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Taking apart really old cast iron radiator restoration?

josefrees Member Posts: 5
Hello World!

Recently purchased a house and it has a lot of old cast iron radiators in it, one in particular is not only in the way of a room restoration, but I am interested in how I could take it apart so I can floor the room in peace and also give it a good cleaning and restoration.

After some research I’m kinda stumped. It says American Radiator on the top and Corto Patented 1921 on the bottom. Does anyone know anything about these? I have questions but no point typing them out if no one knows anything about it. Thank you 😁


  • Fred
    Fred Member Posts: 8,518
    edited April 2020
    Steam or hot water system? They are a very common/popular radiator, American Radiator was the manufacturer, Corto is the style. If steam, You can disconnect the radiator from the supply pipe (and return pipe, if two pipe) and move it out of the way to re-floor and refinish the radiator but I would not try to take the sections apart. They have nipples in-between each section that can be damaged and leak. If a hot water system, you need to drain the system before disconnecting them. You can wire brush them to remove loose paint and then repaint them with a good quality latex or acrylic paint or you can send them out and have them sand blasted and repainted or a clear coat applied. If you have them sand blasted, be sure to wrap the supply/return fittings so they don't get powder coated or painted. They don't reconnect very well if the fittings get powder coated or painted.
  • Jamie Hall
    Jamie Hall Member Posts: 17,103
    Don't take it apart, unless it's leaking. They are remarkably hard to get apart -- and even harder to get back together.

    Disconnect it as @Fred says to move it out of the way (if your system is hot water, you are going to have the fun of draining the system and then refilling and purging it...). Be aware that it is heavy -- and inclined to fall over. When it is disconnected and sitting in the room somewhere, make sure that it is secured to something so it can't fall over. On you. Your kids. Your dog. Whatever... I suggest a good furniture dolly to move it.
    Br. Jamie, osb
    Building superintendent/caretaker, 7200 sq. ft. historic house museum with dependencies in New England
  • josefrees
    josefrees Member Posts: 5
    It’s hot water, already been disconnected and drained, moved a couple times and yeah, really heavy. We took the end caps (is that what they are called?) off to look in there (Lotta rust came out the bottom of one) and it’s rusty. Any way or reason to clean the inside out? Would you happen to know if this model radiator takes the threaded nipples or the push nipples? I would like to know for future reference...I found a bunch of brochures and stuff on here but finding resources on actual repair of these things seem to be hard to find...

    If I paint it, can I hand paint it? The walls in room have already been painted (dyslexic work order) so I don’t wanna get overspray.
  • Steamhead
    Steamhead Member Posts: 14,844
    No need to clean the inside besides rinsing it.

    As @Jamie Hall says, do NOT try taking the sections apart. They are threaded nipples and extremely difficult if not impossible to reassemble. Ask me how I know that..................
    All Steamed Up, Inc.
    Steam, Vapor & Hot-Water Heating Specialists
    Oil & Gas Burner Service
  • motoguy128
    motoguy128 Member Posts: 378
    Doesn’t matter. It’s not coming apart. Not without damage.

    Rust in the bottom is expected and won’t significantly impact performance unless flow is restricted. Most water movement is by thermal convection and so rust never gets flushed out. Flow rates in most cast iron radiators is fairly slow. Many used gravity flow originally (no pump, just convection) so piping is oversized. But by 1921 most had pumps.

    If it not leaking I see no point in doing anything other than flushing it.

    If they cool 180f water to around 160f at 68f room temp at the proper flow rate for your boiler size, then they are working fine.
  • josefrees
    josefrees Member Posts: 5
    Okay thanks everyone!
  • josefrees
    josefrees Member Posts: 5
    Before I forget, just for curiosities sake is there an age range for these? 1921 is just patent year right not a manufacture date??
  • PerryHolzman
    PerryHolzman Member Posts: 234
    When was the house built. The radiators were most probably cast 3-12 months prior to that.

  • josefrees
    josefrees Member Posts: 5
    One other thing, Fred said I can paint with latex/acrylic—they can handle the relatively high heat let off by radiator?
  • Jon_blaney
    Jon_blaney Member Posts: 136
    Remember, if you change the floor height, there may be a problem getting it hooked back up.
  • Jamie Hall
    Jamie Hall Member Posts: 17,103
    I've used, as I think I mentioned, Benjamin Moore's Aura paint, which is an acrylic, with no problems at all -- but it is a high end acrylic, not a bargain basement latex.
    Br. Jamie, osb
    Building superintendent/caretaker, 7200 sq. ft. historic house museum with dependencies in New England