Steam Radiator thread sealant?

[fnord]

Is there some sort of thread sealant that should be used when hooking up steam radiators?

Thanks, John

[Speedy Jim]

On the faces of the union? They were intended to seal without any sealant, but on an old system you can put a thin film of pipe dope or even RTV on them.

On threaded parts (nipples)? Yes.

Jim

[Edwin Pawlowski]

Teflon tape and/or pipe dope

[Lawrence Wasserman]

Yes.