Sealing malleable iron fittings for compressed air

[Bill Edwards]

Swak or loctite. Tape is bloody dangerous if you use too much

Why?
If you use too much could it lead to tightening of the joint without proper thread engagement (thinking tapered threads here) allowing the joint to then blow apart under pressure?
I'd think you'd have to use a pretty thick layer to achieve that...?

 

[addjunkie]

It does happen hence why tape banned in some industries

 

[Bill Edwards]

Right makes some sense then. Sounds like common sense is probably needed - putting half the reel of tape on a 1/2 bsp fitting might be a problem, thinking about it there probably have been people who've done that...

 

[addjunkie]

Ive seen it on more than one occassion. Worst ive seen was maleuabke iron fitting about 10 wraps of tape, ready for a 200 bar nitrogen leak test.

Air went blue.......outcome maluable iron fittings dont float. The person hopefully now knows better.

 

[Bill Edwards]

200 bar - wouldn't want to be near that when it went!

Thinking about it, while I won't say it can't be done I suppose that for the pressures involved in semi professional air systems (up to 150 psi) you'd have to really go over the top with tape to make a fitting blow apart?

 

[dannyp]

usally the PTFE comes out when the joints half knackerd, i've temparly sealed some very poor hydralic fittings with it, mosty by useing all of whatever was left on the roll i managed to find. to the point where you cant see most of the threads anymore