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Sealing an Oval Pipe Joint?

Harry_6 Member Posts: 133
OK, here's the deal: I recently replaced a one-pipe radiator valve and noticed when I took the old one off that the end of the pipe was slightly out of round, as if someone used too big a wrench previously (I know it wasn't me, as I cut the old valve off). I was concerned about the new valve joint sealing, but I used a bunch of pipe dope and crossed my fingers. It held for about a month, then started leaking. Anyone got a suggestion to improve the seal? Lots of tape and dope? The pipe goes into a tiny crawlspace, or I'd just bust the fitting below and replace it. P.S. - The old joint didn't leak with the original valve. P.P.S. - Interestingly, the original valve was replaced because it failed closed. Somehow the valve face became detached, the stem just spun without stopping when turned, and the face fell onto and sealed the seat. -HS


    EBEBRATT-Ed Member Posts: 13,834
    Your probably screwed. But a few things you can try but they probably won't work unless you have good access which you probably don't.

    Heat it with an oxy acytelene torch and using two hammers tap it back into round

    Put Never Seize on it and crank a fitting on it tight may force it back into round.

    Other than that, your probably you will have to cut it out and fix it.

    Don't start a fire if you go with a torch

    Or just take it off and dope the hell out of it and hope for the best. That should probably be the first thing to try.
  • nicholas bonham-carter
    nicholas bonham-carter Member Posts: 8,575
    Remember next time that the bonnet of the valve can be unscrewed so as to inspect the valve disk. That is a lot easier than removing the old valve, and the spud.—NBC
  • MilanD
    MilanD Member Posts: 1,160
    Cotton wicking on the pipe, monster blue tape over it, Blue-Block by Oatey 15707... Let it set for 12 h (closing a valve and keeping the steam out will do it). Cross your fingers.
  • gerry gill
    gerry gill Member Posts: 3,072
    permatex gasket sealer used as thread compound.
    Serving Cleveland's eastern suburbs from Cleveland Heights down to Cuyahoga Falls.

  • jumper
    jumper Member Posts: 2,123
    I've had some success with that epoxy for copper pipes. Haven't tried it on steam.

    Pack the connection. Heat both pipe and fitting so that they're too hot too touch.Then apply the epoxy.The epoxy will run into gaps. Hopefully the hardened epoxy will be elastic enough to accommodate thermal expansion/shrinking. There must be some goop which can stretch and shrink repeatedly. Finding it is the challenge.

  • hot_rod
    hot_rod Member Posts: 19,943
    I'd go with a thick viscosity epoxy like JB Weld. When cured it can handle 550°. It fills gaps nicely and goes off quickly.
    Bob "hot rod" Rohr
    trainer for Caleffi NA
    Living the hydronic dream
  • hvacfreak2
    hvacfreak2 Member Posts: 500
    I guess anyone posting here has something that has worked at least once. I'm going with Expando for this.

    Mechanical Enthusiast

    Burnham MST 396 , 60 oz gauge , Tigerloop , Firomatic Check Valve , Mcdonnell Miller 67 lwco , Danfoss RA2k TRV's

    Easyio FG20 Controller

  • Harry_6
    Harry_6 Member Posts: 133
    Thanks all. I had considered some of the options given, but no others. I'll probably start with blue tape and pipe dope, and if that doesn't work escalate to epoxy. After that, it's hard to go back. I may end up in a crawlspace breaking a cast elbow. For the record, I did think it might be a bad idea to burn their house down with a torch. Also, I've never had any luck trying to get the bonnet off, except sometimes using a torch (see preceding). I just loosened the nut and pulled the radiator away to see that the thing was stuck closed, although the freely spinning stem was also a clue. I'll see what happens and report back. -H