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What are the chances of successfully

Breaking a fitting loose on a 1.5" dry horizontal return that was piped in 1933?. I want to change about 20 feet of horizontal dry return when I switch out the boiler this spring. I could just leave it, but moving it closer to the outside wall would give me a little less head bumping when I'm in the basement!

Thanks, Joe


  • Duff
    Duff Member Posts: 61
    things you have to know

    Can you tell the difference between a steam fitting and a steel fitting?  Steam fitting are a cast fitting and can break when you hold back with one hammer and hit the fitting with the other. Steel fittings have to be sawed off close to the outer pipe wall and then split by driving in a small flat chiesel untill the fitting splits being carefull not to hit the threads with the saw blade. It can be doneyou just have to be careful...........good luck Joe
  • crash2009
    crash2009 Member Posts: 1,484
    edited February 2012
    Pretty good

    I had mine re-piped a couple years ago.  The guy that did mine must have recognised that my elbows were cast iron.  He just beat them with a hammer until they split.  You can see in the pictures where he was aiming.  I was allowed to watch but I had to wear safety glasses, even standing back 10 feet.  When they finally split there is a lot of pieces flying around.
    STEAM DOCTOR Member Posts: 2,002

    I always use a grinder. Cut into the hub about 98% the depth of the hub. Do this on either side of the the hub. Make sure that the cut extends beyond the end of the pipe/nipple. Make a third cut to connect the first two cuts. The third cut should be at the point furthest from the hub and should cut all the way through the thickness of the fitting. After the first two cuts are joined take a hammer, give a few whacks ant the fitting will come right of. With a little experience it shouldn't take more then a few minutes per fitting. Of course take all necessary safety precautions when using a grinder. Good luck!
  • Hap_Hazzard
    Hap_Hazzard Member Posts: 2,846
    How to tell cast fittings from malleable

    Trick question. They're all cast. Malleable fittings are cast fittings that have been annealed, so, unless you can see the graphitic microstructure, you can't tell by looking at them. That is, unless you see tool marks all over them. That's a dead giveaway that you're looking at a malleable fitting.

    Malleable means "able to be hammered." Hey! I'm malleable! I just got hammered the other night!

    No, not that kind of hammered. It means it can be beaten permanently out of shape without breaking. So if you whack the edge of a malleable fitting with a hammer, or drive a cold chisel into it, it will leave a dent. If it's brittle cast iron, you might knock a chip out of it, but it won't deform.
    Just another DIYer | King of Prussia, PA
    1983(?) Peerless G-561-W-S | 3" drop header, CG400-1090, VXT-24
  • Charlie from wmass
    Charlie from wmass Member Posts: 4,322
    Cast fittings as they are known

    Have twice the thickness on the shoulders of Malleable as known in the trades. I use a diamond wheel and a thin chisel to break the fittings. It splits the cast iron fittings and spreads the malleable ones. All safety gear is required. Tighten the fittings to loosen them also works when properly done. The easiest way to repipe iron is to hire a profession to do it for you. Lost ink but no lost blood that way.
    Cost is what you spend , value is what you get.

    cell # 413-841-6726
  • ChrisJ
    ChrisJ Member Posts: 15,774

    When we piped in my boiler a few months ago we cut the pipe around an inch from the fitting and then using a chisel, a hammer and some effort hammered on the side of the pipe with the chisel until it folded in on it self.  It then unscrewed right out of thr fitting leaving perfect threads. 

    We did this on two 90 deg elbows with zero damage to the elbows.  I then used Blue monster PTFE tape and Megaloc dope together on the new pipes to make sure I got a good tight seal in the 80+ year old threads.
    Single pipe quasi-vapor system. Typical operating pressure 0.14 - 0.43 oz. EcoSteam ES-20 Advanced Control for Residential Steam boilers. Rectorseal Steamaster water treatment
  • Long Beach Ed
    Long Beach Ed Member Posts: 1,211

    The problem with beating fittings is that it can break other things and upset them, causing leaks.  

    While you are limited to tools that you have on hand, we try to never beat on anything that's 80+ years old.  We learned that the hard way.  

    We always cut the pipe with a Sawzall  holding the pipe with a wrench to minimize vibration, and rethread the stuff with a Ridgid 600 or 700 threader in-place. 

    Of course, thinking wishfully we try to open old unions first, but that only happens in maybe one out of ten tries. 

    When all else fails, cast elbows do break fairly easily with a lump hammer when hit in their thin area.   Usually two or three hard blows breaks them.  We used to do it that way, but later down the road we sometimes encountered other leaks in the system caused by the vibrations and beatings. 
  • ChrisJ
    ChrisJ Member Posts: 15,774


    I was able to remove two unions by heating them with a torch and hammering on them, after that they spun apart so easy I wouldn't have needed a wrench if it wasn't so hot.  Problem was the two unions were in the wrong spots anyway so I still needed to do more work.
    Single pipe quasi-vapor system. Typical operating pressure 0.14 - 0.43 oz. EcoSteam ES-20 Advanced Control for Residential Steam boilers. Rectorseal Steamaster water treatment
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