Hello –
I am pre-assembling a combination of backflow prevention valve and a ball valve as a main shutoff for the house.
Both valves have 3/4 threaded female ends that will receive threaded 3/4″ male transitions for the 3/4″ copper pipes.
The entire assembly will be connected to the incoming citywater line and then onto the house supply line using compression fittings to avoid soldering problems with wet pipes.
My question is with the 3/4″ threaded fittings – is teflon tape wrapped around several times not good enough these days ?
I recall some comments about favoring the teflon paste instead.
Although the whole assembly could be easily removed I would rather not have to do that.
Which is more commonly used these days ? Paste or tape ?
Thanks for your help,
Alan
Replies
Paste is almost a must where there are any tiny orifices in the system, such as nat. gas, etc. or rotating parts such as high pressure hydraulics.
No problems with the tape for water, compressed air, etc where if a little piece of teflon tape from assembly gets in the sytem, worse you'll ever have to do it take a tiny piece out of a faucet aereator or spray gun.
Thanks, Junkhound.
I was more concerned with ability to maintain a seal.
If there is no difference between the two, I would rater wrap the teflon tape as it is a lot neater then messing with the paste stuff.
I did have to use gas rated paste recently for a gas range installation.
Thanks again for replying.
Alan
Teflon tape with a skim of paste to lubricate the threads so the tape stays in place better, and you'll never have a leak. Old plumbers trick.
Edited 6/10/2002 11:20:54 PM ET by KC
And find the thick tape, the pink brand is great. Joe H
And don't use too much. Twice around is plenty.
Uncle Dunc, what if he has Chinese parts? Takes about 5 or 6 wraps to make that junk seal. Joe H
I defer to your expertise. It sounds like you earned it the hard way.
definitely we all agree,
use both (tape + paste).
Worthless crap ain't it!
Wet,
I assume you mean the Chinese junk.
Personally, I use a pipe dope in stick form. I never touch it with my hands, and have never had a leak.
Just a thought...
James DuHamel
J & M Home Maintenance Service
I second the stick.. I get mine at True Value Harware stores.. I prefer the old paste over teflon. If the threads are wet when you put it on you may have problems..
Something to keep in mind is that teflon tape or paste are not for sealing threaded joints. They are a lubricant only.
The purpose of the lubricant is to allow the male thread to be tightened fully into the socket without galling.
There are products that are available for sealing; John Crane plastic lead seal has lead in it. In BC Canada, this product is approved for natural gas, but not propane.
Leak lock is a blue substance that hardens that is used for threaded refrigerant connections.
The old ammonia systems used a mixture of Litharge (which I think is Red Lead) and glycerine.
When I did service work on gas, I would use two wraps of yellow (thick) teflon and then go over the threads with a stick teflon. Never had any leaks.
KM
I've always liked teflon tape and teflon dope unless there is some super-critical orifice downstream then I use dope only. Guess I gotta find a stick of dope and give that a try now. Don't use Chinese fittings nor Chinese pipe wrenches. Life is too short to chase pinhole leaks, skin knuckles, and worry about political prisoner labor abuses.
David Thomas Overlooking Cook Inlet in Kenai, Alaska
Hey guys this is my first time at this site. Just wanted to add a couple more things I've learned about sealing tapered pipe. Whenever I connect new pipe, one or the other usually is fine. But when connecting new pipe to old pipe, it always seems to drip if I don't use both, especially as was pointed out about cheap pipe,(which seems to be more common these days), also since I've never had much luck w/ strap wrench's, I like to use plenty of both on shower head necks & tub spouts. I can tighten to the desired position by hand & I've never had one leak........ Look forward to future chat !!