Gauge fittings, pipe dope, teflon tape or bare?

I would use Teflon Dope. Keep it away from anywhere near the end of the nipples. This is a "Must Do" for racing engines and nitromethane and nitrous oxide as any Teflon tape flakes will jam up and destroy solenoids (Exactly the problem you will have with welding equipment.) Now this is just a carry over from what I do from one discipline to another and I have yet to have any problems with any of my welding gear or fuel injection systems, in essence the same mechanical principles apply so It works for me and is mandated by racing sanctioning bodies (not that they add any credibility to this) but 2500hp of alcohol and nitromethane being pumped through 8 little nozzles on a bug-catcher and one goes lean- engine goes boom and a pissed off client is either on fire or coming after me with a baseball bat. Teflon dope Teflon dope Teflon dope..... I do think acetylene has a different story- one of the Journeymen can chime in on that one or I may be mistaken, it's never crossed my path yet so I don't know.

Rob

Fraser Competition Engines Chicago, IL. TAFC/4308 TAD/334

"Thor" wrote in message news: snipped-for-privacy@4ax.com...

Thanks for the reply and I think I should clarify a bit.

This is for a mig welder using C25 or argon.

The male/female 1/4" adaptor I made get threaded into the valve body of the flow gauge. I made the adaptor so I wouldn't mess up the threads in the valve body by changing fittings so often, a better safe than sorry sort of thing.

I will give the teflon tape a go as it would be easier to clean up than pipe dope.

To add a question, what sort of pressure is on the lines exiting a valve/regulator at 20 CFH? I don't have a tank as yet, hoping on next week. I am also not quite set on the small tank or the larger tank,err.

Thor

Contrary to popular belief, teflon pipe dope and tape are not sealants. They lubricate the threads allowing the pipe fittings to be tightened tighter, allowing the pipe threads to do their job. A small amount of paste does the job, and like Rob says, bits of tape can cause a lot of damage.. I have even seen teflon tape used on automotive brakes. It can't help at all in a compression fitting.

A-men, Ive seen people try to use it on the nipple for an O2 bottle

IIRC the pressure is about 25 psi on the high side of the orfice. The pressure where it exits is probably only two or three psi, maybe as high as ten.

Dan