Little Trick for Desoldering Through Hole Components




Introduction: Little Trick for Desoldering Through Hole Components

About: Maker of all trades ... or at least many :) Interested in electronics including programming, woodworking, how to grow edible plants in cold climate of my homeland, building clever dwelling houses from mostly...

Have you ever felt frustrated trying to desolder a component from a board, wishing you had one more hand?

This trick can help you with some of the components. Specifically through hole components that are mounted with a little clearance below them. By little clearance I mean at least enough room to put a paperclip wire through. And they also should not have their legs remarkably bent on the other side of the board - this method does not work if you need to use force for bending them back. This worked nice for transistors, vertically mounted resistors and diodes and some capacitors depending on their exact mounting position.

Step 1: How to and Video

(Link to the video in case the embed is not working: )

You need: rubberband and paperclip or semi-hard wire.
Straighten the outer loop of the paperclip and make a smaller hook in the end. Put the rubberband through the smaller loop. Find some way to attach the rubberband's other end to your desk. Put the wire hook under the component you want to remove. Hold the board so that the rubberband exerts a little pulling force on the component. Heat the solder joints and the component will be pulled out as soon as it gets free. The component is very likely to go flying. So be prepared to search for it all over the place. But after a little practice you will learn to pull just reasonably strong not too much and lower the chances of long distance flights.

Step 2: Clumsy Drawing and Disclaimer

Here is also a clumsy drawing of the setup.

It's so simple that I don't 100% except to be the first one to come up with the idea. But I couldn't find a mention of this kind of technique.



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87 Discussions

Very nice idea. I would refine it with fred3655's idea of a clip instead of the hook, perhaps a crocodile clip? Then it won't fly away and wait for when you want to unclip it. Of course one can marry your and fred's ideas and modify a pair of helping hands?

1 reply

A further refinement would be to determine how much stretch the rubber band needs, the feed it through a plastic tube the length of the band unstretched and attach the paper clip to it. That way the items don't fly all over the place.

I salvage a lot from boards, far more than I'll ever use but with me it's more an obsession rather than need, this little trick is going to be very helpful. The other method I favor is heating the component's pad and giving the solder a blast of compressed air to move it away from the pad, messy but quite effective, especially on multi- lead components plus the instant chill minimises overheating potential.

17 replies

If you're salvaging parts and you're using an iron to do it then you're salvaging parts wrong too. Salvage is not rework. So the same techniques do not apply. When I got 2 minicomputers to scrap for parts I had to rethink my game plan myself. I spent over $150 dollars to buy a device called a solder pot. I can put a board over it, and instantly pull up any part I want. 64 lead DIP? No problem! I can pop one of those up about as fast as I can get the board over the pot where it is. You'd be fooling with that all night long using a soldering iron. It'd be beat by the time you were done playing around with it then too.

Good luck trying to blow solder out of a well made through hole plated circuit board too. It's not gonna happen. With rework you're trying to save the board, with salvage you're trying to save parts. So different techniques work best in the different situations. With salvage you don't care what happens to the board, with rework you don't care what happens to the part. These concerns dictate totally different plans of attack too.

I try and limit myself to the ways and means other people have Fred, a kid in
Chattisgarh India or Addis Ababa, Ethiopia may only have a soldering
iron and pliers as his toolkit while trying to learn electronics, and
little else. The simple tricks like the author posted increases the
chances of a succesful part recovery at no cost, and is easy to
employ. The compressed air technique I mentioned was posted up on
Youtube by a Russian lad, and again is quite effective for what
little he had in the way of resources. $150 for a solder pot =9,228
Rupees, where the mature skilled worker makes only 240 Rupees a day is a distant dream, most surely never to be realized. Their only way
out is through self- education, which is why I posted my small
contribution to the subject, but I do understand your methodology

Yeah you could get a piece of sheet metal, dish it out, throw some lead on it, and put it over a barbeque too. I saw a video on Youtube of a fellow in China doing exactly that. If I'd seen that before I bought my solder pot I might have gone a different route myself. But I bought my solder pot before the Internet really got going. So I went the way I did. Fact is molten bath is the way to fly. Get in on it however you can.

I also saw a guy using a flat clothes iron to affix SMD's to his p.c.
board, I figured maybe that could work in reverse and mimic a solder pot
so I got an old electric griddle from a thrift store, and sifted some
sand and tried using it as a "hot box", Unfortunately it wouldn't get
hot enough and I didn't want to mess with the thermostat, but one of
these days... I initially used the same technique with a camp stove, sand, and a tray and it did work, freeing up the components, but it was too difficult to regulate the heat to attain detachment but not immolation of the components, so I do think the idea is workable with the right combination of elements.

SMD is not slang, it is an acronym. An acronym that is completely recognized by industry too. SMT is also a valid acronym, though less used. SMT stands for Surface Mount Technology.

It does destroy the PCB but using a propane torch and rapping the hot board on a dishpan usually dislodges most of the components. Do this outside as the smell and smoke is really bad.

I did try the torch method, it was difficult for me to get the timing and movements coordinated without suffering too much component loss, and yes, the board is trashed. The most effective methodology would be one that acts like a solder pot, allowing ample time to pluck components without damage, but be of little or no cost- I gotta revisit the sand hot box again someday, I'm pretty sure it'll work.

Forget about dry heat. You want the wetting action of liquid solder to desolder with. Sand is not going to get you that. Liquifying solder efficiently is about more than just heat. Get some heavy gauge sheet metal and bash it into a shallow dish. Then throw some lead on that, and get some heat going under it. Once you got a puddle of molten solder going you take a board held in pliers and just dip it into the top of the puddle, so the bottom of the board is in the puddle. Then quick as you can pick out parts. In a fraction of a second things are loose.

What I do is dip, pull some parts, then set the board aside, so it doesn't get too hot. I generally tend to strip about 5, or so boards at the same time. I can do 5 large, heavily populated boards in about 45 minutes. When I'm done I got a pile of parts then too.

One of the biggest problems today is just finding lead. When I got going I could still get bars at a plumbing supply house. They don't use real lead at all anymore with plumbing. I hear they still use real solder for roofing. Sometimes I find old wheel weights on the side of the road. New wheel weights aren't lead either. I've even melted down old battery plates to get the lead out of them. That's a bit iffy, so I can't recommend it really.

You only need a puddle about as deep as the clipped leads are long on a board. Just so you can get the bottom of the board into the soup. Once you've tried this you'll know I'm right. You'll be like, this is magic!

While torches work they do tend to fry boards really badly, and there is no wetting action going on, so breaking a sweat on the solder with a torch is more difficult too. I generally don't recommend people try to use a torch in salvage, as it is just that much less effective compared to liquid solder.

Plus as BeachsideHank points out below controlling a torch can be tricky.

I don't even waste my time trying to salvage SMD. The industry went to that technology partly to discourage people from getting any use out of their manufactured products beyond obsolescence. They'd rather you just gave them more money.

pf2, okay, I see what you are saying. Great idea.

That's it. Connectors are hard. They're easy to melt. He needs bent pliers. Straight ones suck for pulling. With straight pliers your hand ends up on the board. I even find a pick handy for pulling parts. I'll take a picture of my parts pulling pick I use. You're better off standing up doing it too. I wear a leather apron. Molten solder is no joke! I should add that I also hold the board with a pair of Channellock pliers. The gooseneck is better, and it keeps me over the molten solder too.

Anything besides wet pulling is a waste of time. Usually a waste of good parts too. Wet pulling is the safest as far as overheating is concerned. You're just screwing around with stuff for a much shorter period of time. It is heat over time that cooks parts. So speed is essential in the process. Plus you don't want to be spending a dollar's worth of your time harvesting a part worth a nickel. If you're good you can pull about 2 parts a second.

At that rate you're getting around $360 worth of parts an hour. Which is worth doing. I test, and use ICs I've pulled, and they're all good. So I must be doing something right. I've pulled ICs worth $50 a piece. Though when I was pulling them I didn't know. Go price what vintage JRC4558s cost. I found a board with 3 of them on it. You can see one here

It is doing what it was born to do in that project.


You have me curious.

What's the make of this soldering pot your talking about?

Seems that your $150 investment in a large solder-pot sort of negates the economy of salvaging parts.