Soldering wet/dripping pipes

[Lobster]

Had to do some central heating repairs today (a leaking joint) which involved attaching a new piece of pipework on to an existing 10mm system. I had hoped to do a soldered joint, but having drained down the CH and cut off the tube where I needed to, I waited for for the offending tube to stop dripping water while I assembled the rest of the new pipework separately.

Still no sign of it stopping completely after about an hour; I was sure that if I tried soldering to it, I could be pretty sure that the joint wouldn't take due to an inopportune drop of water arriving. So I went for an ugly compression joint instead.

How do you get round this when making a soldered joint? I didn't want to bung up the radiator pipework with bread (as I've seen recommended) and although I didn't have my wet-and-dry vaccuum cleaner with me (as I've also seen recommended), I really doubt that would have worked since I was working at the bottom of a vertical drop from upstairs.

(I'm sure .andy would have had an answer...)

David

[A.Lee]

I dont think it is possible. Even if the water is not dripping, I have had it before where the evaporating steam has built up enough pressure to escape via the still molten solder. Nowadys I dry as much as possible, heat up the pipe around 6 or 8" either side of the joint to dry it out thoroughly, then when cooled down, and it is still dry, I solder it up. Where there is clearly visible water that cannot be stopped, I would not attempt a solder joint. Alan.

[George]

Have a pipe with you that fits over the copper pipe and suck the excess out,other than that heat the pipe up all the way along to boil off excess water.

[The Natural Philosopher]

two appraches, maybe three work.

First its important not to try and seal a pipe system that can have pressure.

Then you can either beaver away with the blowlamp while a nearby tap or valve steams merrily until the steam has gone, or sometimes pipe freezer will do the business. That will at least temporarily halt a drip flow.

[Dave Liquorice]

Any water about is bad news, either you simply won't be able to get the pipe hot enough for the solder to flow or the pressure from the steam will blow it's way out. The former is most likely in your case with a "flow" of water. Damp will be driven off but even a slow continuous drip is enough to keep the pipe cool.

That is the tricky bit any water will find the lowest point. You could try blowing or sucking the pipe to adjust the level of water further up the pipe above jiggling and possibly pulling it to bring the end down a bit or carefully using kitchen roll to blot up the pipe.

[John Stumbles]

...

Sometimes you can get the joint dry long enough to solder by sucking with your wet & dry vac from another pipe in the system.

[Stephen Howard]

Use plenty of flux and a large nozzle on your burner. The excess flux will protect the joint as it reaches soldering temperature and the large burner will easily cope with the odd drop of water.

If at all possible, solder the lower end of the joint on first before fitting the higher end to the joint.

Regards,

[Dave Plowman (News)]

If you've got a vacuum cleaner than can blow instead of suck that should dry them out - assuming you've stopped any new water entering the system.

[Dave Plowman (News)]

I've not found this at at all on a pipe which is continually dripping. If it's simply damp heat will sort that - but this sounds rather more than that.

[www.GymRatZ.co.uk]

That remindsme of a story about my first serious plumbing job im my first house, it involved a 200 bar diving cylinder and a single pipe CH system completely blocked with chipboard fibres where previous occupants had made a chipboard lid for the expansion tank and some snug fitting hose pipe...... ;¬)

A _real_ plumbers torch thing can make a huge difference. One of my DIY regrets was not buying one 10 years ago!

:¬)

Pete

[The Medway Handyman]

Could you specify what a 'large burner' is & possibly a link to a supplier?I have a Taymar blow lamp & no way would it ever get hot enough to cope with even a trace of moisture, let alone the odd drop of water.

[The Medway Handyman]

Could you suggest a make & model for a 'real' plumbers torch please?

[George]

Taymar blowlamp is crap and a waste of money in terms of buying gas canisters,get yourself a propane torch.

Great for paint stripping,soldering copper pipes...£10 for a propane

6.5kilo.

[robgraham]

Screwfix

've used these on couple of occasions and found them excellent. You'll get 20 to 30 minutes worth of frozen plug out of one tin.

Rob

[Stephen Howard]

It's worked for me - but I did use quite a hefty Sievert nozzle. I think if it's much more than a drip every couple of seconds then it might get rather tricky.

I'm wondering whether or not it might be possible to shove a soluble tablet up the pipe - something like an Alka-Seltzer? Maybe two of them back-to-back - they'd hold the drips off long enough to allow the joint to be soldered and then they'd dissolve when the water was turned on. Might have to sand them down a bit to get them to fit.

Regards,

[www.GymRatZ.co.uk]

Dunno if a real plumber would class it as a pro. job as I got it from B&Q however...

with a can of MAPP gas. It's so quick you actually use very little gas and it doesn't take an age to warm up through that whole orange, yellow, spitting/popping flame routine of your typical blowtorch. I presume replacement canisters would have to come from a Plumbers merchant or something specialist as (at the time) they weren't a seperate B&Q part.

I think it would only be B&Q Warehouse that sell them, or no doubt other on-line places like screwfix.

No doubt others will be able to comment on other such articles.

Cheers Pete

[Stephen Howard]

Well, I can tell you that it's a Sievert as all my soldering kit is that brand - but as to the nozzle size, it's the second largest one I have out of half a dozen....and it's about an inch in diameter. It's a proper gas gun job, with a separate gas supply and hoses etc. rather than a handheld jobby ( though I've see a few of these with quite large nozzles before ).

Funnily enough I got that nozzle at the tip - attached to a decent handle too.

Regards,

[Tony Bryer]

An old plumber I knew said that bread was ideal for this - but not advised if you're feeding something with small orifices

[geoff]

In message , George writes

proper tool for the right job ...

[The Medway Handyman]

bits of plumbing. Taymar gas canister lasts me 6 mths +. Dont really want a bulky 6.5 kilo cylinder on the van either, takes up too much space.