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Copper vs steel for cast iron rads

Thank you Mike for sharing your opinion. I'm leaning towards black steel.


  • Scott Lind_2
    Scott Lind_2 Member Posts: 2
    Copper vs. steel for cast iron rads

    We will be re-installing a bunch of cast iron radiators in a home that has been completely gutted. One guy says pipe with copper and use dielectric fittings. The other wants to use steel.

    What are the advantages/disadvantages of the two materials? I'm looking for the longest life installation here, not lowest cost.

    Thanks for any opinions!
  • Bryan_5
    Bryan_5 Member Posts: 270

    See the following thread may give you some insight
  • Mike T., Swampeast MO
    Mike T., Swampeast MO Member Posts: 6,928

    Hard to beat black steel regarding durability in a closed hydronic system. While it might not last centuries like the older black iron I think you can consider it a "permanent" material.

    Copper has a pretty good track record as well I believe but since it hasn't been used for as long (commonly at least) it may or may not have similar life expentancy. At least oxygen diffusion isn't an issue with either ;)

    One disadvantage I could see with using copper in standing iron systems is mechanical damage--particularly if copper is run all the way to the radiators. While they're not removed often and don't tend to want to move copper is quite soft and you'd certainly have to be careful when installing/removing those massive things... As long as the angle unions and valves are brass (yellow brass in particular?) I don't think there would be a problem with dielectric corrosion when using copper.
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