Sweating mystery -what did I do wrong?

I'm a newbie to sweating - so please be kind.
I'm installing cutoff valves under my vanity (a job that should have been done when the house was built). After practicing the sweating technique many times, I thought I was ready to do the project.

The configuration is simple -- (1) connect a 45 degree elbow to a fitting with threads on the end. (I will then screw in a brass fitting which I can screw the cutoff valve to) (2) connect the elbow (which now has fitting attached) to the supply line in the wall.

BTW - I had water on hand when I was working in the wall and I also worked with a fireproof fabric shield behind the fitting.

My dilema is this -- I sweat the elbow to the fitting, and everything seemed to go as it should. The joint drew in about 1" of solder, and I could see a very thin bead of solder all along the outside of the joint when I was done. When it cooled, it was solid!

With confidence, I cleaned the supply pipe as well as inside of the other side of my elbow fitting, applied flux at the outside and inside of the pipe and fitting and made the connection. I applied heat for approximately 8 seconds to one side of the fitting and applied the solder to the other - no solder pulled into the joint. I then applied heat for maybe 16 seconds -- there was no question the fitting was hot. Again the solder would not flow into the joint. I then applied applied heat for another 16 seconds or so [NOTE: I had about 4" of solder rolled off of the spool and the last 1" was bent at a 45 degree angle so that I could determine if/and how much solder was drawn into the joint.

When I was done, no noticable solder ever was drawn into the joint; and I was going to pull off the elbow and start over. HOWEVER, the joint won't budge! I asked myself, "How can a joint be rock solid with no solder going in?" I decided to try the other supply pipe in hopes that this time I would get it right. The exact same thing happened. Lots of heat, no solder was drawn into the joint; however, the joint is solid as a rock just like the first one.

BTW: I have not attached the shut off valve yet and turned on the water to test the connection because I'm afraid it might blow!

By some magic of capilary action did excess solder from the other side of the elbow get drawn to the opposide side and cause a connection?

Sorry for the long thread, however, I thought it best to provide as much detail as possible in hopes that someone could shed some light on what I did wrong.

proabably troubles

you probably soldered both and did
not know it.....

if you got water bothering you while you are doing this
work I suggest you open the outside hose bib and try to drain down the house so the water isnt around....

find a lower spot in the system to drain everything down
to or loosen the meter in the pit

if it is thehot side you might want to
drain dthe heater down a few gallons too...



heat the whole thing up pull it apart

and try again....

hopefully you are useing some tinning flux like oaty
and sand paper to clean the joints..


good luck and have fun

The thought of soldering the opposite side of the elbow without knowing it is intriguing. How can this happen, knowing that I soldered one side and let it cool down, and then attempted to solder the other side of the elbow to the supply pipe?

I was using the water soluble flux that came with the BernzOMatic torch kit. Is this flux not adequate? What's the difference in flux?

I was using the emery cloth to clean the outside pipe and a brush for the inside. I'll make sure I keep doing that.

In the event the second side of the connection got soldered without my knowing it, do you think that I should try turning on the water to see if it's secure. If I turned on the water and there were no leaks now, should I be confident that the joint would not fail in the future?

some fluxes

some of those fluxes out there I would not
touch with a ten foot pole.........

I know better than to trust them......especially some

of those shitty "water soulable fluxes"

they are no good even for the professional

I have tried all those water soluable fluxes and they

are simply no good.....and not trustworthy...


you just got the pipe hot to anneal together

ever so slightly.....its no big deal


you can go to any hadrware store and buy a small

can of GREEN oatey tinning flux for about 2 dollars ....

if comes in a green can that looks like what tobacco snuff comes in

and that would be more than enough to do the job....

Like MPM I think your flux is suspect. Home D has the Oatey flux you need. White tub with green lettering. You should see a big difference. You may be able to heat and pull apart the fittings. Then get new fittings heat and clean off the pipe and start over.

Thanks for the great advice! You've given me the confidence to pull this apart and try again. I'll hop in the car now and go over to HD now to pick it up.
BTW: I've read that you should solder both sides of an elbow at one time (rather than doing one side and waiting for it to cool and then doing the other side) What's your advice?

Just heat the whole thing at the same time and go for it.

I went to HD and got the Oakley flux and just finished up the job. I cleaned everything thoroughly, applied the flux and sweated in both connections on the elbow one right after the other. Both joint drew in the solder and I believe that I should have some leakproof connections. (At least that is what I'm hoping for).

How long should I wait before I hook up the shut off valve and turn on the water to test the joint for any leakage?

BTW: THANKS LOADS FOR ALL OF YOUR HELP!

Turn it on.

I turned on the water, and NO LEAKS!

If I were to experience a failure in the connection, when might it happen?

I am typically very optimistic, but since I'm an abolute novice at sweating a joint, I don't want to be overly sure of myself either. Thanks!

a failure in the pipes

If yo uhave problems its usually almost

immediately.....


only my workers can solder a joint and it holds for
about half a day..... its actually a timed release leak...

you do something just half assed enough to
appear to get it right......


usually this happens on a late friday afternoon that the
joint will finally start to leak (after sitting all day)
and I get the call and usually its
on the other side of town at rush hour...




doing something just "half assed"
enough to last half a day
is a skill that cant be taught,

so dont worry about it......