Securing 1/2" tails into new radiator

I'm a traditionalist. I used hemp and Boss White.

Christian.

Doesn't really matter, PTFE is easier to get and use though, & less messy. Use *plenty* of tape, really roll it on until the sharp threads appear more like corrugations under the tape. Take care with "Barlo" type rads with bosses let into the back panel not to swing on the allen key *too* much, it's possible to distort the panel if you're very ham-fisted. Make sure you wind the tape on the right way. Take care not to damage the mating surface (for the valve).

In article , jon writes

I vote for gel type sealants, available in a tube, easy to use and pretty such foolproof. Search or ask a plumbers' merchant for thread sealant:

I use PTFE tape, and give it at least 3 turns. One pair of valves which I bought a few years ago came with tails which were pre-coated with a PTFE-like substance, and which didn't need anything extra.