Tag terminal desoldering technique/s ?

Be very careful when working on tube sockets, expecially 7 and 9 pin miniatures. The terminals can and do break off, then you have a real problem.

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I use a solder-sucker. It gets down into the blob and pretty much gets all of it. If the solder is stubborn and does not stay liquid enough, I will 'refresh' it with a bit of new solder first.

Such tools may be had at any electronics shop, either as rubber-bulb devices, cheap and easy, or as a spring-loaded device that is a bit more expensive and awkward to use but can be much more efficient.

There are specialized de-soldering irons with such devices pre- mounted.

There are also fancy vacuum-aided devices for which I have never (yet) had the need, but I hear-tell they are super at what they do.

Peter Wieck Melrose Park, PA

One of these things:

The little rubber bulb squeezy things are inadequate to the amount of solder to be removed from the terminals.

For the most part, the vacuum pump desoldering irons are great for printed circuit board work, but are also inadequate for vintage equipment desoldering. The primary problem being the small size of reservoir requires emptying about every 5-6 "normal vintage radio joint"

In addition to the probe technique, I will heat up the terminal, then wiggle the one lead in particular as it cools off. This gives me a nice "cold solder joint" and makes it obvious as to which lead is the one that needs to be gone. I'll use a sharp pair of cutters to clip the specific loop around the terminal. When reheated again, the lead usually pulls straight out and the wrapped part falls off.

Jeff

I suppose a "me-too" post isn't in order, but this is one... I've used the spring-loaded devices and they work quite well on tag strips. I've not tried the rubber-bulb ones, would think they'd be a bit short on suction for some applications.

We used to have one of these at work. It was OK for circuit board work but even there, I think the spring-loaded suction device worked better. I don't think you'd have much luck with the powered-vacuum unit on a tag strip.

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Generally, one should not need the 'heat sinks' as the insulation should be able to stand the heat of soldering the terminal [tag] in the first place. Use of the heat sinks can often render effective heating of the joint impossible because they draw off too much heat from the joint! It is very important to have a soldering iron with an adequate reservoir of heat to be able to heat the tag and connected wires very quickly, but at the same time not too hot. I use a 7/32" chisel tip at 700 degrees. I apply a small dab of fresh solder to make good thermal contact and the instant the solder on the tag melts, use a spring type solder sucker to clear the bulk of the solder from the joint and, as it cools, wiggle the wire of interest to form the cold joint. A probe, fine cutters and long nose pliers will usually remove the wire of interest, even if it means unwinding several other to access it. The old solders are usually so soft that it is often possible to simply tear the wires out of the joint cold once the bulk of the solder is removed. Always try and clear the joint in a single application of heat and solder sucker since repeated or prolonged heating will quickly do serious damage to the tag insulator and erode the base metals of the tag and connected wires.

Neil S.

Jeffrey D Angus wrote in news: snipped-for-privacy@news1.newsguy.com:

I favor my Edsyn SoldaPult;it sucks the solder off terminals and then I can unwrap the leads. sometimes I use a dental "excavator" to lift the lead,it has a chisel tip.

--
Jim Yanik
jyanik
at
kua.net

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On vintage gear I use a spring loaded solder sucker plus a sharp aluminum (aluminium) probe (like the OP's needle probe - solder won't stick to it.) Usefully, one end has a 1 mm slot about 3 mm deep with sharp points on each side. This allows a controlled rotational leverage to unhook those "mechanically anchored" wires that are such a pain to get off. As other posters have said, the addition of a little new solder can give a better heat transfer from the "iron" and assist flow in the old joint. Cheers, Roger

I heat the joint and push a sharp dental type tool into the mass, usually I can find a way to push it all the way through. Let the solder set, pull out the tool, insert the wire. Ken

Those really suck.

The rubber also seems to crack and crumble after a few years. I had several in my tool/junk box, all of which are now useless.

They work quite well. I have a Pace desoldering station and a much cheaper Chinese clone at home. I still use the solder pump, but for unsoldering a board full of components, nothing beats the desoldering machine. Highly recommended, but not cheap. Plan on buying some spare tips and a tip cleaner as they do clog if used often.

It's not the reservoir that fills. It's the cotton plug inside the glass cylinder that fills. However, it's not important as the tip will clog long before the reservoir fills with dross.

My solution for large parts is a bit more disgusting. I don't care about saving the solder or where it lands. So, I use an air compressor to *BLOW* the solder off the terminals instead of sucking. A piece of box cardboard serves as a sacrificial target. Safety glasses, gloves, and a long sleeve shirt are quite useful. Get the joint hot, and hit it with 120 psi of compressed air and it's instantly clean. The dross comes off easily from everything except plastic and rubber insulated wire, which the dross will melt.

Incidentally, the air compressor technique is also effective for deslobbering large circuit boards full of useful components. In the past, I would insert the board into a bench vice, heat up the solder side with a propane torch, pull back on the board, and let spring tension launch the components in the opposite direction. Kinda messy, but very easy and effective. However, some boards simply will not bend enough to make this method effective. In addition, the components near the bench vice usually fail to desolder themselves. So, I now use a propane torch and air compressor to do the desoldering. That works much better, creates a more concentrated mess, can be performed in any position, but does take somewhat longer.

Yeah, that also works. I get the same effect with short blast of cold air from the air compressor. Instant dross.

The other Jeff.

--
Jeff Liebermann     jeffl@cruzio.com 
150 Felker St #D    http://www.LearnByDestroying.com 
Santa Cruz CA 95060 http://802.11junk.com 
Skype: JeffLiebermann     AE6KS    831-336-2558

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On vintage gear I use a spring loaded solder sucker plus a sharp aluminum (aluminium) probe (like the OP's needle probe - solder won't stick to it.) Usefully, one end has a 1 mm slot about 3 mm deep with sharp points on each side. This allows a controlled rotational leverage to unhook those "mechanically anchored" wires that are such a pain to get off. As other posters have said, the addition of a little new solder can give a better heat transfer from the "iron" and assist flow in the old joint. Cheers, Roger

Aluminium ? I can't beleive that is strong enough. Sewing needles are stainless steel which is fine with lead/tin solder but interestingly, for diagnosis purposes, lead-free solder will adhere to stainless steel, requiring more than just a fingernail to scrape it off, more likely requiring pliers of some sort.

-- Diverse Devices, Southampton, England electronic hints and repair briefs , schematics/manuals list on

I like this idea , I'll set my mind to how to get a short burst of compressed air and give it a go. At the moment thinking of a pumped-up innertube and a solenoid valve, I doubt full compressed air pressure would be required for molten solder. No workshop compressed airline unfortunately.

--
Diverse Devices, Southampton, England 
electronic hints and repair briefs , schematics/manuals list on 
http://home.graffiti.net/diverse:graffiti.net/

"N_Cook" wrote in news:g4gs4i$vuc$ snipped-for-privacy@registered.motzarella.org:

I suppose you could look into one of those "portable air" systems out now,that use paintball gun tanks and a regulator to supply air/nitrogen/CO2 to air-powered tools,they hang off your belt.Tanks of varying sizes are available,too.Refill them wherever paintball refills are offered.

there are inexpensive air accessory kits available that include a coiled hose,nozzle,quik-connects,tire inflators.

--
Jim Yanik
jyanik
at
kua.net

I just tap or snap the terminal when the solder is melted and it just flies off, then I can pull the wire out. Sometimes you have to remelt and resnap to get the hole clear for another wire.

--
Claude Hopper  ? 3     :)  7/8

Yes, gravity is your friend. But it's kind of hard to do when the terminal in question is parts of a large chassis.

Jeff

I have 2 of these (office and home):

It's fairly minimal, but works well enough if you give it time to build up the pressure. Spraying hot solder all over the office is generally a bad idea, so I do it outside. I also use it to clean out the dirt and dust from various electronic devices. It's small and portable, so carrying it outside is easy.

I use a standard "safety" blow gun with a conical tip. I suspect I could do better with a customized blow gun tip, such as using a baskeball filler adapter with the end ground off, but haven't bothered to try.

These were on sale last Christmas for $75 so I bought two.

--
# Jeff Liebermann 150 Felker St #D Santa Cruz CA 95060
# 831-336-2558            jeffl@comix.santa-cruz.ca.us
# http://802.11junk.com               jeffl@cruzio.com
# http://www.LearnByDestroying.com               AE6KS

Keep some sacrificial tube around and put them in the socket before desoldering. I have cracked too many empty sockets. Especially the Philco

40-*** grey locktail socket on the second tube in the line up.

I try to splice (hooks) in the new componants unless the under chassis is supposed to be replicate/restored.

Paul P.

Not gravity, it's inertia. Place chassis on flat table. Lift one side of the chassis. Heat the joint with a soldering iron. When hot, let the chassis drop onto the table. Inertia will cause the solder to splatter on the table.

I used to do it this way when removing parts from old TV sets that I fished out of dumpsters behind Henry Radio (in L.A.) and local TV repair shops.

The other Jeff.

--
# Jeff Liebermann 150 Felker St #D Santa Cruz CA 95060
# 831-336-2558            jeffl@comix.santa-cruz.ca.us
# http://802.11junk.com               jeffl@cruzio.com
# http://www.LearnByDestroying.com               AE6KS

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Vacuum generators are shown here

But I think you will need a fair ammount of air , not sure how it would work with an inner tube, if you have a compressor that will fill a small tank , it might work for short bursts. Phil

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That was my first thought but it's not broken yet, and it's had a few tough twists over the years! Perhaps it's an alloy. It came with my old Weller solder gun over 25 years ago, both still going strong. I only use tin/lead solder so the stainless sewing needle is a good idea (but you don't get that "slot twist".) I'll ask my wife for one, she's from Southsea (not far from you), so pretty resourceful! Cheers, Roger (near Toronto, Canada)