bad threads on black iron fittings

J. Francis

I recently was doing a boiler inspection on some high pressure steam boilers (125 psi) and had the experience of finding three or four nipples that had bad threads (very difficult to remove) where the nipple entered the boiler. These were replaced last year and were installed with thread compound. I have heard of techs using teflon tape with never seize compound, is this correct? If not what do I do to prevent this in the future?

Thanks for the help
J. Francis