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.
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?
Yes, but you obviously need to drain down first. Oruse thiose freezer
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.
I've had intermittent success re-soldering existing fittings which are
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
Note that the pipe must be totally empty of water before you can do any
soldering work on it.
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
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.
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',
No need for hammers at all.
There are, but somehow you always prefer the more time consuming and
expensive ones. ;-)
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
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.
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.
On 20 Jan 2008 16:06:41 GMT someone who may be "Bob Eager"
I note that you have failed to provide evidence to support your
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
"No need for hammers at all.
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
You may have the last word.
You have (probably deliberately) widened this beyond the last post,
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
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.
On 20 Jan, 15:23, David Hansen
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!
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.
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?