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Enlarging Radiators

I live in an old farm house. The large room in under radiated. I found a couple of identical ornamental radiators (to comport to the architectural integrity of the building) that were on the smaller side. I disconnected the threaded rods and separated some fins. I lucked out when the connecting collars (top and bottom) matched perfectly. I slathered the connecting collars and receiving holes with Real-Tuff and rejoined everything with longer connecting threaded rods & nuts.

Then came the water test under pressure (I used a garden hose w/ adapters because that would be higher pressure than a heating system). It failed miserably. I could actually hear the air escape from my joint instead of the bleeder valve

What am I missing? The nuts are adequately tightened (at least I believe so). I dissembled & reassembled radiators to make them bigger about 20 years ago and everything worked great. The only differences are: (1) I used Pro-Dope instead of Real-Tuff; (2) I never used the garden hose test before.

Clearly, it is not the pressure from the garden hose that blew out the Real-Tuff because I could hear the air escaping from the joint.

Should I take a wire-wheel brush to this joint (to remove errant paint or rust) and reassemble? Is there a down side to doing this?


  • Fred
    Fred Member Posts: 8,541
    There are brass push nipples between those radiator sections. You need to put new ones in. They compress to the mating section they came out of and they won't likely seal when used a second time. I think there are a couple places that sell new ones. Maybe someone will remember the source???
    Peter Rozano
  • Jamie Hall
    Jamie Hall Member Posts: 21,535
    You should not use a wire wheel on either the nipples or the mating surfaces in the sections -- you'll scratch them and then they'll never seal. You can clean them up, if necessary, with fine steel wool or emery cloth of something of that sort -- but I'd be surprised if the mating surfaces had much crud on them.

    And I don't remember the source for replacement nipples, either...
    Br. Jamie, osb
    Building superintendent/caretaker, 7200 sq. ft. historic house museum with dependencies in New England
    Peter Rozano