On Thu, 5 Dec 2013 17:39:49 -0500, "TomR" wrote:

EXT wrote:
"TomR" wrote in message
...
I have an old-style, convector-type, wall mounted room heater that
has a small leak. It is similar to baseboard heat, but the heat is
provided by the hot water that goes through the convector element.

Here are some photos:
http://i44.tinypic.com/2a7izh0.jpg

http://i40.tinypic.com/v79r9y.jpg

http://i39.tinypic.com/28c3pk7.jpg

http://i40.tinypic.com/oa6wbc.jpg

The convector element has a very tiny leak near one end that I can't
quite locate with the convector connected up and working; and, even
with it disconnected I can't quite locate the pinhole or whatever
that is causing the tiny leak.

Buying a new replacement convector is not really an option since
almost no one makes or sells them. I could replace the unit with a
regular (used) cast iron radiator that I can get locally, and
probably get a regular radiator cover for it.

But, before doing that, I tried cleaning off the whole area with
emery cloth and solder flux with heat, and then tried heating it
with a MAPP gas torch and soldering the whole area. I don't know if
the element is all copper or some kind of copper/brass combination,
but the solder didn't really seem to want to adhere to the metal
very well. So, I tried just spreading around hot melted solder
wherever I could. The result was that the leak is now barely
detectable, but it still drips a tiny bit. My question is, is there some
type of soldering or brazing technique
that I could try to see if I could seal the tiny leak?

As long as the hot water is supplied by a non-potable water heater,
you could try some boiler stop-leak, similar to car radiator
stop-leak. The cure may be temporary if corrosion is eating through
the metal.

I guess that is an option, and someone I know did suggest that to me. I am
just not sure that I want to introduce any kind of stop leak stuff into the
whole boiler and heating system. But, maybe it would be worth a try.

If you can remove the item, a radiator repair shop may be able to
help. Just smearing flux on the old metal will not help the solder to
stick, you need to clean the metal first and that is exactly what a
radiator shop would before they try to repair it.

Interesting. Thanks. I had not thought about the possibility of taking it
to a radiator repair shop. I may end up checking that out. I did just buy
a garden-hose-to-pipe adapter thinking that maybe I can take the convector
off a gain, pressurize it with a garden hose attached to it and cap the
other end to try to find the exact location of the leak. Maybe a radiator
repair shop would do something similar.

A radiator shop will plug one end, connect air pressure to the other
end, and dunk it in a tub of water to find the air leak.. They will
then clean the area around the leak, heat the radiator in the repair
area, thoutoghly flux it, and apply solder, melting it on the hot
copper, NOT in the flame. If the solder does not melt on the clean
fluched copper it is not hot enough yet. Need to be carefull not to
heat it enough to melt the solder on existing joints. (and yes, I HAVE
soldered radiators - not my favourite job, but a home "convector"
should be easier - a lot less corrosion, no glycol to fuss with, and
none of those tissue-paper thin fins getting in the way everywhere.