soldering on wet pipe

[jacobball]

Hi folks

JUst a quickie - I'm going to be soldering a fitting in my bahtroom (2 fittings) - and the pipe is still quite wet - is there any knack to make sure the solder runs properley and doesn't leak - in the past I've done a bit of soldering but on completely dry pipes.

Thanks for your help

 

[45yearsagasman]

It is not possible to solder with water present.You must ensure water is not present during the whole process.

 

[jacobball]

Thanks for your reply

How do I solder it then? Basically it's a radiator flow pipe - the system has been drained down, but there's still a bit of water in the pipework - the pipe is still wettish - I've tried drying it but some water just returns.

Will heating it help? ... any tips?

 

[JohnD]

solder all the new, dry pipe first, and make your final connection to the wet pipe with a compression or push-on joint.

You may be able to make the water run out of the pipe by bending it down and holding it it for an hour or two, then bending it up and putting the blowlamp on it a metre from your proposed joint. If it is still steaming you can't solder it.

After you have tried a few times, you'll believe us.

 

[jacobball]

well I had a boiler swapped a year or so ago and the joints were all soldered and they were still "wet" pipes - just wondered what the technique was?

 

[JohnD]

sometimes a powerful vacuum cleaner or compressed air can move the water away from where you are working

but wet pipes are a common cause of poor joints and leaks

 

[IJWS15]

If the water is still flowing, even slowly - stop it. If you can't soldering is almost impossible.

If you can prop the pipe so the end is high and any water runs back down the pipe.

Dry the pipe end with heat (gas torch), clean the end and solder.

If the water gets back to the end between drying and cleaning see first line above. If it continues to steam (as posted above) as you dry it see first line above.

If the joint is at all wet the solder will not seal it. You will learn by trial and error that to solder the joint needs to be scupulously clean and scrupulously dry, nothing in it but flux before you put the heat on.

 

[Richard C]

well I had a boiler swapped a year or so ago and the joints were all soldered and they were still "wet" pipes - just wondered what the technique was?

There is no technique; you cannot solder wet pipes, water in the pipe will just take away the heat & prevent the solder running. Various tricks you can try (as mentioned) to get rid of the water but if the pipe steams when you apply heat, it will contaminate the solder joint & even if it doesn’t leak initially, there is a huge risk it will before too long. Unless you can guarantee a perfectly clean & dry joint for soldering, use a compression fitting.

 

[JohnD]

After you have tried a few times, you'll believe us.

 

[jacobball]

Just soldered the 2 fittings and all is well - I wiped the pipes inside and outside dry clean, then cleaned them with wire wool and fluxed them up as normal - al is well. thanks all for helping

 

[Jake1886]

You need an open end, plenty of flux, mapp gas and give it plenty of heat!

I've done loads and it works most of the time. Then again sometimes it just ain't gonna happen

 

[Richard C]

I've done loads and it works most of the time. Then again sometimes it just ain't gonna happen

Those are the ones that bite your ass & you have you dig up the floor for!

 

[Jake1886]

Haha your right there Richard.

And why is it always a Friday evening?!