can a 1/2" copper 90 elbow be re-soldered

[bent]

Its a minor leak I just noticed and probably only occurs only after water flows through the joint. Thought it was condensation. Under std. pressure and no flow, little if any water on tissue paper. I am just assuming its gonna drip some (more) after I run it some, given the evidence. Drying/wicking now. Some time ago, I may have aggravated a little with a tug too hard.

If there is in fact a hole/crack/passage caused by stretching open a crack at the joint and if the solder should be enough to COVER that area can the joint be reheated with a (std. old legacy technology type) propane torch. Can solder be added when its at temp? Its an older thing, thats known. There isn't any reason I couldn't drain the line, but is it possible to take this to extremes, or not be too concerned (more later).

Secondly, what about those tapes that are supposed to wrap around and seal. The drip is likely almost something to turn away from, change the dressing every once and a while. Can these tape products, or I've even seen a spray can, work for a little problem like this. Its really a bit of an pain, the location to just fix it with another elbow spliced in. I have one tape called "Magic Wrap" by Glasgow mfrng, London Canada. Black rubber/plastic electrical tape sized roll 1" x 16'. Pkg says "forms a solid rubber wrap", shows a brass garden faucet outdoors being wrapped, "stretches to 3x its length", "water tight and air tight to 100psi", "strong, long, all temp, conforms". I have no clue of the pressure involved. It does not look like a fiber tape, but can't ell cause its got backing on it. Don't know if I need could another type either.

ah, here's the one I have:

[Glenn]

Draining the line completely is the only way. Even a drop left close enough to make steam and it will 'not' solder.

You can always pick up a 90º - 5/8" compression fitting to take the place of the sweated elbow.

[hawgeye]

snip the magic band-aid idea.

You'll have to drain the line and make sure all the water is away from the joint or you'll be heating up the joint all day. Your best bet is to undo the joint and redo it using a new elbow. Trying to heat up the joint and adding solder could ruin both solder joints. Save yourself some grief and do it right.

[bent]

"Glenn" wrote

you haven't actually stated if its a bad idea to try a re-solder. If it works it works, and if it doesn't I can try something else, yes, no?

I'm going to check into this

got a tight job, I need more info

[CWatters]

In my limited experience....

Bad joints are usually caused by not cleaning the pipe sufficiently (eg the oxide wasn't removed with wire wool). Sometimes the joint just wasn't evenly heated and the solder didn't flow around it. Frequently reheating the joint and twisting the pipe or otherwise disturbing the joint slightly is enough to get the solder to flow around. More solder can be added while the joint is hot if necessary. If the pipe wasn't cleaned properly before soldering then best to open up the joint and clean the pipe end. You can sometimes re-use the fitting but it can be hard to get it back on cold. Sometimes easier just to use a new one.

[Bill]

I have re-used copper fittings many times. Like other posts, if the pipe is not cleaned good, it will leak, no matter how much flux or solder is used. I have seen what appeared to be a line, almost a score in the pipe. You can really see it after it is sanded real good. Make sure you use an emory type fine grit sandpaper (black)If you see a line, you need to replace the pipe. Don't forget to clean the inside of the 90 degree fitting. Good luck.