Teflon tape or pipe dope

chickenboo

I've read some of the posts in this forum and many plumbing books. Sometimes, I see recommendations to use tape, other times, to use pipe dope. I don't see any kind of pattern about when to use what.

Are there applications where teflon tape is better than using pipe dope (pvc, copper, iron, steel or brass / straight or tapered threads)?

Ron The Plumber

Tape should be used when dealing with plastic fitting mainly plastic male thread water fitting, reason being if you use pipe dope on plastic male threaded fitting for water supply, the dope tends to make the threads too slick causing overtighting of the fitting.

Now on plactis drainage fitting, pipe dope if fine to use.

Now we use a combo of teflon tape with pipe dope on all metalic male water fitting and pipe, this ensures it will have a possitive seal each and evreytime.

carlfino

Have you ever found situations where pipe dope caused any kind of chemical reaction with a plastic component that led to the part failing?

Ron The Plumber

Nope not in 25 years.

mdshunk

Consequently, Rectorseal #5 is the shizzle as far as pipe dopes go!

Ron The Plumber

We never use Rectorseal

fqp25

Regular old Teflon tape should not be used on gas piping. They do make a tape for gas pipe but it is more expensive than pipe dope.

Good old slic-tight pipe dope for me. but I know it's getting harder & harder find.

Ron The Plumber

We use Megaloc on gas pipe no tape

Teflon tape with pipe dope on brass fitting.

Teflon tape on plastic water fittings male thread adaptors

Megaloc or teflon tape on plastic male threaded drainage fittings.

majakdragon

I use teflon tape on most joints under 2" except gaslines. I don't even trust the yellow tape for gas. Over that size , pipe dope. I believe Rectorseal #5 is probably the best pipe dope compound around since I haven't seen Key Tite in quite a while. One thing about teflon tape though. Don't buy that $.39 junk stuff off the bargain bin shelf. I have seen some that was so thick, you couldn't even get it to stick to the threads.

mccoy

Which is best for transitioning from a threaded PVC to metal connection, teflon tape or plumbers thread compound?

Ron The Plumber

Teflon Tape if it's a water fitting, pipe dope if a drainage fitting.

Double A

Read the label. The label will tell you what you can use it on.

Rectorseal #5 is an oil solvent based product and will attack and weaken ABS plastics. Rectorseal T+2 is safe for ABS plastics as is Hercules Megaloc.

When using teflon tape, be careful with plastics. You can put too much on the male threads and when screwed into a plastic female fitting you can cause great pressure in the fitting and it will fail. Rule of thumb is, two wraps max. More is not better.

winkydink

I saw no one mention the liquid Teflon.
Yet I see many plumbers using it.
Not sure which they are using it on.

Also when (what type of connections) should have NO tape or dope or liquid Teflon ?

thanks

wink

Ron The Plumber

On compression joints, but sometime I will use pipe dope at the point of seal on a compression joint if it's brass. But it's not needed.

paulm

'Shizzle' is new to me, I don't know if that's good or bad...

I'm trying to seal against off-road diesel fuel. Before you say 'Diesel fuel is diesel fuel,' let me tell you that it is NOT. The dye in off-road diesel attacks a lot of thread dopes. Rectorseal tells me NOT to use #5, but rather to use #7. Other manufacturers say, "Diesel is diesel." Anybody have experience with plumbing for off-road diesel fuel?

Paul in WI