Step 8: Desoldering, fixing mistakes and extrapolation

Desoldering is the process of removing solder at a joint to disconnect two components, wires or materials. You might have to do this if you want to replace a component that's gone bad, or if you want to change something about your design once it's already soldered into place. To desolder wires you can usually just heat up the connection and wiggle them around until they come free. Better yet, if you have the slack, just cut the wire at the connections, strip, and resolder as necessary.

With leads that are mounted through holes on a circuit board it takes a little more finesse. To desolder something delicate its best to use a desoldering pump, or bulb which will actually suck up the molten solder and remove it from the joint. Soldering wicks or braided copper wire also work well to suck up unwanted solder. For more complete guides on desoldering check out Make Magazine's Learn How To Solder Skill Building Work Shop Video and this site here.

Fixing mistakes:
Soldering is pretty forgiving, and its usually pretty easy to fix a mistake. If you put down a little too much solder or position something incorrectly you can usually reheat your joint, melt the solder, and then reposition your component as necessary. Solder can be heated and cooled as many times as you need to get your joint the way you want it. So don't be discouraged if it takes you a couple of tries to get it down - you will still end up with a good connection if you stick with it.

Soldering is a pretty straight forward process but there is no limit to what you could create with it. Try to join things together. It works well for making jewelery, doing basic arts and crafts with small metal objects, or re-wiring your toaster into a heating element for an infra-red sauna. If soldering has been keeping you away from experimenting with circuits or making a project, hopefully it doesn't have to anymore. Once you do it a few times you might even start to enjoy it.

If you would like to get started on a few basic soldering projects check out instructables user Makekits and the Make Magazine Store to build things like a MiniPOV or a Daisy MP3 Player.

<p>Thanks for explaining things so clearly! The whole article has given me a great insight and also explained where I had been going wrong in the past.</p><p>I will leave the desert island survival tips alone for a while, but its good to know just incase!</p>
<p>Thanks for the guide! I also wouldn't recommend stripping wire using teeth. Some plastic wire insulation can contain lead. Here's a CDC account of someone getting lead poisoning from chewing the plastic: http://www.cdc.gov/mmwr/preview/mmwrhtml/00020984.htm</p>
<p>More of a problem with biting the insulation would be chipping your teeth, as I have done over the years of removing insulation that way.</p>
<p>He chewed the plastic wire coating for 20 years and has a slight lead poisoning in the article. That's a huge difference from biting off the tips and spitting them out. </p><p>Lets not go overboard comparing apples to planets.</p>
<p>You shouldn't twist the wire. You don't need to and its amateurish. You should just position the two wires parallel and solder them that way. That way you can make a nice tight joint and can easily fit heatshrink sleaves over the joint. Regardless of what people might think.. twisting the wires together does NOT make for a better joint. The solder is more than enough to take any stress from the wire being pulled or twisted afterwards. It does not need to be twisted together beforehand. </p>
&quot;Don't know if it can be soldered? Give it a try - you won't blow anything up.&quot; I have a stick of dynamite that I want to attach to something, can I solder it?
<p>Hi I've just finished a little soldering project but unfortunately its not working, I've just read your comment about not reheating solder, which I think I did a few times, how crucial is this and could this be the reason my circuit won't work? do you think I should start again? Thank you</p>
<p>@<a href="http://www.instructables.com/member/sjones98/" rel="nofollow">sjones98</a> Hey there. Fixing that wouldn't be a problem. I've reheated solder many, many, many times on the same project while I was learning and I never had an issue. It cleans easily, remelts cleanly and often looks 10x better when I'm finished. The best advice I could give with regards to fixing your soldering is to do one small area at a time. Reheat the solder and wick most of it away, make sure you are using the right kind of solder. Find some that is specific to electronics. It will have mostly a silver base as opposed to lead and is very thin. A thin point tip on your soldering iron will help as well. It keeps the solder neat and reduces the solders habit of spreading to other holes.</p><p>When you are ready to resolder your board, only use a very tiny amount of solder. It takes barely any to make a nice solid connection. It's human nature to want to gob it in, because more is better right? In most cases, no. Just a dab will suffice. The right amount will surround the pin and be barely larger than the hole.</p><p>I hope this helps! Cheers.</p>
<p>I see that this is a bit late but the problem seems to be the soldering done on the board. There are a few areas where leads seem to overlap, which, of course, causes short circuits. I'm not the greatest at soldering myself, and I've done worse quite a few times; sometimes involving unpleasant explosions. </p>
<p>FLUX...the secret of flow</p>
<p>Step one: Find a man. </p>
<p>One very undersold product at the Shack was the Velleman kits. I've done a couple of them, and they seem more like useful items than the Arduinos and Bone stuff. For example, Velleman had a USB breakout kit you could build that gave a variety of real world contact closures and sensors out... and in. I have a couple of them going in a remote control project or two where you can uVNC to a PC somewhere, and turn things on and off, take readings, and so forth for equipment nearly a hundred miles away. I didn't have to learn an entire micro-language or buy/build complex processors, masks, and all that like it appears i would have to with Arduino. I dunno about the rob you clean bit... I'm old enough to think of names like Heathkit, Archer, Optimus, Uniden and the like in Radio Shack stores. Yes, sometimes expensive... but nearly always rebuildable and nearly all that stuff I've bought over the years is *still* running.</p><p>Like my Optimus 100X6 Tuner Amp. yup. 6 big transformers in it and it drives 15&quot; drivers to about 128dB @ 35 - 12k frequencies.</p>
<p>great instructable. thanks!</p>
<p>RadioShack may rob you clean most of the time but I've had a pretty good experience with them about a year ago. We were writing business letters in my English class, and we could send them to a business of our choosing. Running out of ideas I chose to send to RadioShack. About a month latter my English teacher told me that a package from RadioShack was sent to the school to me. So I got the package, and inside it was a letter saying how they appreciated a young person being interested in electronics and DIY. Also inside was an Arduino Mega 2560, Skull Candy earbuds and a radioshack T shirt that isn't available in stores. The letter was handwritten, and signed by about 1/4th of the mail dept. Ever since then I've had respect for the store.</p>
<p>As a soldering instructor, the one thing I see often is people not knowing about the importance of FLUX. If your solder is balling up, not flowing where you want it, not gripping the wire, pad, or component, its because you did not use flux. The rule is that &quot;solder follows flux&quot;. When flux is applied, and heated with the soldering iron before applying the solder, it does several things. It creates a thermal coupling to transfer heat quickly to the area you will be soldering, it removes and impurities and oxides that are on the metal surface, and it prepares the metal to bond with the solder. If you apply solder without flux, it can be easily removed by chipping it off or by vibration. If you apply flux first, your solder joint permanently bonds with the metal. It cannot be chipped off and even heating it again and wicking the solder off will leave the surface coated with solder because the solder is permanently bonded with the with the metal. For electronics, the recommended flux to use is RMA, which is a mildly active acid flux. It becomes active only when heated and the acid etches the metal allowing the solder to bond to the etching. Be sure to quickly clean the flux residue off and clean the solder joint.</p>
<p>Nice work! Very detailed.</p>
<p>great instructable. thanks!</p>
Hi, this &quot;through hole component&quot; soldering is exactly what I've been trying to do. The DC jack on my laptop is broken, and I've been attempting to fix it. But for the life of me, I can't get the solder to behave the way yours does in the video, where you get the &quot;ant-hill&quot; shape. <br><br>When I do it, the solder either balls up on the end of the solder wire, or bunches up into a little blob around the lead, which is only a good enough joint to last for a week or so before I start losing the connection again. (I had the exact same problem while I was soldering the pickups in my guitar as well, although that was soldering a wire to a plate so it was quite different.)<br><br>So can somebody please tell me....WHAT am I doing wrong??
<p>I would check that you have a soldering iron that will heat up high enough first. It sounds like the components you are attempting to solder never get to the proper heat to allow the solder to flow. Heat is crucial. To much and the solder is not controlled and to little it will not stick to the components. Make sure you are applying heat to the component you are trying to solder and not the solder itself.</p>
Ive had this problem myself and have found it to be that the contacts you are trying to connect are dirty and you probably need to flux them. <br> <br>Hope this helps
Just a guess but you may be trying to solder lead devices with lead free solder and equipment. I don't have any experience with the lead free stuff myself but I hear it is hard to work with. Maybe someone else can shed some light on this?<br> <br> I cannot see what you are doing but it sounds to me like your iron tip is not tinned properly, or it was, and it is dirty now. Something like that. Take a paper towel fold it into a little square and soak it with clean water, then wipe your hot iron tip on it with a rolling motion a few times see if you can make it shiny bright.<br> <br> You should be able to get a droplet of solder to stick right to your iron tip. If you can't do that you can't solder. Well, not you can't solder, just you can't solder with that iron tip.<br> <br> When you solder to a metal plate it is helpful if you sand the smooth metal with emery or sand paper to put some scratches in it that the solder can grip to. Solder won't stick to all metals either. Like you can't solder aluminum. Well you can solder aluminum, just not with regular solder.<br> <br> Confused yet? Good! I think that is how they want us to be.<br> <br> Insist on genuine lead solder!<br> <br> <a href="http://i.imgur.com/l1z0g.jpg">http://i.imgur.com/l1z0g.jpg</a><br>
<p>Great guide for beginners. Thank you for doing this</p>
what should we do if we want the melted solder completely removed from the circuit board altogether? you mention some sort of pump, but that sounds REALLY exspensive and convoluted, when there is probebly a much easier way.
A less scary term for a desoldering pump is a "solder sucker." They aren't any sort of complicated pump for fluids, and can be as simple as a little rubber bulb with a plastic nozzle coming off of it. The ones I prefer are tubes with a nozzle on one end, a plunger in the other and a spring inside to push the plunger out quickly, sucking the liquid solder in through the nozzle.
<p>In my experience solder wick works better. Put the wick on top of the &quot;boo boo&quot; and apply your soldering iron. You may have to move down to fresh wick and apply heat again to get all the solder. I have heard that braid from coax cable can also work for this although I have never tried it.</p><p><a href="http://www.radioshack.com/product/index.jsp?productId=2062744&cid=ip%3Asem%3Arso%3Agoogle%3Abent_soldering_tip&stop_mobi=yes&utm_campaign=RSO_SRC_EN_NCA_NB_B_Hobby_Do_It_Yourself&utm_source=google&utm_medium=ppc" rel="nofollow">http://www.radioshack.com/product/index.jsp?produc...</a></p><p>Available at RadioShack although probably cheaper elsewhere. </p>
Have a hunt for 'solder wick' or a desolder pump - that will do the trick and is extremelly cheap! Even Maplin sells it!<br/><br/><a rel="nofollow" href="http://www.pcbpolice.com/">PCB Police Electronics Forum</a><br/>
do they last forever?
So, how does one use 'wick'? is it the obvious just wipe up the solder with it? or maybe there is a long convoluted ritual involving worship and dance steps, even voodoo!?
If the "wick" is anything like a desoldering braid, then you usually just lay it across the join you want to remove solder from and heat the wick up, the solder will just flow into the braid like you were tinning a wire. In general, I've had much better luck with braids than solder suckers/pumps.
thanks kitsune and franklin i found out how to afterward, online, but i still appreciate the answer and yes, i've learned there is different wick for leaded and unleaded solder and they aren't interchangeable thanks again
radio shack braid only works on leaded solder it worked fine for me but some kid who was using lead free(for school, i brought my own solder) and it didnt work
desoldering pump/iron combos are less than 15$ at the evil ones (radio shack)
<p>O.k., I didn't read all of this because of time constraints, but I'm really anxious to to so. If there is one thing I'm lousy at is soldering. I'm lousy at a lot of things, but this is a pain in my neck. I have one of those cold soldering guns that you can touch and won't get burned. Will your system work with them? I can't get the darned thing to work. See, I'm lousy at this stuff. I have regular soldering guns, too, and am geeked to get them do what I want. Thanks in advance!</p>
<p>The biggest mistake people make soldering is they fail to clean what they are trying to solder before they solder it. Everything involved with the soldering process has to be bright, and shiny before you solder. Dirt, oxides, and oils all need to be removed from whatever you are soldering prior to trying to solder it. Emery cloth, Scotchbrite, steel wool, or a wire brush may be used to clean, and brighten conductors prior to soldering them. A solvent may be appropriate to use too. Soldering iron tips should be wiped off immediately before using them to solder a joint as well.</p><p>Make sure your soldering work is soundly mechanically connected before you solder it too. That way the joint will remain immobilized until the solder solidifies. Other than that feed solder into the joint, not the iron, and it should all work.</p>
I bought a 30W soldering iron from Radio Shack. I'm having a lot of trouble because it takes as long as 90-120 seconds for the solder to heat up. And if I don't touch the solder directly to the iron, it never gets hot enough at all. Plus, the solder doesn't flow well and it turns into balls & blobs. I'm puzzled. What's wrong?
I know this is an old post, but someone may benefit. <br>There's a few possible problems, the obvious one is you're iron isn't hot enough. I prefer a 40W iron over a 30W any day. It seems 30W are the most common, but they just don't cut it for me. <br>Try a cheapo model form ebay etc for $5 or so and see how it works for you. <br>Another fix is to heat the iron up a bit with a torch. I rarely need to do this to boost heat, but I will use a torch as the heat source for the iron if I'm too far from an outlet.. <br> <br>The other problem could be thinking the flux inside the solder is enough. It is not.... At least it has never been for me. You need to flux the surfaces and be sure the surface can be soldered in the first place. <br>The surface could be coated or plated with something that either the solder or the flux doesn't like. It might also be corrosion, a lubricant, protectant, or who knows what. In those cases I clean it with a chemical such as electric contact cleaner aka brake cleaner, or even carb cleaner, but most people use alcohol. If that doesn't work then it's probably some kind of coating you'll need to remove with force, like sandpaper or a Dremel tool to break thru to the good metal. Once you've ground the bad part off, clean it, coat it with flux and try again. <br>If it's still being difficult you can try using sandpaper on it while it's coated in flux. I like 320-400 wet/dry paper, maybe 180-220 if it's really bad. Cut a small piece for sacrifice because you don't want to use it again now that it has flux on it. After you have either roughed it up nicely, or ground thru the problem coating whatever it was, clean it, flux it, and try again. <br>I prefer to coat the problem item in solder first, that way I know it'll work when it's time to attach something. Assuming the iron is hot, clean, and will hold solder (plain old rosin core 60/40 works best for me), put a little on the tip, then apply it to the surface and hold until it flows and coats your surface. If it's a large item and you can't get it hot enough you will need to preheat the item with a torch or whatever, I've used anything from little butane torches to my oven, as long as everything can handle the heat that is. (fyi; preheating also works for welding when the machine can't generate enough heat). Once it's hot enough the solder will flow nicely into the area worked on, and your problem is solved. <br> <br>If you never could get the solder to stick then you might be working with the wrong metal, like aluminum, so use the appropriate method for that metal, or simply try using a screw or bolt as a contact. If you can figure out what the base metal is, then search the net for a bolt material that will not react with it. Example; drill a hole and use an appropriate bolt/nut and torque it down good, then apply solder to the bolt's head which should be a snap. Common steel bolts are usually coated with something which probably needs to be ground off. Grind off just enough area for what you need, and preferably solder it in a way you can still use the tool to remove it if needed. Now flux your spot and apply a little drop of solder like described above. Being a bolt it's probably heavier and may need a little boost with a torch. <br>I flux/solder each piece first so I know they're both good to go, then I put them together and add a drop of solder with the iron until it flows. <br> <br>I hope this helps some people with their soldering problems... <br>
<p>Chevota</p><p>I would probably avoid using brake cleaner then applying heat, because depending on the formulation you can emit phosgene gas:</p><p><a href="http://www.advrider.com/forums/showthread.php?t=488740" rel="nofollow">http://www.advrider.com/forums/showthread.php?t=48...</a></p>
<p>Thanks, something to think about. I don't think you can buy that kind of brake cleaner anymore, plus it evaporates almost instantly when cleaning stuff like that. I do remember spraying the older stuff on something red hot and the smell was horrible. Not sure if it was that particular gas, but omg it was bad! </p><p>Speaking of solder, I lost my old solder and flux in a move so I bought this new solder and flux, some &quot;safer&quot; crap or some bs but it was all I could find. I haven't been able to solder anything but clean copper wire and that barely sticks together and often fails. It's horrible stuff. Maybe that was the original posters problem? I guess I'll have to buy some from china on ebay or something. </p>
<p>Lead free solder melts at 218 deg C where leaded melts at 183 deg C. You may need to get a higher wattage iron to work with it. That thanks to the EU which started this lead free mess.</p>
<p>I've always preferred a higher heat than what most people use, for example I won't use a 30w, only 40w at min. I don't know the exact temp but to get the same effect from the adjustable solder station at work I need 800F/426C. Others at work used 700-750F and they struggled. This was back when we used real lead and flux btw. So I don't think 218C would work at all, but whatever the case I'm well above it. I've even tried boosting the temp by heating my iron with a propane torch, but it doesn't help. My latest project needed tabs soldered to rechargeable AA batteries to renew a cordless tool batt pack. I've done this in the past with lead 60/40 and acid flux no problem, but the new stuff refuses to stick to the batts. It's like trying to solder to glass... Very frustrating. My flux might be part of the problem so I will look for a different type. I may have to spot weld the tabs like the factory does, but it doesn't help me with other stuff. </p>
<p>sand the battery contacts, and make sure the battery is getting hot enough. it's a very difficult thing to do, getting something like that hot enough without getting it too hot. also, reheating it over and over, trying to get it right, will probably negatively affect the battery life and capacity. practice on one set to know exactly what you need to do, before moving on and doing it right on all the rest.</p>
<p>Yes, I have done this many times for decades on all kinds of projects with no problems. Then I lose my old 60/40 lead and &quot;good&quot; acid flux and have not been able to solder a single battery since. I plan on trying spot welding next, unless I get lucky and find my old solder &amp; flux. This new solder makes everything much harder btw, but it made the battery thing impossible. </p>
<p>A soldering iron is nowhere near hot enough to convert a chlorinated solvent to phosgene. Think arc welding or oxyacetylene temperatures.</p>
<p>Someone brought that part up because I said I used brake cleaner to clean parts that have grease/oil on them, then if the part is too big for the iron to heat you can preheat it with a propane torch. Not so much about the part getting too hot, but putting a torch on a the surface still wet with cleaner. Not a common circumstance, nor do I believe most cleaners sold today are an issue, but something to consider. Plus if you do manage to create the gas, which I think I might have once or twice, it's too nasty to breathe anyway. </p>
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<p>my molten solder sticks to the soldering iron</p>
<p>clean it off extremely well, by tinning it and wiping it on the sponge. multiple times, if necessary. </p><p>or, you may simply not be getting the material hot enough. when the thing you're soldering is hot enough it will suck the solder off the iron. if you've never seen it, you may not believe it or be able to imagine it, but i promise you, it's like a sponge touching the edge of a water droplet... the solder literally gets sucked onto the metal when it's hot enough.<br><br>also, your iron may not be capable of getting hot enough, if it's really old or if the tip is damage in some way. if the tip is damaged, you could just replace it and see if that works. if the iron is so old it doesn't heat up enough, you'll just have to replace it.</p>
The iron I have is 20-140 watt. It also has quite a big tip so is this not as good for circuit boards? And also I always thought you had to tin the tip before and after using it. Is tinning it too much bad for it? Thanks
<p>the big tip can work if you're careful. just don't allow it to touch anything other than the metal you're soldering. </p><p>i tin my iron every time i use it and possibly multiple times while using it, if it stays on a long time. once it heats up, tin it and clean it off on the sponge. it needs to be shiny. if it has discoloration, or isn't shiny, re-tin it and clean it off again on the sponge. through usage, you'll probably be getting plenty of tin on it, so you'll just need to clean it off every once in a while, but if it sits in the holder for a long time while hot, you will probably need to re-tin it and re-clean it before usage.</p>

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