We have a pinhole water leak under our kitchen sink under the concrete slab of our house, we dug a big hole under the house because we didn't want to remove our countertops, cabinets, then break out all the concrete so we dug a big hole tunneling under our house under the footing to the 3/4' copper pipe where the hole is located. My question is how come every time we light the torch, when we raise it up to the pipe it goes out. For some reason we can't get our turbo torch with mapp gas or even propane it won't stay lit!! Can someone help please?

How are you going about fixing the leak? Are you cutting the pipe and using a coupling, or just trying to patch the hole? Remember, copper pipe under ground needs to be either flared, or brazed, no soldering here okay. Good luck and please let us know how things work out.

Excellent point Lee (MGD77)... pipe really should be flared or brazed as you suggested... ;)

Teecee, easiest will be to purchase a flaring tool and some flare nuts and couplings and flare the tubing with the tool... see video below.

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Questions? Let us know, OK?

Mark

I made the hole a little bigger then I was trying to heat up the pipe hot enough to silver solder the hole but the torch keeps going out! Is it because there is no ventilation under the house?

I made the hole a little bigger then I was trying to heat up the pipe hot enough to silver solder the hole but the torch keeps going out! Is it because there is no ventilation under the house?

Yes, Flame eats up all oxygen and dies.

You will have heck of a time fixing that pipe under the slab. Pipe may not be perfectly round do coupling will probably won't fit. As our Experts suggested above, flaring may be the best way to go. Can you snap a photo of it and post it for us ? Thanks... Milo

No soldering underground? Didn't know that.

Flaring? Hard or soft copper?

You are not going to silver solder (hard solder or braze) with a Mapp gas torch.

Hi guys...

The copper tubing underground is extra thick-walled Type K tubing if in states like Massachusetts (usually sold in rolls). Otherwise, all other codes require minimum Type L tubing undergound... also sold in rolls.

In my area you can Braze or use flare fittings... either is acceptable, but yeah, no soldering allowed!

Teecee... buy a flaring tool and flare coupling and nuts to stay within code and quickly finish the job. See video. You don't want to be back doing this again in 3-4 years, OK?

Mark

I've been following this thread and, as usual, learning. I would not have guessed that a flared coupling is considered more reliable than soldered joints. Is that the case?

Yes, a flared joint cannot blow apart as the flared section of the tubing cannot pull through the flare nut itself.

A solder joint, on the other hand, can break from simple ground movement associated with thaw/freeze cycles or improper bedding of the tubing, etc...

I agree with everyone on that the flared joint they are the better application and can stand for high pressure, you can find some flared tubing in most aircraft hydraulic, Fuel, Water and fire extinguishing systems which are high pressure high as 3000 psi, Thanks.

Regards,
John