Desoldering *usable* plumbing fittings

Awl--

For 1/2" to 1 1/4" copper pipe fittings.

Possible to desolder *and* be able to re-use them?? Worth the trouble for the various fittings, T's, unions, etc? 1 1/4 unions are expensive!

Any special techniques beyond heating/wiping, heating/wiping? Wipe w/ cloth, steel wool? With, w/o flux? I think I've done, mebbe once, and it was a pita!

Btw, I found, at Home Despot, something called Tinning Flux, which lightly tins the surfaces `*before* you actually add solder. I think this is pretty neat. Any opinions? I would imagine it cleans as well as non-tinning flux, but I haven't compared.

Thanks! ---------------------------- Mr. P.V.'d formerly Droll Troll

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Proctologically Violated wrote:

unions

w/

lightly

as

I've used that flux, it works well, but it's not a replacement for proper cleaning of tubing and fitting before assembly. If you've got clean surfaces, either the tinning flux or regular flux+solder will work for tinning. If you didn't have flux or solder at all and were tooling up for a one-time fixit job, I'd suggest the tinning flux.

As to your other question, unless the fittings are absolutely green or physically damaged, there's no reason they couldn't be reused. If it's recovered scrap from demolitions, just use a propane torch to heat up the joints. As you say, new copper fittings are getting pricey these days and I don't think the quality is what it was. I had to pick through the bins the last time I bought fittings to find some that didn't have defects. Only possible downside to recycling fittings besides having to look them over well is that there may be some lead solder on them, environmentally a no-no these days. Practically, there's probably not enough remaining that it would leach out, but I thought I'd just mention it.

Stan

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Kris, I remember just heating them up and wiping the exterior with steel wool, or twisting in an appropriate tube brush. It leaves the part shiny and ready to reuse. If you couldn't reuse a part, then when you had to break a joint, you would have to replace EVERYTHING.

GWE

Kris wrote:

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unions

Do you run a lathe and mill? If so, are you aware of 3 cornered scrapers? Perfect for cleaning out solder residue while the fitting is cold and easy to handle. Takes a little time, but works well. Use a file for exterior surfaces. I always brush with a wire brush made for fittings when finished, or abrasive strip cloth for exterior fittings.

Harold

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Fittings in good condition are eminently reusabe. Just pull apart and, when reusing them, clean the excess solder out with a quick heat and a slap on something to remove the excess solder so that you can fit the pieces back together. As to the "Tinning flux", it is merely a flux which you can spread easily over the copper rather than something that puts solder on the copper. There is flux that has solder chips included in it if you want to go that way with a one-step tinning solution but the flux and solder isn't cheap.

-- Why isn't there an Ozone Hole at the NORTH Pole?

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Proctologically Violated wrote:

Yes, it's possible, in fact it's quite easy and straightforward to do. If you can get any old lead solder off it's fairly sensible for DIY usage.

A professional plumber won't do it though, for several reasons - legal regulations - the fittings won't look new, and the client is paying for new fittings - the time it takes to desolder and clean them is too long, do you know what a plumber gets paid? - the supply of used fittings is unreliable, and a reused fitting is slightly less reliable than a new one - plumbers buy in large quantities, when end feed 1 1/4 unions are no longer expensive, they become quite cheap [1], - and last but not least, in the UK at least, it's illegal to use lead in plumbing solder and the old fittings will have lead solder on them.

--
Peter Fairbrother


[1] maybe 35c each, translated from UK sizes and prices, with a 40% trade
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Yes, no, maybe, and it depends. Mostly, if you heat it up, and give it a good sling, the liquid solder will fly off and give you a nice clean piece. If they are bent at all, they can be cranky. Depending on the value of the piece, and the criticality of the application you have to be the one to decide to reuse or toss. For noncritical stuff, though, they can be reused easily.

Steve

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Proctologically Violated wrote:

I've done that many times. (If you asked SWMBO she would say of me, "Can you spell c-h-e-a-p?")

On several occasions I found it extremely difficult to get the joints apart, after they were heated to well above the melting point of soft solder. Twisting a fitting while pulling on it to try and get it to come off would produce a squeek like the door hinges from "Inner Sanctum".

I asked metallurgist about that and he told me it was due to the formation of intermetallic compounds over time, which had a higher melting point than solder.

Jeff

--
Jeffry Wisnia

(W1BSV + Brass Rat '57 EE)
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Since copper will slowly dissolve in molten solder, this causes both pitting of copper soldering tips and increased melting temperature of solder which joins copper pipes. Too much heat makes it worse, as does long heating times. The best technique is to heat the joint carefully just until the solder melts, then separate the parts quickly. Don Young

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Jeff Wisnia wrote:

Yep.

There's another similar phenomenon that's quite interesting, but perhaps not directly relevant, diffusion brazing.

You braze a joint and keep it hot for an hour or do. Note that braze metal necessarily has a lower melting point than the base metal, otherwise it would ebe welding. The lower-melting metals in the braze diffuse into the base metal, and eventually the melting point of the metal where the brazed joint was is as high as the original base metal (it can actually even be higher).

And the same Cu3Sn (or Sn3Cu, I'm too drunk to remember) molecules (*shhh..) (though they are a problem in diffusion brazing - come to think of it, they are also a problem in disassembling plumbing fittings - darn those Cu3Sn molecules!) are often involved, to bring it right back on topic!

--
Peter Fairbrother

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