I'm trying to insert a 6" section of 3/4" copper tubing in a heating pipe that runs through a channel in my house slab. I have the zone disabled, the water into the boiler turned off, the drain valve on that zone open and a spigot used to release air and facilitate draining open.But there is a constant drop of water in one side of the pipe that I intend to solder. I know I can't solder a wet pipe. I'm reluctant to try the old bread trick. Is there any kind of "solder", maybe epoxy that will work with the wet pipe?Suppose I fail in the repair attempt (this is the third time!). Is there some sort of clamp that will seal off the leaking joint?TIA.

You could try one of the new compression fittings that don't requiresoldering.'re sold at the big box stores.R

How can I solder a pipe that has a bit of water in it?

Jun 24, 2007 32 Replies

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mm 19 years ago

I know that, but I wasn't sure if he planned to ever use this zone again. I thought maybe it was out of use, but still leaking.

Okey dokey

Never tried that. I somewhat doubt it but I'm not sure, especially if the stuff was wrapped around the whole circumference of the pipe.

I don't think this would be a problem. I once used PC-70 to patch a leaking pan, and then, atypcially, I left the pan on the stove and boiled out all the water, and left it on the stove even after that for a while. After it cooled of, it still didn't leak, even on the stove.

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mm 19 years ago

It says that even for room temp and no pressure I bet. That's one of the times PC-70 is good.

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geohurley 19 years ago

I recently came across this website:

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They make what appears to be an epoxy-type bonder for joining copper pipe. It's about $13 from Amazon.com. I've never used it, so I can't vouch for it, but you can read a review of it at

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Doug Miller 19 years ago

What would make flare fittings a better choice than compression in this application?

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RicodJour 19 years ago

New style, Bob. Also new to the big box stores, new to residential construction (aimed at DIYer), new packaging and new to you if you've never seen them before. ;)

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John JJ 19 years ago

You might be interest in a product, that I came across just a few days from the Family Handyman magazine May 2001 issue (pg 95). The Topic "Plumbling Pipe Pluggers." They are available in:

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classicrock86 19 years ago

if there is a water flow than you have to try to close the flow... if it is closed but water still flows slowly... you can stuff the pipe with sandwich bread a couple of slices... this will absorb the water giving you time to do your soldering.

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Walter R. 19 years ago

Just stuff some white bread into the wet pipe, as far as possible. It will dissolve and discharge through the faucet when the water is restored.

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Stubby 19 years ago

I finally located a pair of 3/4" compression joints ($10 each!). But these require cutting the pipe stubs in the channel in the slab. So I decided to try the old bread trick with the existing stubs properly prepared and use a pair of standard sweat repair fittings. If it failed, I would have to do the cutting to use my compression fittings.

Luck was with me! The bread trick worked. Thanks to all that offered advice.

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Doug Miller 19 years ago

Missed the part about that being in a hot-water heating system, didja?

No faucet.

No way to get the bread out.

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clifto 19 years ago

If it gets stuck in your closed boiler system, you're toast.

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Clark 19 years ago

clifto wrote in news: snipped-for-privacy@remote.clifto.com:

Soggy toast?

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clifto 19 years ago

It ain't milk toast.

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