Removing solder from stubborn joints - Page 1
Forum section: electronics / repair

author: pharaoh3
author_rank: Contributor
timestamp: October 28, 2021, 12:29:59 am
content: I have a PS4 controller that I want to replace the joystick on, so I disassembled the controller, added flux, added additional solder to all the joints, and removed the faulty joystick with a heat gun. Everything went well, but I ran into a few problems during the next step which was removing all the solder from the joints with a soldering iron, solder sucker, and a wick.The problem is that I have a few joints with a incredibly thin amount of solder that is quite difficult to remove since I can't get my iron and sucker on it at the same time. What is the best way to remove the solder ?I have tried adding additional solder, adding more flux, using a wick, and heating up the board with a heatgun then switching to the iron. I have even tried attaching a resistor to the joint, adding solder, and then attempting to remove the solder again.What do I do?Note: This is for fun/practice, and not for a professional repair, so I am willing to experiment.

author: ataradov
author_rank: Super Contributor
timestamp: October 28, 2021, 12:52:06 am
content: Sharpen a toothpick and poke a hole in the molten solder. Then remove the extra solder that comes out on the other side.

author: pharaoh3
author_rank: Contributor
timestamp: October 28, 2021, 01:01:30 am
content: Quote from: ataradov on October 28, 2021, 12:52:06 amI don't think I could fit my soldering iron and a toothpick on the joint at the same time.Plus, I don't have a toothpick handy...

author: ataradov
author_rank: Super Contributor
timestamp: October 28, 2021, 01:15:53 am
content: Why? There is lots of space on the board. Just hover the toothpick over the hole and once the solder is molten, push it though the hole. This is a standard method for dealing with stuck holes, it always works.Wood can take quite a bit of heat, so heating the annular ring will let you push the toothpick though the hole further.Get anything wooden. There must be something around, like a match.Otherwise you will just destroy the board. There are not too many methods of dealing with this.Also, it does not look like you have enough flux judging by the picture.

author: pharaoh3
author_rank: Contributor
timestamp: October 28, 2021, 02:06:07 am
content: You sound confident that this is the technique to use. I turned in for the day, so I will have to report back tomorrow

author: Microcheap
author_rank: Frequent Contributor
timestamp: October 28, 2021, 02:55:11 am
content: For these situations I have a set of hollow needles like this one:https://www.aliexpress.com/item/33004594843.htmlI use a soldering iron with a chisel tip to better spread the heat, apply some fresh solder and then I poke the hole with the needle of the right diameter, the result is a clean via and no damage to the board.

author: ataradov
author_rank: Super Contributor
timestamp: October 28, 2021, 03:04:07 am
content: I tried those needles, but they are way too big. Plus they are metal and cool down the solder faster. And I always find myself going back to the plain old toothpick.

author: nigelwright7557
author_rank: Frequent Contributor
timestamp: October 28, 2021, 03:28:33 am
content: I use a solder sucker with a silicon tube around the end for a better seal.Sounds counter intuitive but fill hole with fresh solder.Heat up fresh solder and quickly put solder sucker over hole and press the button.Sometimes you have to suck from both sides if other side has a lot of copper attached.Sometimes copper desolder braid helps.

author: mdubinko
author_rank: Contributor
timestamp: October 28, 2021, 03:51:03 am
content: Solder wick should be able to do this, after adding a bunch more flux. Use the pointiest iron tip you have, and heat through the copper wick into the hole and all the solder within should, well, wick right up. It looks like there might be enough solder to saturate a segment of the braid, in which case you might have to move it while maintaining heat. And yeah, if the last bit of solder left is deep down, it can be hard to get it all in one 'slurp'.Mind if I ask what brand of solder wick you're using? I've picked up some wick from Aliexpress that was worse than unusable, but genuine stuff from a reputable source will be orders of magnitude better.Worst case, I would use some low-melt solder to give yourself more working time (and then use wick to clean up all the low-melt solder)-m

author: mzzj
author_rank: Super Contributor
timestamp: October 28, 2021, 04:01:37 am
content: Proper desoldering gun makes night and day difference in this kind of cases. Well worth of the 100-200usd investment if you have more than one-time use for it.Other than that:Preheat the board with hot air gunFill the via with fresh solderUse fluxUse 2 soldering irons simultaneously on both sides of the board (or soldering iron and desoldering gun)And like already mentioned the desoldering braid brand makes big difference!

author: Martian Tech
author_rank: Regular Contributor
timestamp: October 28, 2021, 04:02:35 am
content: Quote from: pharaoh3 on October 28, 2021, 12:29:59 amYou simply use the sucker on the other side of the board from the iron. Stand the board up vertically somehow, put the sucker in place and hold it there while applying heat from the other side of the board with the iron.

author: Microcheap
author_rank: Frequent Contributor
timestamp: October 28, 2021, 04:51:12 am
content: Quote from: ataradov on October 28, 2021, 03:04:07 amI've never tried the toothpick but the hollow needle works nicely for me.I normally just use a solder sucker with a silicon tube on its tip and it does the job for most of the vias but for areas of the PCB with a big cooper plane where the solder will solidify before I can sucker it, I find easier and faster to use those needles.Try to use a bigger chisel tip (I like the T12-D32) with fresh solder and then keep the iron touching the pad while leaving the via accessible for you to insert the needle in it. It works even better if you can heat the pad from the other side of the PCB.I also have a de-soldering station but I rarely use it. The solder wick didn't work for me but that is because I can get only those junk from Aliexpress, good quality stuff should work fine.

author: Haenk
author_rank: Super Contributor
timestamp: October 28, 2021, 07:19:15 am
content: heat with tip from one side, poke from the other sideFor tiny holes, I use a sewing needle, however these are one or two time use only, eventually solder might stick to it.

author: Psi
author_rank: Super Contributor
timestamp: October 28, 2021, 07:37:43 am
content: You can add more solder to make the hole full, then hold the heat on it with a large flat tip, giving it some time to soak. Then, move the iron out of the way fast and instantly blow the solder out by blowing at it really hard at point blank range.But your face has to be very close to it and also gets very close to the iron. So it's definitely a learned skill with a high risk of burning your face if you do it wrong.Another hacky method is to hold the heat on with the iron from one PCB side and then put the nozzle of the vacuum cleaner on the other PCB side. Open the air relief intake value thing a bit, so the suction is not crazybut really, I recommend good quality solder wick and some flux

author: DavidAlfa
author_rank: Super Contributor
timestamp: October 28, 2021, 08:51:51 am
content: I've changed few of these. Rohs solder + multilayer ground planes don't make it too easy.99% of the time it's caused by the iron, lacking power or using a tip head that can't transfer enough heat.So when you thing the solder is melted, it's only the surface layer.The copper braid will take heat from the solder joint, so when there're ground planes involved, it's not the best option!First, use a wide, thick tip, put it on the bottom side, but watching from the top.Add some solder on the top, keep heating until it melts. Now you know it's fully melted all the way through.Take a cheap piston pump, and give it a shot! Clean hole with no effort!Don't be unpatient when heating it up. You want the solder fully melted.If you only take part of it, like in your picture, it'll be very hard to clean.Not only that, It'll require a lot of heat, causing a lot of stress on the pcb and risking to damage it.When that happens, you need to refill it with fresh solder and try again!

author: HB9EVI
author_rank: Frequent Contributor
timestamp: October 28, 2021, 12:40:30 pm
content: for such cases I refresh the pad with new solder and remove it, normally that helps to get the residues from the old solder off with it; if not, some flux from the syringe should help.if all doesn't help, heat up the pad and blow pressurized air through the hole (the use of non-inflammable pressurized air is highly recommended)

author: rfclown
author_rank: Frequent Contributor
timestamp: October 28, 2021, 01:46:27 pm
content: You don't have to remove all the old solder, just enough to get the leads of the new part on. For clearing out the hole I've used a dental pick (I guess like the toothpick and needle mentioned). I put the base of the dental pick on the bench and have the point on the back side of the board on the hole to clear out. I hold the board so that the dental pick is suspended straight vertically using only the pressure of the board (it's precarious, but avoids needing a third hand). Then I heat the top side of the hole with an iron while pushing down on the board. When the solder melts, the stainless steal pick will ram through the hole. On the flip side I used to remove through hole components in a similar manner. Clip a hemostat on the part, hold the board upside down, heat solder joints. Then the solder is melted, the weight of the hemostat pulls the part out.

author: BreakingOhmsLaw
author_rank: Frequent Contributor
timestamp: October 28, 2021, 02:47:03 pm
content: Get an "Engineer SS-02 Solder Sucker". It has a silicone tube instead of a solid nozzle. That really seals around the hole and pulls the solder out. Never fails me if used correctly.You get two inches of spare tube with it that you can cut off and replace it with.https://www.engineertools-jp.com/ss02The only issue I have with it that is is on the small side. That's good if you need to cram it in awkward positions, but if you have shovel hands it is a bit fiddly.EDIT:For the really tough annoying cases like ground planes that pull the heat out, get "ze secret weapon":SN42/Bi58 bismuth solder wire. Oh baby. It drops the melting point of solder to ridiculously low temperatures.Works like a charm, just don't use it on anything that gets hot during use, it'll unsolder itself even if minimal traces of bismuth are left in the final solder joint

author: Shock
author_rank: Super Contributor
timestamp: October 28, 2021, 08:30:38 pm
content: To clear solder blocked holes use fresh leaded solder and flux both sides then a solder sucker. If it's stubborn heat from one side and suck from the other. A small amount of residue is fine if pin/leg insertion is possible.

author: pharaoh3
author_rank: Contributor
timestamp: October 29, 2021, 04:14:29 am
content: I have no idea what brand. It's some Chinese stuff. I am using some Chinese solder that's supposed to be 60/40. I've noticed on some joints I have a hard time apply the solder.The wick I have seems to do a decent job, but it doesn't help with this issue. The best solution I've noticed so far is apply solder and removing it about 15 times, but that is incredible time waster. I was able to disassemble a broken controller today and desolder the components in under 10 minutes, but I got stuck on a single joint for hours. I think I fried the board too cause now it won't turn on.

author: pharaoh3
author_rank: Contributor
timestamp: October 29, 2021, 04:15:50 am
content: Quote from: Martian Tech on October 28, 2021, 04:02:35 amI actually do this and it isn't effective on these joints for some reason. This is why I'm tearing out my hair.

author: pharaoh3
author_rank: Contributor
timestamp: October 29, 2021, 04:17:36 am
content: Quote from: Psi on October 28, 2021, 07:37:43 amHow can I tell if it's high quality? I just order random Chinese shit off ebay and hope it arrives.

author: pharaoh3
author_rank: Contributor
timestamp: October 29, 2021, 04:24:45 am
content: Quote from: DavidAlfa on October 28, 2021, 08:51:51 amWhat's ROH solder?Also, what are the non obvious signs that a board is damaged? I was completed a swap on a practice board, but it won't turn on, and I don't see any obvious signs of damage.

author: pharaoh3
author_rank: Contributor
timestamp: October 29, 2021, 04:35:02 am
content: Quote from: ataradov on October 28, 2021, 01:15:53 amAre you inserting the tooth pick while the iron is on or are you swapping them out?I'm having a hard time getting the solder molten on that joint. It seems to glob together instead of getting molten and liquid.I asked this of somebody else too, but I want to hear your opinion. I sucussfully swapped on the joystick on a different board, but now it won't turn on? Did I fry the board? There aren't any obvious signs of damage.I cleaned the board before taking the picture.

author: ataradov
author_rank: Super Contributor
timestamp: October 29, 2021, 04:45:26 am
content: Quote from: pharaoh3 on October 29, 2021, 04:35:02 amAt about the same time. You melt the solder, move the iron slightly to the side and insert the toothpick.Quote from: pharaoh3 on October 29, 2021, 04:35:02 amNot enough flux or too low temperature. Or you are doing something else wrong. Hard to tell.

author: pharaoh3
author_rank: Contributor
timestamp: October 29, 2021, 04:51:32 am
content: Quote from: ataradov on October 29, 2021, 04:45:26 am

author: ataradov
author_rank: Super Contributor
timestamp: October 29, 2021, 06:07:15 am
content: Quote from: pharaoh3 on October 29, 2021, 04:51:32 amThis happens to pins connected to the ground plane. Even with thermal reliefs, they still "feel" different and absorb more heat.

author: semir-t
author_rank: Regular Contributor
timestamp: October 29, 2021, 06:37:37 am
content: When this happens to me, I sometimes do the following:1. I hold the PCB with left hand2. I hold the soldering iron with right hand and I am heating the hole that has solder in it3. When the solder is in liquid state I start moving the PCB and soldering iron (while still trying to heat the hole with solder in it) in one direction (as fast as possible) and then after 10-20 cm I instantly stop. The idea is that inertia will cause solder to exit the hole.This sometimes works for me and sometimes it doesn't but it's worth a shoot.

author: Shock
author_rank: Super Contributor
timestamp: October 29, 2021, 07:24:56 am
content: I know at least 20 ways to fix this but it would be a book and likely solved by my previous post and using "name brand" solder like Kester, Loctite (Multicore) or any well established non chinese brand. Inferior alloys, flux, plus unregulated and potentially dangerous contaminants are used in low cost and counterfeit products.

author: djsb
author_rank: Super Contributor
timestamp: October 29, 2021, 11:28:39 am
content: Decent solder braid I use.Goot wick: Available in various widths-Expensive but VERY good-made in Japan.Techspray: Used some that was included in a ChipQuick kit.Multicore: You can buy this in large reels, so works out cheaper.A proper desoldering handpiece is the best tool for this job. That is, providing you can find a bit with the correct size hole that accommodates the stub of the component lead.The engineer desoldering pump is also very good.Also, a soldering Iron with the heating element as close to the soldering joint as possible is best. I use a PACE MBT 350 that has the heating element in the actual bit. Metcal stations also use this approach, although the temperature is not variable like on the PACE.

author: DavidAlfa
author_rank: Super Contributor
timestamp: October 29, 2021, 12:25:00 pm
content: I'm tied to Chem-Wik, USA brand. They have tons of flux, the solder flows like a river on these.I usually buy 15 or 30m reels in eBay for around 20euro.They last a long time and the cost/meter is actually cheaper than any crappy chinese brand, they all suck, but not solder!Search Chem-wik or Chemwik (the results vary quite a bit).It doesn't degrade over time, I'm finishing my current roll after 3 years, it still works like new, no special care, no air-tight storage, I just throw it away when I'm done!They also have 500ft (150m) rolls, that's crazy!

author: perieanuo
author_rank: Frequent Contributor
timestamp: October 29, 2021, 03:41:32 pm
content: Quote from: ataradov on October 28, 2021, 12:52:06 amindeed the toothpick never will be obsolete. or some good pump after you got how it works, +- silicone tube attached or not.never guessed the toothpick thing gets out of eastern europei thought it's our registered patent

author: ataradov
author_rank: Super Contributor
timestamp: October 29, 2021, 03:53:13 pm
content: Quote from: perieanuo on October 29, 2021, 03:41:32 pmI'm originally from Russia and learned about the toothpick from my dad

author: perieanuo
author_rank: Frequent Contributor
timestamp: October 29, 2021, 04:26:18 pm
content: Quote from: ataradov on October 29, 2021, 03:53:13 pmme,when i was almost 40, in france, from a romanian pcb designer, he had crappy de/soldering tools (i had to convince him to buy hotair station and some other common-sense tools for r&d lab, the guy soldered his bga's in hungary at his friend's company)

author: pharaoh3
author_rank: Contributor
timestamp: October 29, 2021, 11:16:12 pm
content: I'm convinced its the solder that is used on the PS4 Controller. It seems to clump together much more than other solder I have seen. Plus when I dilute it with 60/40 solder it tends to clump, but when I use lead free I have no issues. However, it is very difficult to remove.Today, I replaced the joystick on my Xbox One controller, and it was incredibly easy in comparison to the PS4 controller.

author: Mario87
author_rank: Frequent Contributor
timestamp: October 30, 2021, 01:20:22 pm
content: If you want to make your life very easy, get some low melt solder. It's pricey, but you don't need much. Add some of that to the hole, then heat it up and use wick to remove it / clean the hole.The issue will be that these holes are likely connected to internal and possibly external GND layers that are absorbing a lot of heat. If you don't have a good iron that can maintain temperature, you will have this issue.As someone else said, there are many, many different ways to skin this cat (de-solder gun, de-solder pump, heating with hot air & iron simultanously, using a needle / toothpick, etc, etc). However, by far the easiest is to reduce the melting point of the solder so that the wick can readily absorb it before it cools down and hardens.As such, some low melt solder will do the job just nicely.

author: pharaoh3
author_rank: Contributor
timestamp: October 30, 2021, 02:10:03 pm
content: Quote from: Mario87 on October 30, 2021, 01:20:22 pmAll right mate! I am getting a de-solder gun and low melt solder! I'm tired of letting this problem defeat me!

author: djsb
author_rank: Super Contributor
timestamp: October 30, 2021, 07:01:08 pm
content: With the low melting point solder (ChipQuik et al)you need to make sure that you are able to remove it all from deep within any plated through holes. I've only ever used this solder on surface mount parts.

author: abdulbadii
author_rank: Frequent Contributor
timestamp: October 31, 2021, 01:01:26 am
content: ensure solder is molten & the fluxed fine wick hot so that can get wetted smoothlylikely it's not such adequate heat due to it's drained by other massive metal/conductor

author: geggi1
author_rank: Frequent Contributor
timestamp: October 31, 2021, 08:09:09 am
content: Solder iron and sucker would work well on this board for the through the hole pads.Sett up the PCB vertically with a small vice or something similar.Heat the solder pad on one side and hold the sucker on the opposite and suck out the solder when it flows.

author: grendle373
author_rank: Contributor
timestamp: November 02, 2021, 08:06:21 pm
content: "Chip Quick" low melt solder makes quick work of these. Be sure to get it all off though, I like to resolder with kester 44, then wick that, and you should be good to go.

author: nigelwright7557
author_rank: Frequent Contributor
timestamp: December 24, 2021, 10:45:13 pm
content: I have a solder sucker wit ha hard plastic tip.The hard tip isnt good for a seal so I put a short piece of soft silicon tubing over the end and that seals much better.Put solder in hole, heat up with iron, remove iron and quickly move in with solder sucker and suck.

author: abdulbadii
author_rank: Frequent Contributor
timestamp: December 25, 2021, 12:09:52 am
content: Use clean desoldering ironUnclean one won't work as heat is dismissed to many metal area else including the solder inside the toolit should work unless target point is contacted to massive conductive plate

author: BrokenYugo
author_rank: Super Contributor
timestamp: December 25, 2021, 04:27:39 am
content: Quote from: semir-t on October 29, 2021, 06:37:37 amWorks better if you run the board into something, I usually use a roll of solder. Just hold the board a few cm above and flick it into the "anvil". If you cut a part off the board this will usually knock out cut off chunks of component legs too.

author: geggi1
author_rank: Frequent Contributor
timestamp: December 25, 2021, 10:28:43 am
content: This kind of problems is normally pretty simple to solve.1. You need some kind of clamping to hold the PCB in posisjon this will free up your hand and make you able to work two handed. the clamping can be a small vice, G-clamps, "third hand" device or something similar.2. Then you need a solder sucker pump of some kind. This can be some of these cheep piston things with a spring inside just be sure to get one with PTFE tip.3. Decent solder iron no less than 50W and temperature control. Stannol type is better because there is more mass in the head and this will prevent the temperature from dropping. Weller solder stations is not so good because the small head.4. set the PCB up in your preferred clamping.5. heat your solder iron to +400C and put a good bob of solder on top of the solderpad. The bob should cover the pad and be 2-3mm high. Keep the solder hot with the iron.6. use your piston sucker from the opposite side of the PCB and clean out the via.7. clean the pad with solder-wick if required.The most important when cleaning vias is good solder, high temperature and use two hands.A tip about these piston suckers. use some wd40 or similar penetrating oil inside. the cleaning will be simpler.

author: djsb
author_rank: Super Contributor
timestamp: December 25, 2021, 10:40:39 am
content: If you're using 400 degrees C on your iron, be prepared for your pads lifting or damage to the board substrate, or both. If you are de-soldering a large earth plane without reliefs then a high temperature is justified. However I would not go above 300 degrees C. What's important is the rate at which heat is transferred from the heating element to the joint. I use a PACE iron where the element is actually in the bit itself, so heat transfer is very quick. Likewise with a Metcal (apart from the fixed temperature).

author: Ian.M
author_rank: Super Contributor
timestamp: December 25, 2021, 11:01:25 am
content: *DONT* use WD40 or penetrating oil to lubricate your solder sucker unless it has absolutely no plastic parts under spring load, as you risk it micro-crazing the plastic parts due to poor chemical compatibility, and as a result, your solder sucker violently disassembling itself during use! Instead, use light silicone oil, which you may already have around: e.g. DOT 5 brake fluid or silicone copier/printer fuser oil, which has much better chemical compatibility with nearly all plastics (excluding silicone rubber, but your sucker shouldn't have silicone O rings as they get torn up too easily by solder dross). See my comments here:https://www.eevblog.com/forum/reviews/upgrade-the-o-ring-of-goot-soldapullt-desoldering-tool/and also my suggestion for a wiper to reduce the amount of solder dross that reaches the O ring, increasing the maintenance interval and improving suction in reply #16 here:https://www.eevblog.com/forum/repair/de-soldering-advice-loosing-my-mind/The rest of that thread is worth a read as well.Here's a picture of the wiper mod for solder suckers that us a compression spring in the chamber. A waxed paper wiper disk can be seen bottom left and also several between the spring and the plunger. Sorry its such a crappy photo!

author: m k
author_rank: Super Contributor
timestamp: December 27, 2021, 04:07:34 pm
content: Why big iron and manual sucker is not a norm?The case seems to pretty always be a lack of heat and/or speed.Back in the day when CRT was a thing and horizontal deflection high some joints didn't like it at all.Finally solder compound changed totally and became something that didn't melt.Drilling wasn't an option so repetition was all that was left.Then finally you just give up and decide it's clean enough.We had rules of course and some parts had to be scrapped but for VT100 and friends there were no rules, or one, make it happen.(obsolete stuff, no new parts, or was but astronomical price, manufactured(late '80s) on your request)New solder was a key then.Now it's more accurately new flux.I've never tried pulling stuff out slowly, if not lifting a leg, but pushing it down many times.There I've used normal copper wire and two irons, old tip with hooked top will help.My desoldering iron is set to ~360C, no idea what it really is.You're also supposed to heat the joint and not the board, so as big a tip as is practical is the way.If you must touch the board with the iron remember that dry board will take the heat, so to speak.