joints & teflon

Unknown

Thanks Guys -

I'd heard others say that they didn't use teflon on gas before but they didn't know why - Just that it didn't use it.

Mike Mumma

pipe joints & teflon

Does anyone know WHY you should'nt use teflon tape on steam-pipe joints? Is it ok to use dope with teflon in it, or should PTFE simply be avoided all together?

Thanks!

Mike

Ken_40

Say what?

Whoever said teflon tape is not for steam piping? It is THE dope of choice in that application!

The oils associated with almost all paste pipe dopes, including those with teflon, are a bad idea.

The reason? When heated, the stuff "drools" into the pipe-work and back to the boiler as steam and condensate make their trip floating on the surfaces of the pipes inside.

Oil and oil-like compounds in a steam boiler (or water for that matter) are bad news and cuase priming, surging, and a myriad of contamination issues.

The only complaint I ever heard from teflon tape is that it is so slippery, the cast iron fittings may be "cracked" from the "tension" the nipp tapered thread can exert on the fitting. Being 6'5" tall and 225 lbs., I was never able to exert enough "tension" to witness the threat/rumored/"crack", but maybe a 5-foot extension bar on a Rigid 48" on a 3" nipp wasn't that forceful?

Mike Mumma

Who said it?

I read it in TLAOSH. Per Dan, he only reiterated what was, at the time anyway, being spoken by the boiler MFG's. What you say about the dope, however, makes sense.

Mike

Paul Fredricks_3

No teflon and no dope. That leaves us with dry sand.

What page in TLAOSH was that on?

Ken_40

Mike,

I think you're confusing teflon tape used in gas piping. Perhaps, teflon tape on fuel oil as well. Both are verboten, or should be.(;-o)

Teflon tape is the dope of choice on any steam app I can dream of.

Mike Mumma

teflon tape

Paul, I do not remember what page I read it on. I just took a quick glance through the "Steam Bible" and could not find it. I will look again tonight when I have more time. However, please note that I was trying to discover the "why" it is not good to be used. But, if all you fellows that install these wonderful systems use teflon tape and have no issues with it, I see no reason why I should avoid it. Thanks to all who chimed in.

Mike

Unknown

Ken
Teflon on oil piping, I understand - it will destroy the fuel pump, but teflon on gas piping? I didn't know that.

What is the reason?

EBEBRATT-Ed

Some do not like teflon tape because of its ability to get inside the pipe and potentially get stuck in fuel valves (gas or oil) and cause them to leak by.

Oil pump and burner manufacturers don't allow it. On gas it isnt a code issue as far as I know.


ED

brucewo1b

Because

those little strands get into gas valves and rgulators causing havoc.

Ken_40

Bruce,

You and Ed nailed it.

The "fray" gets chased down the pipe by the gas flow and despite a screen filter on the inlet of most gas valves, the pilot would clog if anything got through.

The fact that teflon tape never "dries" or makes a joint rigid over time, is nice for steam pipes, but not an oil filter, or gas pipe etc. These fittings/components should be somewhat rigidly attached, not "swinging" around. This, in addition to the "fray" issues (allegedly "fixed" by avoiding the first two threads to go "bare") is the basis of leak-city pipework IMO.

brucewo1b

Thanks Ken

and I agree on the non swing joint effect in gas and oil piping, just hate that swinging oil canester on the outlet of an oil tank.