re soldering solder joint

Hi all, have a leak in the central heating, found it - but it is in a
really awkward place right up against a wall with no pipe left to cut
off and fit a new fitting.
Question is, can I re solder the joint ? or is it not the thing to do.
I know the best option would be to replace the fitting, but it really
is a nightmare if I have to do that.
TIA
Reply to
Staffbull
Soldering up an existing fitting is very hard to do successfully. Just a slight bit of moisture in the pipe can cause it to leak again. If you can get the pipe really dry, then yes, it may be possible, but I would rarely try to fix an 'old' pipe by soldering. Maybe try one of the push fit fittings if access is limited? Alan.
Reply to
A.Lee
Yes, but you obviously need to drain down first. Oruse thiose freezer things. .
Well..I would certainly replace it if you can..unsolder it, pull it off with an oven glove, and see WHY it leaked.
Waving molten solder at the existing has less than 50% chance of success. You probably have an oxidated pit somewhere, that will need cleaning right up before putting a new fitting on.
Reply to
The Natural Philosopher
I've had intermittent success re-soldering existing fittings which are leaking.
Usually when I've come across a failed solder fitting, it's been due to the pipe not being clean enough, and the solder has not 'taken' to the pipe along a line which then forms a leak path. Adding new solder from the outside of the fitting is a rather hit-or-miss in this case. I usually re-work the joint from scratch. I wouldn't cut the pipe, I'd de-solder the old fitting and replace it.
I generally heat the pipe then pull the old fitting off using a set of water-pump pliers to grasp the pipe or fitting, and give it a gentle whack with a hammer. This will leave the pipework in place, with 'tinned' ends. It will be too fat to fit into a new fitting due to surplus solder, untill you heat the pipe ends, then quickly give a twist-and-pull wipe towards the end of the pipe with a damp cloth which will remove surplus solder.
You then need to examine the pipe ends to identify any 'tracking' where the solder has not 'taken' to the copper. Use wire wool, flux, and some spare solder untill the pipe ends are 100% perfectly tinned all the way round with no black 'tracks' where the solder has failed to take. Again, a wipe with a damp cloth to remove excess solder.
Then use a new fitting, flux the pipe, and solder it up. Don't allow the joint to move as it cools. Clean up the flux round the joint after it's cooled.
Although this sounds a bit laborious, I've had 100% success with this method. Note that the pipe must be totally empty of water before you can do any soldering work on it.
Reply to
Ron Lowe
Agree 100%. My experience matches yours *exactly*. The sole exception being a brand new joint of clean copper which leaks because you didn't put enough solder in the first time around.
Reply to
The Natural Philosopher
On Sun, 20 Jan 2008 06:38:45 -0800 (PST) someone who may be Staffbull wrote this:-
Of course you can. Whether that cures the leak, makes no difference or makes it worse is the more interesting question.
What happens depends on whether you can get the pipe dry (and to stay dry) while the joint is re-made. As well as draining the system you will need to eliminate any lying water and any water which might run in while working on the joint. How possible this is depends on the precise layout. I would put the general odds for a successful repair at 50/50, but your particular layout may reduce the odds dramatically.
If this doesn't work you may be lucky enough to be able to sweat the joint off easily. You may then be lucky enough, after cleaning/fluxing, to tap on a new solder ring fitting (this generally means heating it and the pipe up at the same time as tapping it on) and make it watertight.
Your options may be increased by cutting the pipe elsewhere and installing an extra joint, or dismantling existing joints and re-making them after re-making the troublesome joint.
There are usually no easy options in this sort of situation.
Reply to
David Hansen
As usual 'dynamo dave' has selected the most complicated and useless alternative. He likes windmills too.
Don't use a solder ring fitting, and clean the pipe using the 'blowtorch/wet rag', or indeed 'wrap with emery paper and scrub', techniques firts.
No need for hammers at all. Or windmills.
There are, but somehow you always prefer the more time consuming and expensive ones. ;-)
Reply to
The Natural Philosopher
Thanks, some varied responses!!, I think I might try and resolder it, I'll drain down first of course, hopefully the heat should boil off any water in the joint. I think it's worth a try before getting more extreme!!
Reply to
Staffbull
On Sun, 20 Jan 2008 15:29:47 +0000 someone who may be The Natural Philosopher wrote this:-
Excellent, personal abuse. Generally the resort of those with no better arguments. Do keep it up. I doubt if many people will be taken in by your postings, though there may be some.
Reply to
David Hansen
On Sun, 20 Jan 2008 07:33:34 -0800 (PST) someone who may be Staffbull wrote this:-
It is likely to drip out through the solder as you try and re-make the joint. Although a tiny amount of water might be turned into steam inside the pipe and not condense and run back any more than that will simply make the joint worse.
Reply to
David Hansen
On 20 Jan 2008 16:06:41 GMT someone who may be "Bob Eager" wrote this:-
I note that you have failed to provide evidence to support your assertion.
So, let's see, with reference to the posting I was replying to.
"Don't use a solder ring fitting,"
It is not clear why this is the "most complicated" option.
It is not clear why this is a "useless" option.
It is not clear why this is "the more time consuming" option.
It may be the more "expensive" option, if one has end feed fittings available. However, the average DIYer is probably going to find buying a solder ring fitting or two in a plastic pack somewhat cheaper than buying a bag of a couple of dozen end feed fittings.
"and clean the pipe using the 'blowtorch/wet rag', or indeed 'wrap with emery paper and scrub', techniques firts."
Those who take the trouble to read my posting will note that I spoke of cleaning, but didn't mention techniques. Thus the above comments are at best an elaboration of what I typed, not an indication that what I typed is "most complicated", "useless" or "the most time consuming".
"No need for hammers at all. Or windmills."
I mentioned neither piece of equipment. I did speak of tapping the new fitting on. Tapping can be done with a number of implements. Sometimes a new fitting will go on just by pushing, but one is not always that lucky (perhaps the pipe is a little oval or the end not perfect in some other way) and it may be necessary to tap it on. Often the pipe grips one was trying to push the fitting on with will be enough to tap it on, I can't ever recall using a hammer.
So, to repeat myself. Excellent, personal abuse. Generally the resort of those with no better arguments. Do keep it up. I doubt if many people will be taken in by your postings, though there may be some.
You may have the last word.
Reply to
David Hansen
You have (probably deliberately) widened this beyond the last post,
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That was an opinion expressed by TNP, and I agree. You often seem to select complicated and useless alternatives. And you do like windmills. You may not agree with that assertion, but it does not constitute personal abuse.
You seem to use the 'excellent, personal abuse' reply to write off anything you don't like. OK, you may consider 'dynamo dave' to be personal abuse, but I'd hardly class it as such.
Reply to
Bob Eager
Never got the OP thanks to blueyonder, but you have to make sure the pipe is 110% dry or the joint will fail. No blowlamp will heat it enough to remove the water. BTDTGTTS.
Reply to
The Medway Handyman
On 20 Jan, 15:23, David Hansen wrote:
My experience exactly mirrors that of Ron and David. I spent hours (four attempts) at trying to resolder a particularly difficult to get at joint over the Cmas NY period and all the leak did was get worse! I bit the bullet and gounged out a hole in the plaster and took out two stand off clips such as to get the sodding Tee off and found a small track at the bottom Complete and proper cleaning of the fitting and the pipe did the trick - should not have tried to save it So by all means drain down and have a go - you might be lucky but my advice is to do it right and drain down only once A "re solder" MAY only last as long as the pipe is not knocked! Chris
Reply to
mail
In message , Staffbull writes
One other method which I've used with success, where disassembling the joint would have been a major task, was to clean up the outside of the coupling/pipe, using a piece of sandpaper fed around the back of the pipe, check it's all clean round the back with a small make-up mirror, then wrap 'a fair quantity' of fluxed stranded copper wire around the joint and run solder into it. It cured the leak and never started leaking again in the four or five years that it was in place.
Reply to
bof
thanks, do you mean a fair few turns of fluxed copper wire wrapped around the pipe/joint, I suppose it acts as a catalyst capturing more sloder to stay around the joint? If I'm right about where the wire goes that is?
Reply to
Staffbull

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