9 Different Desoldering Techniques

by Proto G

147K74682

Intro: 9 Different Desoldering Techniques

In this instructable, I'll show you 9 different methods for taking electronic components off of circuit boards. Whether you're repairing boards or salvaging parts, it's a necessary skill. This video quickly shows 4 methods.

STEP 1: Solder Pot Salvaging and Other Brute Force Methods

This first technique is the most destructive and should only be used when you do not plan on keeping the board. I use this method to salvage a lot of components at once. I have a drawer that I keep scrap PCBs and every once and a while, I'll salvage all the parts from them. I find it very therapeutic and relaxing to remove all the components off of a board.

You can coat the bottom of the PCB with flux to speed things up a bit, but it isn't necessary. After that just use tweezers hold the board over the solder pot and use pliers to remove all the parts you want.

A good alternative to this method is using a small butane or propane torch to heat the bottom of the board up while pulling components off with pliers. Even better if you have a bunsen burner with a mesh screen tripod.

If you're salvaging parts, don't be afraid to use tools to cut the board like a hacksaw or large snips.

Another brute force method is to heat the leads of the part up and smack the board down against an edge of a container. The parts usually will drop in and if not, try adding extra solder. Be sure to wear eye protection because you do not want molten solder in your eye.

All of the desoldering techniques shown in this instructable should be done in a well ventilated room as well as with a respirator if you are going to use a flame to desolder components.

STEP 2: Manual Solder Sucker

A good manual solder sucker like this one works pretty well for selectively removing through holes parts from a PCB. Cheaper and smaller units do not work as well. They're marketed as compact but they don't works as well due to the limited stroke length and smaller cylinders.

STEP 3: Solder Wick

Solder Wick is basically just copper braid that soaks up solder when you heat it up. Good solder wick should always have flux in it. To use it, simply hole it up the the joint you want to remove solder from and hold a soldering iron up to it. It should soak up the solder fairly quickly. If not, then you probably have poor quality solder wick. If you do, you can doctor it up with some flux like this. Just add flux to the portion of the braid you'll be using before you put it on the joint. You can also add fresh solder to the solder joint beforehand to help a bit if the joint does not have a lot of solder to begin with.

STEP 4: Desoldering Machine

If you repair a lot of boards, you absolutely need a machine like this. It is basically a soldering iron with a hole in the center of the tip that is connected to a vacuum pump. Just hold it up to any soldered lead and watch the solder suck right up. I can't recommend them enough.

STEP 5: Hot Air Rework Station

For desoldering a lot surface mount components at once, a variable temperature hot air rework station is the best tool you can use. If the board is completed filled with surface mount components, you can just squeegee off all the parts when the board is up to temperature. They use have different tips for different types of components.

You can also use a regular hot air gun but be careful because you can damage other components and the board.

STEP 6: Desoldering Tweezers

For selectively removing surface mount components, these heated tweezers are great. Once they get up to temperature you just pluck up the components off the board.

STEP 7: Hot Plate

A heavy duty electronic hot plate like this, can be used to heat boards up to soldering temperatures and if you don't have one, I have even seen some people use a pan on their stove to remove components.

STEP 8: Compressed Air

For this method, you should definitely make sure to wear eye protection. You use a soldering iron to heat the joint up and then use a can of compressed air to blow the solder off. This is rather messy and I would only recommend doing this on a board that you are salvaging parts from because you can end up with solder where you don't want it. It is rather crude, but it works.

STEP 9: The Hard Way

If all you have is a soldering iron and some solder, you can still remove parts, it's just much harder than all the other methods I've shown. Adding fresh solder to the joints is really your friend here. It will really help when trying to desolder components with three or more leads. Sometimes it's hard to heat them all up fast enough but adding flux and a good amount of fresh solder to connect the leads will speed things up. There are low temperate solder wires available like ChipQuik that you can use specifically use to help remove components. In place of solder wire, you can use low temperature solder paste to speed up the desoldering process even more. It is often in an easy to use syringe for quick placement.

A good way of removing surface mount IC components you know are bad is to just snips the leads with a small knife/razor very carefully. Heat up fresh solder and use a solder wick to clean up the area. Do not use snips because you are very likely to damage the pads on the board. Pushing straight down with a razor on the leads as close to the chip body as possible works great.

STEP 10: Thank You

Thank you for taking the time to read my instructable. I hope you learned something new. If you feel that I left something out, feel free to leave a comment below. I'd love to hear what your favorite method is.

If you want to see more of my work, subscribe to my YouTube Channel.

I ship out free parts to the first person that messages me after commenting on a new video. These include sensors, components and other small parts. U.S. only because the shipping is always worth way more than the parts.

70 Comments

SolidRaven 8 years ago

Good manual for hobby purposes, but you left out a few important notes I think. My apologies if the structure of my post isn't the best!

NEVER EVER MIX SOLDER ON BOARDS YOU'RE REPAIRING!!! It causes fragile solder joints that are very sensitive to thermal expansion, shock, vibration, and other effects. On boards with leaded solder only use leaded solder. On all consumer grade board since the early 2000s use lead-free solder! If you suspect speciality types (e.g. cadmium based) of solder do it in open air or don't bother with it for that matter, but these are only to be found in avionics, military, medical, and high-end test & measurement setups. Low temperature Tin - Bismuth solders are starting to show up more often since they're actually quite cheap, you can easily detect these by using a soldering iron on a low temperature and check if it starts melting around 165°C. SnBi solder in wire form is extremely hard to find, though a company called Qualitek sells it in large spools. Use a separate tip for SnBi work and label it, consider it a contamination for other solders.

Using scissors or wire cutters to remove components is quite often done, but indeed a bit risky if you're not used to doing it. Luckily there is a somewhat idiot proof method at this one. When removing large packages with pins at the side and you don't care about the component a Dremel is your friend! A good carbide cutting wheel and some careful movement allows you to cut the pins without excessive stress on the board. But be sure to clean it for metal particles afterwards! Obviously safety glasses and a mouth mask are recommended.

And hot air rework is often combined with an infrared hotplate on the 'good' (= expensive) systems. You heat up the board to about 100 - 120°C and then locally heat it up further to 250 - 280°C (or more) using the hot air. This helps prevent board wrapping due to excessive heating (which is desirable in many cases), though this does expose the component to excessive temperatures if done incorrectly! Additionally this reduces the failure rate when removing BGAs I found. (Not sure if this is a consistent trend.)

Highest component survival rate, for non-BGA/QFN/DFN style packages, on modern boards I found is using a soldering iron which is able to pump quite some heat into the board quickly (e.g. ERSA i-con stations at 380°C) and adding a lot of solder on all sides of the component, switch between the sides constantly and push the component to the side using the solder wire or a set of tweezers and just pick it up then. Afterwards you can clean the component using desoldering braid on a lower temperature. Afterwards clean up the board using desoldering braid and don't be afraid to flux the hell out of it, be moderate on the temperature to avoid delaminating the pads. Afterwards give the board a good rub with a defluxing agent and some isopropyl alcohol as final step to clean it up.

A final trick is you are really stuck with a big fat QFP you can't get rid of is to take thick copper wire (2.5mm² or thicker) and to bend it around the perimeter of the component, then bend a part of it up and stick it in your soldering iron (does void waranty though :( ) and let it heat up for a while.

In terms of soldering irons, don't buy cheap Chinese counterfeit ones if you solder often. Both Weller and ERSA are still somewhat affordable and make great tools. Especially ERSA (i-Con 1 or better, none of the nano or pico stuff) seems to be the better choice in recent years. Granted the LCD screens on their stations suck, but they're brilliant at everything else. If you happen to find yourself somewhat insane and with too much money there's always Hakko for you I suppose.

Middle Finger 4 years ago

Damn might as well right a Novel! How about heating up some sand on a baking sheet toss the board on top for quick bit than swipe, tap or hit the board & catch the components on to something! But only if your chucking the board!

SolidRaven 8 years ago

Good if that works for you! Bit curious though; how well does that one perform soldering on a thick big ground plane? That's usually the difference I've noticed between the cheap and expensive temperature controlled ones.The expensive brands are usually able to output significantly more than their rated power. (For example the small tip ERSA ones can solder on thick copper plates and seem to output nearly twice the power mentioned on the datasheet. )

And obviously the most important factor for long solder jobs is comfort, which is why I still prefer the station form factor with a fine iron. But that's personal choice more than anything else.

And wow, $400 for a soldering station...

kahurangikea 7 years ago

I haven't compared the two regarding rated power output. For bigger heat sinks I use larger tips and/or increase the temperature setting.

It was $400 New Zealand but purchased from Australia which could have been around USD $250. Our markets tend to be less competitive also.

MarcR48 7 years ago

I agree, I have two Weller stations and the cheap chinese iron is lighter and seems to work just as good if not better.

DIY-Guy 8 years ago

Love this instructable!
Desoldering is very important for saving money and practice circuits.


I have purchased some things from Banggood and would like to be able to trust them before buying a soldering iron.
Lately, items have been showing tracking numbers which are non-existent and the order is claimed to have been "delivery refused." It is impossible that I would refuse a delivery of what I've ordered!
Also finding that each and every part must be tested, for example Hall Effect Magnetic Sensors for Arduino have some bad ones arriving from Banggood.

Lee Wilkerson 8 years ago

Banggood almost always ships packages with 'signature required'. If you miss the carrier and the little pink slip, your package goes right back to it's point of origin.

I have ordered from them about 15 times in the past 6 months and have gotten all of my orders. Sometimes there is substantial savings in ordering from the non-USA stations.

DIY-Guy 8 years ago

Banggood claims "Delivery Refused" sometimes even after a package has been received by a mail service, which always accepts packages.

We're wondering why some of the suppliers working with Banggood do that on occasion and wonder if it's a credit card thing, or if they want to charge extra for "reshipping" in some cases. We've even received a package, had it show up as "undeliverable" on their site, and then have them charge us for reshipping the very package we already received.

Some accountability needs to be used in their business dealings on the China side. I'll be very glad when these anomalies stop and we can buy without fear from them. Until then, it's a calculated risk.

Proto G 8 years ago

Good points but I can't agree with using scissors, wire cutters or a dremel to remove large packages with many pins when repairing a board. Especially for surface mount packages, it is extremely easy to use an xacto knife and gently press down as close to the component body as possible. Very quick and doesn't risk damaging the pads. Scissors and wire cutters run a high risk of damaging pads. I'm sure it works for you, but I don't recommend it for a hobbyist or beginner.

SolidRaven 8 years ago

Wire cutters are hardly suitable for high pin count components, I apologise if you thought I meant that. But they do a great job for SOIC-8 packages if you have some practice with them. And I do agree the Dremel method requires a high degree of fine motor skills, but all fine Dremel work does! And for all manual methods you should probably be using a good stereo microscope to begin with if you wish for both board and component to survive.

To get back to the knife though, I found (based on personal experience) a knife has a high risk of delaminating the component pads depending on the base material and laminate lay-up. I know for example you shouldn't use the knife for the adhesive-based FCCL we sometimes use at work, you'll tear off the pads quickly, not to mention damage the copper layer underneath. Same when using RF laminates (PTFE or LCP based), never apply mechanical force on those since the adhesion between the copper/gold and the rest of the laminate is usually horrendous contrary to what the manufacturer claims. Most China PCBs tend to suffer the same problem. On the other hand if you have PCB from a good board house that uses good quality base material (e.g. Hitachi, UBE, DuPont, ...) you should be fine when using a knife. That's why I tend to discourage people from using knives to disassemble PCBs. When it's one of those conductive adhesives though, shear away with a knife. Most of them are so brittle that a good wedge in it with a knife will cause the binding adhesive to break.

Another thing worth considering is after desoldering a lot of components is applying a lot of flux to the affected areas and sending the board on a pass through a reflow oven; it'll redistribute the solder nicely and make it easier to put new components on. Don't use infrared ovens though (unless you like molten connectors), vapour phase works best for this.

(Disclaimer: I have to do these sort of things at least once or twice a week, so a lot of this comes from poorly documented personal experience. Damn thee deities of electronic circuit design!)

Lee Wilkerson 8 years ago

Great trainer instructable. Having used desoldering flux, solder suckers, heat guns, and desoldering machines, my least expensive favorite is the solder sucker. I have found that after whichever desoldering operation, removing the component in question is much easier if I use a pair of needle-nose pliers to wiggle and twist the component legs a bit to finish the detachment process.

Desoldering machines are great, but they can be expensive. If using a small tip, occasionally you must use a stiff piece of wire to clear it.

The only issues for solder suckers is that occasionally you have to disassemble the unit mid-task to clear the tip and you occasionally have to re-grease the inside of the cylinder.

Heat guns work really well for surface mount components, but you will occasionally dislodge more components than desired.

Solder flux is a pain to use because you sometimes peel traces off the board or overheat the component and/or board with it. I believe it is best relegated to the salvage category but there are more suitable methods for salvage...

I have also broken and/or cut PC boards to remove components. It's brutal but effective if you no longer wish the board to remain intact.

I've never used a solder pot.

miked2001 8 years ago

For larger through hole parts my friend used needle nose pliers and a Bernzomatic torch. worked great and fast. Just don't expect to use the raw board for anything afterwards.

Proto G 8 years ago

Yep, I mentioned that in step 1.

mondalaci 8 years ago

I love to use my ZD-985 desoldering station for this purpose. It's not as high quality as your Hakko station but it's a great bang for the bucks, costing only $110. You can find it at http://panda-bg.com/en/product/Desoldering-Station-89-8514-ZD-985-LDD/321740/ (I'm not affiliated with them, I just wanna share it.)

mgarage 8 years ago

A trick that I saw a recycling place use: Take a cookie baking tray, put about 1/4 " of fine sand in it and enough motor oil to wet the sand. Put the tray on a propane burner and heat it to the melting point of your solder +10-25 degs. Take a PCB with thruhole parts or top SMT, place it on the wet sand, press it in a little to make good thermal contact and with gloves/needle nose, start picking parts out of the PCB, it heats up quickly so work fast. This is good if you've got many boards to salvage.

ianlee74 8 years ago

There's one technique you didn't mention that I use often when in a bind and solder wick just isn't working. Simply heat up the part with the iron and give the board a swift tap on the table. The part and excess solder will fly off. You just have to be sure and clean up your board and make sure some of the solder didn't stick to it where you don't want it if your intent is to use the board again.

Proto G 8 years ago

I did mention it. I listed it as an alternative to the solder pot method in step one.

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