desoldering gun might be able to provide more heat, though, for those multilayer boards. But that depends on what soldering station you use, of course.

author: KrudyZ
author_rank: Frequent Contributor
timestamp: February 28, 2018, 06:29:27 am
content: Quote from: cdev on February 01, 2018, 05:25:43 pmI second this suggestion. It really works wonders on things like shielding cans or big MOSFETs.I use a dedicated tip to for my iron to desolder with Chip Quick solder and then completely remove the remaining solder with either a sucker or solder wick.It does not wet well and requires some more thorough clean-up, but it's worth the effort.

author: dictatim
author_rank: Newbie
timestamp: March 05, 2018, 11:27:21 am
content: I have been repairing electronic equipment for nigh on sixty years and have picked up a few tips and tricks on the way.One, relevant to this discussion, was how to deal with removing DIL ICs. Almost invariably this is done with the intention of fitting a replacement so it is not necessary to remove the old one intact. Simply using fine, sharp sidecutters (or even a sharp craft knife) cut off the pins where they emerge from the plastic body, remove the body, heat the solder and remove each pin in turn using fine tweezers. The vias can then easily be cleared using a solder sucker.Also, when re-capping PC motherboards, power supplies etc., I have had considerable success removing old components by using sharp, fine sidecutters to slice off the pins - together with the mound of solder - very close to the surface of the solder side of the board. Most complex boards are wave soldered and the solder doesn't actually suck up into the via so it's possible to lever the component away from the board without the need to apply any heat.On most solder jobs it's essential to 'alloy' the existing lead free solder with 60-40 lead/tin solder to lower the melt temperature. It seems to retain its heat and stay fluid a little longer too.

author: ogden
author_rank: Super Contributor
timestamp: March 05, 2018, 12:07:28 pm
content: Preheating the board with heatgun or special IR heater is key to success in through-hole (capacitor) rework on multilayer PCB. I just set around 200..250oC air temp, heat PCB bottom area around capacitor, use powerful enough soldering iron with additional lead solder for better heat transfer and no struggle at all.

author: xxx2fan
author_rank: Contributor
timestamp: September 10, 2018, 09:23:32 pm
content: Google is your friend, Google desoldering vac from old refrigeration compressor, Should be able to find one easy they have to come out of Refrigs etc to scrap them. A filter to keep the solder out of the unit and oh well Google it.Just a idea, have had one for years and finally got a premade one LOL not much difference except the homemade one has more suction.

author: cdev
author_rank: Super Contributor
timestamp: September 11, 2018, 03:32:21 pm
content: I am using the large knife tip on my old soldering iron now for desoldering. Its really good for that.Quote from: KL27x on February 28, 2018, 04:29:55 amI have a small plastic bellows pump as well as a small HEPA vacuum with foot switch that I have successfully used as one hand solder suckers. You can use a large glass bottle as a gravity trap so that the solder doesn't go into the pump/vacuum or whatever.The Chip Quik is great stuff, a little bit of it goes a very long way. Combined with preheating especially.

author: jmelson
author_rank: Super Contributor
timestamp: September 11, 2018, 08:24:04 pm
content: OK, here's my method. First, get a solder sucker, there are a couple types. The sucker-only types work, but you have to be very fast to heat the joint, then replace soldering iron with sucker and trip the sucker before the joint cools. Or, there are types that have the heating element with a hollow solder tip/nozzle, that gets rid of the quick switch problem.So, use the solder sucker to remove the old solder, it might be lead-free, and need a LOT of heat to melt. Then, replace the old solder with lead-based (or low-temp solder, if you have it). Replacing the high-temp lead-free solder with even tin/lead solder makes a HUGE difference.Now, remove the component. If a big radial capacitor, you may have to alternately heat one lead and then the other, and rock it off the board.Once the component is removed, then you can clear the hole. If using the sucker-only device, apply the soldering iron to whichever side of the board has more copper on the pad, let it heat for 10 seconds or so, then apply the sucker to the other side and trip the sucker while still holding the soldering iron to the other side.If using a combined heater/sucker, then you can put a soldering iron on the other side, thus heating from BOTH sides of the board. This works amazingly well on heavy multilayer boards like computer motherboards. Make sure the through hole in the board is FULL of solder before doing this, the solder will help the entire hole be molten, so it gets completely sucked out.I've not had ANY luck with desoldering braid on multilayer boards through holes.Jon

author: Southerner
author_rank: Regular Contributor
timestamp: January 15, 2019, 06:40:55 am
content: Quote from: PaulAm on January 18, 2018, 02:06:03 am

author: Southerner
author_rank: Regular Contributor
timestamp: January 15, 2019, 06:43:52 am
content: Quote from: jmelson on September 11, 2018, 08:24:04 pmA third type is a desoldering tip that has a squeeze bulb coming off of it. I tried to find one to fit my Weller WTCPT but was unable to find one even though they make them. I ended up buying a cheap 110vac soldering pencil that had that type of desolder bulb. They definitely work better with a temperature controlled iron though.

author: Terry01
author_rank: Frequent Contributor
timestamp: January 15, 2019, 08:38:18 am
content: This type of solder pump is the best mechanical pump I have had by a country mile! The electric one is good of you are doing a lot of de-soldering but for just 1 or 2 this is awesome! They are quite big though but well worth it for how easy it makes jobs like the one you are up against!

author: David Hess
author_rank: Super Contributor
timestamp: January 16, 2019, 02:50:50 am
content: Quote from: Southerner on January 15, 2019, 06:43:52 amA Weller DS227 vacuum desoldering head will also fit on a WTCPT iron.