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How does this radiator come apart?

bruce_21 Member Posts: 236
This two pipe steam radiator has a leak in one section and I want to take it apart, remove the bad section and put it back together. I've done several in the past but they had rods going thru with nuts on the ends keeping them together. This one doesn't. How do I get it apart?


  • Steamhead
    Steamhead Member Posts: 14,429
    With extreme difficulty

    This one uses right/left hand threaded nipples to hold the sections together. You'd have to have a tool made up to fit an impact wrench, which usually involves several tries, then the nipples are frozen so badly they won't turn.... etc. etc. etc.

    In this case it's easier to replace it. Then use the old one to experiment on.
    All Steamed Up, Inc.
    Steam, Vapor & Hot-Water Heating Specialists
    Oil & Gas Burner Service
  • ChrisJ
    ChrisJ Member Posts: 11,549

    steamhead,  I had been wondering exactly how these worked.  9 out of my 10 radiators are made like this without the horizontal rods.

    Are these style radiators leak prone or pretty reliable overall?
    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
  • Steamhead
    Steamhead Member Posts: 14,429
    In all the years I've been doing this

    I have only seen one threaded-nipple rad that leaked. That was the rad on which we learned how difficult it is to take these things apart and put them back together.
    All Steamed Up, Inc.
    Steam, Vapor & Hot-Water Heating Specialists
    Oil & Gas Burner Service
  • bruce_21
    bruce_21 Member Posts: 236
    This one leaks

    not at any of the joints between the section but from one of them. So since it seems that taking this rad apart is a nonstarter can it be welded or brazed? Or would epoxy work if I cleaned it up with a grinder?
  • Steamhead
    Steamhead Member Posts: 14,429
    It's possible to weld cast-iron

    but not easy, from what I'm told. 
    All Steamed Up, Inc.
    Steam, Vapor & Hot-Water Heating Specialists
    Oil & Gas Burner Service
  • Rod
    Rod Posts: 2,067
    Try JB Weld

    As Steamhead has said it's probably better to just find a replacement. Welding cast iron can be done but isn't easy or a sure thing and in this case is quite likely to crack the part.

    You could try using JB Weld (a high temperature epoxy)

    which sometimes works quite well.  It's available in most auto parts supply  stores.

          The trick here is to do good surface prep. I would remove the radiator, turn it upside down and make sure that first it was completely dried out. I would then use a small round double cut carbide burr to clean out the crack and rough up the surface so that the JB Weld will stick. You should be able to get these at any industrial hardware store. On the internet you can get them from McMaster Carr.

    I would use a size SD-42 (1/8 x1/8 x1/8) or an SD-52 (1/8 x 5/32 x 5/32)   The 1/8 inch shaft will fit a Dremel Tool.  These bits are cheap so I would get at least two bits in case you break one. If you can get these bits use something similar.

         Take you time and grind both sides of the crack to remove any rust, corrosion or paint and expose bright metal. When you have done sufficient grinding then immedaitely mix and apply the JB Weld (don't leave it overnight as the bare metal may oxidize and this would interfere with the adhesion) Let the JB Weld set and don't move /reinstall the radiator for at least 24 hours to allow the epoxy to really cure.

         This is one of those things that either works or it doesn't. It doesn't cost much to try and it's much less likely to damage the radiator than applying high heat to it.

    - Rod
  • TomM
    TomM Posts: 233

    make sure you use a stainless wire brush and really clean the area before you add jbweld.  after grinding, cast iron has tiny dust particles on the surface and the jbweld will fail eventually.  Make sure its absolutely clean.  I've used JBweld twice, the first time failed, and the other has been good for 2 years after I researched the proper method. 

    Or you could braze it with nickel rod.  but cast iron is a b.  I tried to fix a cast iron railing, only for it to cool down incorrectly, and the cast itself cracked about 2 inches outside of the weld, past the heat affected zone.  never touched it again after that.
    beautiful Conshohocken PA
  • Luv'nsteam
    Luv'nsteam Member Posts: 272
    Leaking water rad

    I repaired a cast iron rad with plumbers putty.  To be sure it held, I charged the rad with 30 psi of air pressure and held it for two hours.  As previously mentioned, cleaning and good prep is key.  I also used plumbers putty to patch a leaky boiler tube in my old steam boiler.  It held for several years and in fact, did not fail before I ripped the old anchor out for a new one.

    JB weld is also outstanding epoxy.  My ex-stepfather used it to literally reline no-longer-available brake drums on an early sixties Dahtsun.  It worked and passed inspection (after he machined them down to spec).  I have also seen it used to repair gouges in cylinder walls and valve seats, too.

    If you weld the crack, you need an experienced welder, no question about it.  The prep work, kind of rod/welding method, how hot the cast iron is before welding and how long it takes to cool after the repair are all things I have heard of to make the repair stick.  I do not weld but know people who do.

    If you disassemble the sections, iodine (for cuts) eats rust like nothing I have ever seen.  Wire brush what you can reach and soak thoroughly for at least an hour, a day is better.

    Good luck and if you repair it, let us know how you made out.


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