De-soldering Guns

[No.1 Labrat]

Hi all.

It seems every circuit board nowadays has plated through holes. Trying to de-solder them is a real battle, especially now that lead free solder ? is used.

I have seen people using mains powered vacuum de-soldering irons, on YouTube.
They seem to work well, and none of the users complained about them.

Searching e-bay I can only find a model S-993A. Is this the one to buy ? Not cheap. What do you use, recommend?

By the way, after years of using all sorts of soldering irons, I have gone back to the trusty Weller WTCP 50. Finally an iron that does not eat tips for breakfast.

Wayne.

[Welsh Anorak]

I've not been lucky with the gun on mine, but that's quite possibly a one-off.
Far cheaper is the 'heated desoldering pump' available for around £10 on eBay or CPC over here. It's like the traditional pump but with a built in element. I use one occasionally. It won't stand up to much use, of course, but is handy for removing larger items from a board, and it does leave a clean hole. Both this and the one you mention need to be kept in very clean condition as they soon clog. You need a fine piece of rigid wire to clean the nozzle.
Depends how much desoldering you're planning on doing, of course. A good quality solder wick (forget the cheap ones) is essential as well as a pump.

[HECTOR63]

Vellerman do one on Amazon that might be worth a look, but Ive done most of the major ones in the past from Full Pace stations to Metcal etc and they all clog like crazy and cartridge filters and vacuum tubes etc also tips are all maintenance issues on a regular basis! Very frustrating when you spend that kind of money! Good solder wick and decent Wellers are always good. But the best value for the money by a long shot are the Hakko not cheap but then no the cost of pace etc either! But certainly do the micro pinholes a treat but again depends on how much use and component board etc integration issues your up against. The biggest issue as you highlight aswell is the lead free solder dreadful stuff and very tricky to work with, that's why most manufactures these days either offer complete board replacements or price the spares to reduce the products to scrap values.

[Radio Wrangler]

The best de-solderer I've ever used was a system that provided serious suction powered by a compressed air line and an 'exhauster' valve. The exhauster was made by Aga I'm not sure where the filters came from, but the hand pieces took standard EDSYN solder sucker nozzles.

It really sucked plated through holes dry, but boy did the boards have to be good quality to keep the pads on.

I think you run into a trade off between sucking the solder and sucking the pad.

I sometimes add more solder because there seems to be a sweet spot in terms of quantity, any less and there isn't heat transfer and isn't momentum. Adding leaded solder will help dissolve the lead-free stuff and make it easier to remove.

David

[HECTOR63]

I sometimes add more solder because there seems to be a sweet spot in terms of quantity, any less and there isn't heat transfer and isn't momentum. Adding leaded solder will help dissolve the lead-free stuff and make it easier to remove.

Yes I would second that and does work very well indeed, very good point regarding the pads aswell. Just because someone has all the right gear etc doesn't make the risk assessment any easier, its just hopefully finding something that works for you but I would spend some time on a scrap board with different parts to challenge removals and see how you get on.

[cmjones01]

I bought a slightly dog-eared Hakko 474 desoldering station with 809 gun off eBay a few years ago. Parts are readily available because it seems to be a pretty industry-standard unit, so getting hold of new filters and the right proddling tools to keep it clean was easy. I've used it lots for desoldering DIP chips off 1980s arcade game PCBs, some of which are pretty fragile, and it's worked delightfully well and saved hours and hours of time. It pays to check all the parts which could get full or blocked regularly, though.

Chris

[HECTOR63]

This is an example of what most service centres use to use years ago fetching about £600 plus these days but at the time were the best part of £2K but with skill they were superb and could undo virtually anything as well as rework

[Terry_VK5TM]

Just don't buy something that works like the old spring loaded vacuum desolder things - they have a nasty habit of jumping and ripping pads off.

The S-993A works OK and you can buy at a good price if you search around.

You only need to desolder a few parts to appreciate the convenience.

[SiriusHardware]

I have access to two desoldering handpieces, one an old Weller which I bought on the way out of a job where we had all just been made redundant - I think I paid £60 for the Weller desoldering station, my Fluke 83 DMM and a three-section bench PSU. At work I use a Metcal.

Both of these units, in common with all other electrically pump assisted desoldering irons or guns, are fantastic and indispensable as long as they are maintained and care is taken not to let anything get jammed in the nozzle, and not to allow old burned flux to build up and narrow the channel to such a degree that it is no longer possible to push a clearing rod through.

In short, they are extremely high maintenance, but if you can keep on top of that you will wonder how you ever got on without one.

I've had some experience of a low end Duratool model sold by RS, and on that particular model there was something badly wrong with the way the handpiece was designed because it was barely possible to get the glass waste chamber out of the gun and back in again, the 'breech' didn't open wide enough to allow the tube to come out and go back in easily. I think I even subsequently found some Youtube videos describing how to modify the handpiece to make that part work the way it should.

But when it did work, even that low end model was quite good, and vastly better than a 'passive' hand desoldering pump.

One of the things to look out for is the price and availability of tips. My Metcal at work uses tip / cartridges which are currently about £30 a go, so I'm glad I don't pay for them. For home use a model like the Duratool, which uses tips which are simple conical pieces of metal, are much to be preferred.

[ortek_service]

Originally Posted by HECTOR63

I sometimes add more solder because there seems to be a sweet spot in terms of quantity, any less and there isn't heat transfer and isn't momentum. Adding leaded solder will help dissolve the lead-free stuff and make it easier to remove.

Yes I would second that and does work very well indeed, very good point regarding the pads aswell. Just because someone has all the right gear etc doesn't make the risk assessment any easier, its just hopefully finding something that works for you but I would spend some time on a scrap board with different parts to challenge removals and see how you get on.

Adding fresh solder also adds more flux, and is what I always found was needed when I only hand a standard hand-held Desolder pump (Although at least the 'Green' RS one, I 've found to work the best with good suction and little recoil - compared to the first one I got from Tandy's, that the spring was was so powerful the pump would easily jump out of your hand when triggered, so very easy to damage PCB) and I didn't have any liquid flux.

These days, I often use a flux pen / bottle with needle nozzle, but have also used it in a spray can - Although you do apparently have to use the right type for either leaded or lead-free solder.
Lead-free solder often doesn't like mixing very well with leaded solder, as you often have to ensure there's no lead content on everything inc. the component legs, for lead-free solder to work properly. So need to remove it all, if resoldering with leaded solder, that doesn't mind if component has lead or not.

I've tried the odd (new) Weller desoldering tool, and also recently a Pace one. But I was rather disappointed, that I couldn't get them to work as well as my favourite 'RS' normal desolder pump. These do need a vaccum pump base unit, so are normally around £1k new. I never got chance the chance to try a Metcal one, that compressed air supply to create a vacuum effect.

For desoldering multiple DIL IC's, like RAM's, I now tend to use a variable temperature & airflow Heat gun. It seems to be the least risky way of damaging tracks, being able to heat all joints at once whilst using a chip-puller pliers tool on the other side, but you do need to keep it moving and have setting right, to not causes PCB to start to go a bit brown if kept there to long. Although then need pump / lots of wick, to clear all the PCB's through-plated holes (but much easier with no IC's pins in there).

The mentioned Heated desolder pumps are something I haven't seen yet, so might be tempted to see what one's like.

[Beardyman]

Having used both the Metcal & Hakko systems in the past I think Hakko has a slight edge, Metcal parts (although good quality) tend to be a little overpriced. Anyway, as others have said, sometimes adding a little extra solder can often help in getting heat into the joint quickly, that's the trick really. A liquid flux can help too. I use what some would call an oversized bit on my Metcal just to get as much heat in the joint as quickly as possible, hold it there for 3-5 seconds (seems an eternity!) then an ordinary hand pump applied will usually clear the joint. After that use a good quality solder wick, dipping it in liquid flux can help here as well.

[Wendymott]

When I worked for NEI in Bradford, "TV Assy".. we often needed desoldering tools, we bought the Weller... it had a Quartz glass receiver at the head of the tip, these seemed to work quite well until the tip hole bunged up.... they had to be kept clean, otherwise the dried flux powder clogged them up. Occasionally the glass tubed broke and were fairly expensive, each iron needed a vacuum pump... generally we only had one station. Today I use a heat gun with a small tube tip. No good for teensy SMD parts..I only use for stripping modules these days.

[ortek_service]

Originally Posted by HECTOR63

This is an example of what most service centres use to use years ago fetching about £600 plus these days but at the time were the best part of £2K but with skill they were superb and could undo virtually anything as well as rework

That one looked liked it was just a hot-air reflow system, with under-board heated bed (And I've used a similar Weller system that had interchangeable nozzles inc. QFP ones, that also had vacuum pick to lift the IC off the board).

So could it also do desoldering of through hole parts, by extracting the solder from these, or did it just use hot air to try to heat all the joints simultaneously, to pull a DIL etc. device out?

[HECTOR63]

With this unit it was designed for precision lifting of Ics and all the really tough ones aswell as some manufacture's use to use a light bonding in manufacturing to hold ics in place when being flow soldered in production, Needless to say if you were not aware on that at the time then you so had a serious issue on your hands, that's why when the underboard heaters became on this type of platform they made life so much easier. I can actually remember whether these supported through hole DE soldering but they may have had a pack that could adapt a through hole in a vertical position(bit like a pillar drill) and allow that to perform extremely accurate placement of nozzle over hole etc and probably be vacuumed pumped either from internal source or air line as necessary. But all in all a very credible tool if you spend some time with this type of technology of which most workshops were inundated with in the latter years of 2010 onward. But again Hakko have the best supported various option from Irons, heated tweezers all the way through to reliable desolder guns. Matter of finding the right solutions for you, but they really have made there name in this Genre.

[chriswood1900]

I use either the the heated pump mentioned above for small quantities at around £12 or if I have lot to do I use the Duratool D000672 from CPC with good results and have been able to get spare elements, tips etc for it from CPC.
https://cpc.farnell.com/duratool/d00...ug/dp/SD01384?

[SiriusHardware]

That looks a lot like the Duratool one I've used a couple of times, although it was black rather than grey. The gun in particular looks very similar. What's it like getting the glass tube in and out of the gun on that one? That was the only problem I had, when the glass tube was 'released' the two surfaces which normally grip it didn't move apart far enough to allow the tube to come out freely, so trying to get it out to empty it was potentially quite damaging for the end seals.

[chriswood1900]

Getting the tube in and out is fiddly but can be done, that is about the only thing I don't like about it.

[SiriusHardware]

Interestingly this has (I find) already been discussed in this now closed thread here. In the first post the OP gives quite a detailed description of how to modify it so that the sliding section moves far enough to allow easy removal of the tube.

https://www.vintage-radio.net/forum/...d.php?t=163807

If that modification (or something giving the same result) was done, I can't think of anything else about those Duratool units that I could really complain about.

[tritone]

As already mentioned,

1. Definitely re-flow the joint/s with good a quality leaded solder.

2. Apply plenty of proper electronic rosin to Both sides of the component/s legs and pads and desolder quickly.
If possible, keep your circuitboard verticaly to your horizontal suction direction

3. When you have the component removed; If there is still a blocked up through hole pad, use a wooden cocktail stick/tooth pick dosed with rosin and your soldering iron to clean out the through hole with care.

4. Good quality rosin is your friend and don't be afraid to use plenty of it. Too much heat from your de-solder gun or iron is your enemy.

5. Clean up with isopropanol, an old toothbrush, earbuds, etc.

6. Oh, I forgot and this is very important; Quite a lot of manufactured circuit boards that are populated with components from the factory have the legs folded over on the rear side. Straighten those up or snip them with a pair of one sided proper snipping side cutters before you start. .

[PaulR]

I also have one of the Duratool ones. Getting the glass tube off is a fiddly business and the nozzle does tend to block. It would be no good for continued professional use but for occasional use I wouldn't be without it. It makes desoldering very much easier