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.
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.
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:
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.
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.
First clean with the emery cloth. Then clean with Muriatic acid.Do this OUTDOORS. Fumes are bad to breath. Also use rubber or plastic gloves. After that rinse with water. Then use silver solder and the Proper flux. This requires a higher heat so use a MAPP gas torch. I have done this on copper pipes. WW
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.
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.
First clean with the emery cloth. Then clean with Muriatic acid.Do this OUTDOORS. Fumes are bad to breath. Also use rubber or plastic gloves. After that rinse with water. Then use silver solder and the Proper flux. This requires a higher heat so use a MAPP gas torch. I have done this on copper pipes. WW
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Okay, thanks. "Maybe" I'll try that, but I'm not sure yet.
More heat. if the solder isn't sticking, the copper is either not clean enough or not hot enoug - most often the latter if working with a standard propane torch. A high swirl torch on propane, or better yet, MAPP gas will produce the required heat - a normal old-school bernzomatic straight flame torch on propane doesn't stand a chance.
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.
Just an interim update. . . . ,
I first went to a local welding and metal fabrication shop. They are always very nice and helpful there. They looked at it and weren't sure if they could do what I needed. But, they also suggested going to a radiator repair place and said that what radiator repair places do all day long.
I found and went to a radiator repair shop. The guy said that they can fix it. They will use a "glass bead machine" to clean the entire area, then use special liquid (not paste) flux, then do the solder/fix, and then pressure test it to make sure it is fixed. He said that they will do both ends even though just one end has the leak right now. And, the price will be "no more than $89" to do both ends.
It should be ready in a couple of days and I'll post back how it all turns out.
Had the same thing done on a leaking coil. Radiator shop charged $85 so that is right in line.
Sounds like a very reasonable approach and solution. Let us know the results!!!
Will do. I assume that I will get it back from the radiator shop tomorrow (1/2/2014) or Friday.
I would not have thought of taking it to a radiator shop until someone here suggested it. The plumbing supply place that I go to near me (who just happens to sell used cast iron radiators) said that those old convector radiators can't be fixed once the develop a leak. I believed him, but luckily decided to post the question here this time. The same place also told me that a couple of years ago when I had another convector that had a leak, and I ended up just replacing it with a used cast iron radiator and new (used) radiator cover -- that I bought from the same plumbing supply place. And, I put the old convector out front for the scrap metal people to take for free and it was gone in less than 30 minutes.
When I went to the radiator repair place a few days ago and I said that I understand that the convector radiators like the one I have really can't be repaired once they leak he said, "Who told you that?" Then he proceeded to tell me how they repair them, and ones that are much larger than that, all the time. He explained in detail how they do it and he said that even if the leak is in the tubes with the fins on them, his guys just spread apart the fins, do the repair, pressure test it, and it's fixed. He said that usually the only time that they can't realistically be repaired is if the tubes have a big split in them (I guess from freezing when left in a house with no heat during winter).
So, I learned something new here -- which I do all the time. And, hopefully it will work.
The alternative to this repair would be to buy a used cast iron radiator (about $175), a used radiator cover, a radiator valve and some plumbing fittings, open up the ceiling below the existing convector radiator, install the used cast iron radiator from below and above, install the new/used radiator cover, patch and repair the holes in the ceiling, and repaint the patch job.
Instead, for about $89 the original convector should be fixed and I can just connect it back up and it all should work.
Back in the late 1960s I was the supervisor in the radiator department. We built and repaired such units from 6" x 1" to 4' x 20' Tube were usually copper but we did brass and cupro-nickel for high pressure. Good thing you checked around and saved a lot of time and money.
Interesting. When the guy at the radiator place was telling me that they repair them all the time, he did say "all sizes" and he said "even ones like this" -- raising his hand up over his head meaning 6 or 7 foot high units. I never knew those existed or, if they did, that what I think of as an auto radiator repair shop would fix those or fix what I have.
Air conditioning and refrigeration guys fix leaks in copper, as part of the job. Might not totally be same as what's needed, but the similarities are there.
The small coils are for room heaters, the big ones go into huge systems for auditoriums, shopping malls, theaters. We also made some for naval ships that could handle high pressure steam.
Here's the final outcome: -- it's fixed. The radiator repair shop only ended up soldering the one end that was leaking, and the cost was $79. I connected the convector back up and it's working fine with no leaks.
Here's a photo of the solder job that they did on the end that was leaking (not pretty, but it worked):
And, here's a photo of the other end that wasn't leaking to show how the ends looked before the solder job:
Thanks again to everyone. Posting the question here got the problem solved for me.
Like you said, not pretty, but who cares, it's a radiator. It's good to know the collective wisdom here does save time and $$.
Piss poor job. Repeat failure is not a matter of if, but of when.
Looks effective, to me. Thanks for sharing. Nice to know how things work out.
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