Desoldering how to?

[Grizzly bearParticipant @grizzlybear]

Hi Ian,

Congratulations, very satisfying I'm sure.

My interest has been hobby oriented, I too enjoyed the electronic magazines, especially 'Television' the follow-on from Practical Television.

Now, the www. is so useful for gathering information.

Regards, Bear..

[John HaineParticipant @johnhaine32865]

Possibly a bit late, but I used to have a very nice tool from Maplin which was a combined iron and sucker. Until the element went it worked very well, but when it did go Maplin had gone too and I couldn't get a spare (even had they stocked 'em).

[noel shelleyParticipant @noelshelley55608]

Sorry to come in late, Before I'm shot down in flames, I know it can be messy But I have used an airline blow gun with good results. The blow was far more powerful than the suck. Noel

[Kiwi BlokeParticipant @kiwibloke62605]

Interesting thread…

In retrospect, I realise that I have found de-soldering modern equipment to be more of a challenge than it used to be – even allowing for component density, failing eyes, etc. The comments above to first add solder was a lightbulb moment, I think. I customarily use a well-loaded iron to de-solder. I thought it made things easier because it provided better thermal contact, but I bet it's a lot to do with adding lead to the new-fangled lead-free solder joint. I don't use lead-free solder, know that it doesn't flow as well as 60-40 and a repair man I know says the move to lead-free was the stupidest thing ever forced upon manufacturers. The joints are prone to failure, tin whiskers grow between tracks and components and (elderly) joints just seem to fall apart. After a dose of lead into the joint, solder suckers work pretty well.

So, the message is: add solder first, but use good old 60-40 lead-containing solder!

[Nicholas FarrParticipant @nicholasfarr14254]

Hi Andrew, it is indeed a 250W made by Solon. I also have my fathers 65W one of the same make and style, which is more practical for many jobs and also a variable temperature solder station and a 15W Antex Precision, a Weller Universal, a Black & Decker one in a similar vein to the Weller, and a 12V 17W one that can be clipped onto a battery or suitable 12V supply, plus about three of my fathers that have to be heated up with a flame. The B&D and the 12V one, along with the flame heated ones, very rarely get used now though.

Regards Nick.

[Martin KyteParticipant @martinkyte99762]

Professionally I use desoldering braid more than I do solder suckers.

Braid

Particularly on delicate tracks/components. The other usefull function for braid is to remove old solder which can get somewhat pasty making it difficult to desolder stuff. A cycle of remeval with braid and then resoldering with new solder often results in a 'fluid joint' which is more ameanable to desoldering by your preferred method.

When removing 'dead' components do cut away whatever you can with side cutters to allow pins to be removed one at a time is possible.

regards Martin

[Danny M2ZParticipant @dannym2z]

To desolder a through hole component a hollow tipped soldering iron with a vacuum pump is pretty handy.

Many years ago I attended a RAAF course for High Reliability Soldering Instructors. This was based on NASA best practices.

Imagine my amusement when some of the solder joints that the class had made were projected onto a large screen, microscope photos magnified to over 2m across and the class were invited to inspect our work and offer a critique.

This was very educational and as many of the class were working on aircraft instrumentation it was vital that our work was as perfect as humanly possible.

One thing that I did learn was that many (cheap) commercial solder suckers (especially with a Teflon tip) can generate a large ESD (Electrostatic Discharge) pulse if they have a plastic body so nowadays look for an ESD safe solder sucker if that's what you use

As for soldering braid, it;s useful to remove solder from the base of a 1950's valve base and indeed I still have a few reels which are useful for repairing model aircraft fuel tanks but for printed circuit boards it's only good for lifting tracks.

After I left the old job I managed to find a decent soldering station at a mil surplus auction along with lots of tips.

I paid a lot (lot) less than the original price so pretty happy.

* Danny M *

[Martin KyteParticipant @martinkyte99762]

"As for soldering braid, it;s useful to remove solder from the base of a 1950's valve base and indeed I still have a few reels which are useful for repairing model aircraft fuel tanks but for printed circuit boards it's only good for lifting tracks."

The avoidance of lifting tracks is the precise reason I use it.

regards Martin

[Ian ParkinParticipant @ianparkin39383]

I saw a desolating iron on amazon

and it works a treat on some sample boards

it leaves fully open holes components come straight out and new ones go easily back in

And only £13

i wish I’d had it yesterday desoldering 20 leds

[SillyOldDufferModerator @sillyoldduffer]

Posted by Ian Parkin on 10/03/2020 18:32:06:

I saw a desolating iron on amazon…

A 'Desolating Iron' – surely that's a Freudian slip! It describes my de-soldering experiences to a 'T'.

I shall order one – really good idea if it works. Can't go wrong at that price, famous last words!

Dave

[SteviegtrParticipant @steviegtr]

That will be a lot better than my solder sucker. Same principal But I have vac pump in one hand & the iron in the other. A pain to use. Looks good.

Steve.

[Andrew TinsleyParticipant @andrewtinsley63637]

Having a problem sorting out which desoldering iron on Amazon is being recommended! Can anyone give me a link please?

Thanks,

Andrew.

[SillyOldDufferModerator @sillyoldduffer]

Andrew – This is the one Ian Parkin mentioned.

[Neil WyattModerator @neilwyatt]

Does anyone else use a rework station/hot air gun?

They really do make desoldering a pleasure, especially combined with a quality solder sucker.

Neil

[Andrew TinsleyParticipant @andrewtinsley63637]

Thanks Dave,

Much appreciated.

Andrew.

[Joseph Noci 1Participant @josephnoci1]

I use solder wick extensively – once you have the feel, it works very well. A HOT iron, with sufficient thermal mass, and quick work..

Also use a solder sucker for things like the 1 or 2 mm square legs of big transistors on power amps – else cut the legs and remove easily one by one.

For finer stuff I use these tools ;

A board pre-heater-

Hot Air pencil ( goes to 450deg C)

From 6mm to 1.5mm orifice.

And most useful of all for SMD work, and for DIP IC removal. Tips also available for QFN, etc..

Metcal Tweezers, up to 40watts /tip

Joe

[Robert Atkinson 2Participant @robertatkinson2]

As well as adding solder to the joint (as suggested by Andrew) it is also very helpful to add flux. (Rosin based not Bakers fluid!). I now use the liquid flux sold for SMD rework but have in the past just dissolved rosin (for violin bows) in alcohol (IPA or ethyl are fine).

Robert G8RPI.

[Martin KyteParticipant @martinkyte99762]

If you are modifying commercial boards they are likely to be lead free solder which doesn't seem to run quite as readily as full fat 60/40 especially the second time around when it has been alloyed a little with the copper etc. Adding new solder gets you around this as well as bulking up the joint which allows the heat to flow more readily.

regards Martin.

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