Bad Idea For Desoldering Actually Might Be Pretty Smart

This video on building a DIY desoldering iron says it all right up front: this is stupid and dangerous, and you shouldn’t do it. But that doesn’t mean it doesn’t work, or that it doesn’t have potential to be turned into something else.

The story begins, as it often does these days, on the pages of Amazon as [AnotherMaker] shopped for a real desoldering setup. Despite a case of sticker shock, he took the plunge on a nice Hakko vacuum desolderer, but as is also often the case, it failed to arrive. Rather than accept defeat, [AnotherMaker] purchased a cheap-o soldering iron and a brass tee fitting for small-bore tubing that would chuck nicely into the spot where the stock tip once lived, giving him a way to both melt solder and move air.

Unfortunately, rather than applying a vacuum, he chose to blast 100 PSI compressed air through the tip, which certainly moves a lot of solder, perhaps at the cost of burns and eye injuries. The potential for accidental short circuits is pretty high too, but c’mon — it’s not like we all haven’t flicked or dropped a board to desolder something. Is this really much different?

As fraught with peril as this method may be, [AnotherMaker] is onto something here. Perhaps adding a 3D-printed venturi generator could turn that blast of air into a vacuum. Or maybe a vacuum pump for a manual pick-and-place would do the trick too.

48 thoughts on “Bad Idea For Desoldering Actually Might Be Pretty Smart

  1. Okay, similar but safer(?).
    Years ago, I saw a desoldering setup that consisted of a squeeze bulb desoldering iron with a refrigerator compressor connected instead of the squeeze bulb. The air hose was connected to the input side of the compressor, in between the iron and the compressor, he had placed a air hose filter (to keep solder bits from entering the compressor). The compressor was started by a relay controller by a push button he had mounted on the iron.

    So, if your junk pile/parts bin has a working refrigerator compressor, you are halfway there.

    1. As a kid I use to use fridge compressor to power a solder sucker, it worked a charm. The compressor was picked up in a dump, so I assumed it didn’t work or was going to break, years later the system still worked. I didn’t even add a filter to the suction line, it must have pulled the solder into the chamber and only had valves on the output side. The one thing to look out for is there are lubricants in the system and if you tip the compressor, it could pump out the fluids. The system was eventually lost when my mom threw it out thinking it was what it looked like, a piece of garbage, burned chunk of metal from a dump.

    2. how much suction is actually required to pump molten solder? maybe one of those cheap eBay diaphragm pumps could do the job. connect the pump to a vacuum vessel of sorts (like a mason jar). this is on a t junction with a solenoid valve at the other end. and that is connected to a smaller catch jar with some water at the bottom to cool the solder. and that would run to the iron with some heat resistant tubing. operation would turn on the pump to depressurize the vacuum vessel, you would then heat your solder joint. then open the solenoid valve when you are ready to suck the solder. your catch jar should be full of solder beads.

      1. Mouser also has free worldwide express shipping from 50 EUR (same probably goes for the others). Amazon is flooded with contraband, returned goods and sellers registered in legislations that don´t mind the sellers issue invoices of questionable authenticity (big problem if you are a business customer). Honestly hands off amazon. If you dont care about reliability you can buy the same cram directly from china for cheaper (for most legislations).

        1. Digikey has free shipping too. They also have a Real Human who reads the email and the little web chat window. Very useful. Element14 have been good in this regard too, their web chat people have helped me out a few times to identify parts from my photographs. I would prefer to give my money to businesses like this than some dropshipper on the Bezos barn :-)

    1. I would have replied to you on mobile, but all 3 of those companies’ websites are such abominations on mobile, I couldn’t really check.

      Mouser and Newark don’t sell the FR301 and it’s $80+ more expensive on DigiKey. If you need any more clarification, let me know

  2. Thanks for the write up. The Hakko came in and it’s a wonderful tool. This thing really is great for salvaging parts and it’s impossible to clog.

    Stay safe out there

    1. I used one and was really impressed, so I talked my boss into getting a Hakko air-powered solder vac station to replace the aging, weak Weller solder vac station we were using. Everybody I’ve talked to who has used it has agreed with me that it works so well, you practically go out of your way to find something to desolder. XD

        1. Do they still sell those cap activated spud guns? (Rather than air pump type) Those would be the easiest starting point I’d think. Though now you’ve mentioned spud guns I wonder if the air pump type would not be more practical.

  3. I am thinking that if you are 3Dprintern’t, then maybe finding an old, clogged up spray gun would be an option for producing vacuum from compressed, air. You’d drill out the clogged nozzle, or remove it, and restrict the gaping hole with whatever methods are expedient, connect the air in the normal place, and it would suck from the pickup tube that would normally go in the paint reservoir. Staple shut the leg of your cutoff jeans, and ziptie the other end around the nozzle and there’s your bag to catch the solder. Would likely be prone to solder clogging, as is pretty much every solder vacuum method, so keep your unbent paper clip handy for jabbing it out.

      1. Lead solder and a hand squeezable air blower, this technique is about 20 years old.

        But I’ve made smd hot tweezers using 2 soldering irons mounted together with a hinge style joint and many other things.


        1. Funny you should mention, hot tweezers have been around for about 20 years too. Got any other tricks? Wait, don’t tell me…an oval shaped piece of glass that zooms in on your work? How about a magic box that notifies you of the voltage in circuit?

    1. Where is the problem? Of course you should not eat the dust – but in that case lead would probably not be the only problem. Bigger lead particulate is heavy enough not to stay airborne for any length of time, so no problem.
      When I use a similar procedure to clean PCB holes of solder, I just blow on the heated solder hole to blow out the solder – works quite good ad the molten solder naturally flies away from me.

  4. You can buy a compressed air vacuum venturi for pretty cheap. Then you need a filter to catch the molten solder before it hits the venturi. Not sure if it is cost effective vs other options though. I am thinking that blowing the molten solder off is only going to be good for wire connections and not pcb work. If I did not have the vacuum desoldering device I would probably be going with wick for most things.

    1. Back in mid 1980’s when I was looking to buy a desoldering station to remove failed 6526 CIA chips (40 pins) from Commodore 64’s, Pace was the brand I knew. Turns out they made shop air-powered units for repair center-level operations. They were less expensive than the Pace MBT 200 I got for $450, but my basement-based shop didn’t have an air compressor. (The very next month, it would have cost me $550!)

      For those who might care, I repaired many schools’ C64’s with this failure; I attributed it to the fact that the chip’s pins went to the joystick ports on either side of the power switch, the non-humidified winter air in the schools, and that static generating carpet they all seemed to have. Walk 5 feet, touch ground, zap!

    2. You can but most commercial desoldering guns have reviews saying they clog non-stop so I was guessing I wasn’t going to design a much better system than the pros. It could happen and maybe I’ll give it a shot! I use a lot of wick too. For scrapping stuff, this has worked better though.

  5. The most ghetto, desoldering stripping for parts Ive ever done was as a student. At that stage I couldn’t afford new parts, and scavenged parts. I bought a bunch of ancient arcade game PCBs for about 1/2 USD a piece. They’re probably sought after now, but back then they were on the way to the dump. Working outside, I used a gass stove and a screwdriver to remove the DIP chips. Heat the bottom of the board with gass while running a screwdriver under the rows of chips. I used the harvested hundreds of chips for years in hobby projects. The PCB sure smoked and stank, don’t do this indoors.

    1. Fifty years ago I coukd get “computer boards” for a dollar, some of my first parts. I recall cutting the boards up to get the parts. Much later I wondered if they were boards for driving Nixie tubes, something about them made it a possibility.

    2. I once used a tall lamp with a 300 watt halogen bulb (the long cylinder style) to remove an ISA connector from an old motherboard. It discolored the board as it started to overheat, but the socket came out okay.

  6. A long time ago, before I have enough money to buy a dessoldering tool, I used a pen tube to blow solder away. It works pretty well, you only have to take care of the spreaded solder, which is no big deal if you consider the strength of your lungs.
    Years later, the same trick helped me to service a power supply on the field.

  7. A few times when I was young, really PO’d and didn’t feel like finding and firing up the desoldering iron I would heat with the iron and use a can of compressed air to blow the molten solder out. Man I used to do some really stupid stuff, it’s amazing I still have all appendages, both eyes and ears lol.

  8. Been there, done that but differently. When I have pile of circuit bards I want to strip the compents off oc. I put on a face shield; use a Bernzomatic torch, and to melt the solder,and an air hose tp slow the solder away. Before I had compressed air in the shop I’d melt the solder, grab the board with pliers and fling the solder to the floor. I’m used to arc welding, or using a cutting torch care armed, in time one gets used to the sting of small bits, of molten metal.

      1. I use a version of this trick all the time. Hemostat clamp clipped onto the part, PCB in one hand, iron in the other. Blob on tons of solder and keep it all hot. Eventually the part wiggles and falls out.

        I’ve also done this with the hemostat in a vise, but you have to pull super gently or else you can rip out traces. (Or so I’ve heard.)

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