Soldering drain pipe from tough angle..standard test to verify solder took?

[Lithnights]

I just soldered a 1 1/2" copper pipe to a brass fitting. I heated the fitting for a good while (longer than my typical 1/2" copper sweats) then soldered and the solder took pretty nicely all the way around.

My only issue is that I was soldering from an angle where I couldn't see the bottom of the pipe. I got down as low as I could and definitely saw the solder taking. This is the drain for my soon to be installed bathtub. See attached picture.

Is there a standard way to test this joint to make sure I don't have any leaks? I assume I could set up some contraption or dry fit my overflow assembly and run hose water through it to see if there are any pinsize leaks...?

Any other ideas? I want to make sure it's a solid fit before installing my tub and then tile over the tub. Once that's in, I'd be stuck if it had any leaks. I guess I could always get to it from below if needed but that would require ripping a hole in my 1st floor ceiling.

Thanks in advance,

 

[Cass]

Use a small mirror and flashlight.

 

[Sponsor]

 

[hj]

joint

You are going to test the drain system after you install the tub, but before you tile aren't you? If so, you will find out then if it leaks.

 

[Gary Swart]

Not saying don't test it, but in the photo, it looks pretty good and I think you'll be fine. I had a similar problem when I redid my irrigation line where it branches off of the main line. It's 1" copper 5 feet deep and I was almost standing on my head. I probably used enough solder to do 6 joints, but it didn't leak.

 

[Lithnights]

Cass, good suggestion, I had actually done exactly that and it LOOKED good. But I guess I'm afraid looks can be deceiving.

I guess I will just do hj suggest and just test the drain system after tub install but before tile...

Thanks all.

 

[hj]

test

You had better do it, because that joint is not the only place you could have a leak. Finding a leak after the tile is on is not a pleasant feeling. It ranks right up there with finding out the tile layers decided to make the tile 1 3/4" thick instead of the 3/4" originally indicated, and the shower valves, (plural) never had that much adjustment in the first place and there are no extensions. That happened today.

 

[Prashster]

Feel the bottom. If you have a beaded bump, you'll be good.
If you're gonna have a blind spot, the bottom is the best one to have. Solder will naturally flow down to the underside. so that side is usually the easiest to fill.

 

[hj]

bottom

But heat rises so if the flame was not directed at the bottom, it could be cool enough not to flow the solder.

 

[Prashster]

Heat doesn't rise. Hot air rises. Heat conducted through copper radiates up and down with equal speed. Liquified solder sucks into the joint bkz of capilary action - a tiny air gap acts like a vaccuum in the presence of heat or even the most minute pressure differential. Once it's sucked into the joint, though, it follows gravity.

If you heated only the very top apex of the fitting and fed in solder only at the very top, it's possible that it'd cool b4 flowing to the bottom. But, if you made even the feeblest attempt to evenly heat the fitting, and to feed the solder from the side or as low as possible, than the bottom of the pipe will certainly have heated thoroughly enough to let gravity do its thing on the liquified solder, and you'd get even coverage.

If the TOP was the area in question, I'd argue differently.