I have a home in central NJ built around 1950, with cast iron hot water radiators. I've gotten myself into a quandry with one of them. Here's the story.
A few years ago I noticed the radiator in an upstairs bedroom only got lukewarm. I had a contractor look at it while he was there to fix the boiler, and he observed that it was WAY to big for the room, and if he made it work right I'd get roasted like a Thanksgiving turkey. Since the room got warm enough as long as I left the hall door open during the day, so I took his advice and left it alone.
Now I'm remodeling the room, and the radiator had to come out, so I wanted one the proper size. At first I thought I would have to replace mine with a restored, used unit of the proper size. But info I found on the web suggested I could shorten and refurbish the one I had. It's a five-column, 33 inch high unit which had 20 sections. Someone did a heat loss calculation for me and determined I only needed 9 of those sections. I unbolted it split it apart using some wedges I cut from 2x4s. It came apart with little drama. I removed the extra 11 sections from the middle, and took to two ends, now with 4 and 5 sections, to a restoration shop.
Here's where things got a bit off track. On the web I found radiator spe******t companies (located nowhere near me) that said they could shorten or lenghten their radiators as needed. I managed to find one shop that restores radiators about an hour and a half away, so off I went. Turns out, this particular shop restores lots of radiators but doesn't resize them, and nobody there had ever put one back together. (This was a communication failure on my part.) So now I have two freshly restored radiator halves that need to be re-united. I haven't called my heating guy yet, but I don't know if he's ever delt with a situation like this.
An older gent I met at the shop said I need to put a sealer on the joint. I'm not sure what to use. I still have the surplus sections behind the house. The sections have male and female fittings, and the male portion appears to be cast or welded to the section. I don't see any evidence of sealent. When I fit two sections together they slide in with only about about 1/16 inch left to go. I'm thinking (hoping) tightening the nuts on the threaded rods will pull it the rest of the way together.
So what should I do next? Does a sealer need to be used, and if so, what type? Should I call my heating contractor and ask him to put it together? (I'll need him to rough in the new copper lines too.) Would the average heating guy think this is no sweat, or will he look at me like the Buick parts counter guy when you ask for a taillight for a '72 Opel Manta? Your advice is much appreciated.