Soldering copper tubing

[AccApp]

I've seen so many leaking compression fittings I would never trust them for anything but exposed joints or stuff 3/8" or smaller.

[Keinokuorma]

It says in the instructions to leave the joints to easily accessible places, and the clerk should tell the customer this too when buying them... they may be prone to leak, especially on soft copper, but on hard copper I have so far had fully satisfactory results. Mostly I don't do anything thicker than 12mm, if it's thicker I prefer suggesting that the customer has a real plumber do the job. Just about anyone is allowed to do plumbing, but when it comes to insurance stuff, a certificate of competitiveness will be of help.

[JDenyer232]

Another thought is that you are getting the joint to hot and burning the flux. I usually apply heat for ten seconds at a time and test the temp with the solder. If you over heat the joint to much then the flux burns off, and the now unprotected copper oxidizes, then the solder will just ball up and roll off. Many years ago when I first learned to solder I would get the joint nice and hot and had the same problem, plumber told me I was applying too much heat, I didn't believe him, but after getting frustrated I tried it his way, and ya know what it worked! Haven't had a problem soldering since then. What I also do is heat the male end and let the heat get carried to the joint, then heat the fitting a little and voila it sucks the solder right in. Hope this helps ya out:)

[Brew Man]

Hey,

i know this is a old post but so am i. i was lead to believe that you could solder  copper tubing for water pipes,but had to braze in order to fit copper tubing for high pressure refrigerants. the difference is in the amount of heat one uses. i also have a degree in welding technology,so this suject got my interest.

[Keinokuorma]

I have soldered copper tube with tin/lead alloys, 350 centigrades and a plain propane torch is enough... solder iron can't deliver heat effectively enough. Tin/lead holds fine in automotive tubing, but you must not use it on a drinking water system! You must use an approved lead free brazing material for that.

[jehiatt]

Greetings: I went along as the helper to replace a stolen home AC condenser. The propane torch my son used took a long while to desolder the cut pipe from an elbow to which we would solder in the new condenser's 3/4 copper pipe.  That joint must have been brazed with silpox.

The new connection flowed well using Home Depots soldering kit but would not seal. After several soldering attempts and still leaking it was determined that the elbow was a plumbing copper part not a refrigeration copper part and the elbow was removed and replaced with a refrigeration 3/4 coupling that did seal ok. Maybe there is a silly millimeter or so difference.

We were out in east Jesus. I didn't bring my torches and silpox - assuming my son had the right equipment.

The Ac is still working. I don't trust that low temp solder.

What I am saying is water pipe fittings may not fit refrideration lines and solder may not seal them. Silpox can do it

Did you have a mix of fittings on this soldering problem?

 Anybody know if copper water lines are different OD than refridgeration lines? i never installed any water pipes.

[mpowell_sr_]

I may be wrong, but it appears that you may be attempting to use brazing tecniques (SP) using a soft solder product. If you are working on plumbing lines, your product is correct, but you are using way too much heat. Try a feathered flame, (your clean pipes and flux were absolutely correct) put the solder (soft, tin-antimony solder from Home Depot) on the top of the joint as you heat it (gently) from the bottom, and you win.

 

If you are doing refrigeration work, your flame was correct but your product was wrong. A neutral (that means when you increase the oxygen, the outer feather just meets the hot dark blue flame) or, I prefer,  a slightly carborizing flame, (a SMALL bit of feather flame) is best, and a 5% or 15% silver solder is required. I have never found this product at Home Depot. It generally requires that you work it around the joint, rather than just sweat it as in soft soldering, but when it looks good it usually is good.