Radiator leaking

Hi all,
before calling up a plumber I thought that I might give it a try here.
Two of my radiators are leaking through the thread of the opening at the top. I don't know what this type is called so I put up a picture at
http://mysite.freeserve.com/weilbacher/DCP03563.JPG [34kiB]
I thought I could open it, smear some grease or some special glue on the thread and then close it again to seal the leak. The question is what type of stuff do I use and where do I get it? The guy at the small local DIY store didn't have a clue. The next bigger one is Homebase and there usually nobody has a clue -- in which department would I look there?
Perhaps someone here has a hint how to open it without getting the whole room wet. It is a bit difficult to get a bucket between the radiator and the wall...
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In an earlier contribution to this discussion,

Presumably there are 4 of these threaded bosses on the radiator - with radiator valves and pipe connections on the bottom ones. The top ones will have a blanking plug one side and a bleed screw on the other side.
If you turn off both radiator valves **, you can slacken or remove the upper plugs with very little spillage of water - but use some old towels anyway in case any nasty black gunge comes out. Once you have removed the plugs, clean up the threads with a wire brush, wind a fews turns of PTFE tape (obtainable from a plumbers merchant) round the threads, and screw them back in. This should fix the leaks. If it doesn't, take them out again, remove the shredded PTFE and smear some Plumbers Mait on instead.
** One of these will be a lockshield valve for which you will need a spanner or pair of pliers. If the system has been balanced, this may be only partly open. Count the number of turns required to close it, so that you can restore it to the same position.
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wrote:

I second that opinion and the advice given.
One thing you might want to be cautious about is that these leaks appear to be quite old from the stain marks. That may or may not represent a problem.
But be aware that if the CH system is quite old then you might find that the radiators themselves might start perforating. If that happens you'll need to be nice to Santa and hope he can get a new radiator down the chimney.....
PoP
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PoP wrote:

Yup, been there. I had a rad that looked like that. When taken off the wall the spot welds at the back where the panels are joined together were all rusty too.... Not worth repairing. New one saved me the hassle of painting the old one though
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BillR wrote:

Thanks all for the friendly advice. I will try with the tape first, before I take a more radical approach. The radiator itself doesn't look that old...
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wrote:

Boss White (and hemp thread) will do the trick. It's less than 1 per tub at B&Q.
sPoNiX
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Peter Weilbacher wrote:

Perhaps it is interesting for somebody else to know that none of the advice given here has worked for me. Over the last month I used - PTFE tape - Plumber's Mait - Boss White + hemp - Similar stuff I got in Germany + hemp and nothing worked. Plumber's Mait was the best, but still the radiators started leaking through the same opening within one week. This is probably my fault in that I handled the stuff incorrectly.
My solution was to put two component epoxy resin on the thread to really glue the connection. This has been stable for over two weeks now and the pressure of the system is constant since then (if I do not let the boiler switch itself off overnight, but that's a different story).
The caveat of course is that I really have to buy a new radiator if this starts leaking again, because I think that I cannot reopen this connection again to fix it then...
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Peter.
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It does of course depend on how old the rads are and whether they were any good to start with, not really the fault of the PTFE etc.. if the thread was never going to seal from the day it left the factory. It also may not be the fault of the thread as it could be corroding from the inside. If it was that bad I would have just changed the rad.
SJW
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