Pipe Dope, Plumbers Putty, or Teflon Tape?

[JeffNC]

?

They are used for different purposes so you cannot lump them together. Dope and tape are to join pipes to fittings. Putty is to seal a "clamped" joint.

But you just did lump 2 of them together.

 

[JeffNC]

Here's my opinion. I'm not a licensed plumber, but I do a fair share with bathroom remodels and other light plumbing installation and repair, and I have a background in several sciences.

Clearly the putty is a different category, and you've figured that out by now.

The issue is dope vs. tape, and frankly most of the answers even by pro plumbers make no logical sense. If you think about what's happening with the materials, using them together is pointless.

Let's say you're one of those that uses both tape and dope. So first you put your tape on, then the dope. Well, what happens when you screw that joint together is that one side of the threads has only tape touching it (the tape basically keeps the dope from touching that side), and the other side has dope touching it. They can't both be best.

Both are lubricants. Both help seal the micro gaps in the joint to resist water leaks. But they can't both be best at that job - only one or the other are. Use only the one that is best. That one will touch both sides of the threaded joint.

Personally, I think the best lubricant and the best long term sealant is pipe dope. I use this on shower arms, threaded nipples, and female PEX adapters on threaded shower valves. On any connection where there is a compression or gasket seal, it only gets in the way and gunks things up (except maybe as mentioned by Jeff Young above - then a small amount is acting strictly as a lubricant). If those leak, there is a different problem, such as a little piece of debris, crack, misalignment or other issue that needs to be corrected first.

 

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[JeffNC]

[delete]

 

[DirtyJerz]

Based on some recent stuff I did my thinking is tape is going to be more helpful in closing bigger “gaps” because you can wrap it around multiple times to bulk up the male side of the pipe. Threading the female end on will at most “cut” into the tape and leave the bulk in place. With dope I feel like if you put on too much, the front end of the female pipe will just push it forward instead of filling in the gaps.

But maybe that doesn’t make any sense either. I agree that doing both seems unnecessary.

 

[JohnCT]

Here's my opinion. I'm not a licensed plumber, but I do a fair share with bathroom remodels and other light plumbing installation and repair, and I have a background in several sciences.

Clearly the putty is a different category, and you've figured that out by now.

The issue is dope vs. tape, and frankly most of the answers even by pro plumbers make no logical sense. If you think about what's happening with the materials, using them together is pointless.

Let's say you're one of those that uses both tape and dope. So first you put your tape on, then the dope. Well, what happens when you screw that joint together is that one side of the threads has only tape touching it (the tape basically keeps the dope from touching that side), and the other side has dope touching it. They can't both be best.

Both are lubricants. Both help seal the micro gaps in the joint to resist water leaks. But they can't both be best at that job - only one or the other are. Use only the one that is best. That one will touch both sides of the threaded joint.

Personally, I think the best lubricant and the best long term sealant is pipe dope. I use this on shower arms, threaded nipples, and female PEX adapters on threaded shower valves. On any connection where there is a compression or gasket seal, it only gets in the way and gunks things up (except maybe as mentioned by Jeff Young above - then a small amount is acting strictly as a lubricant). If those leak, there is a different problem, such as a little piece of debris, crack, misalignment or other issue that needs to be corrected first.

When I was installing my new oil tank, the instructions that came with the tank required that both teflon tape *and* pipe dope be used simultaneously. Seeing as how the firomatic valve had to face out from the tank on a 90 and there's no guarantee that the valve will face the correct direction when fully tightened, the dual method of sealing seems to make sense. One thing's for sure, you don't want to find out you have a leak at the bottom of an oil tank after you fill it.

John

 

[John Gayewski]

Based on some recent stuff I did my thinking is tape is going to be more helpful in closing bigger “gaps” because you can wrap it around multiple times to bulk up the male side of the pipe. Threading the female end on will at most “cut” into the tape and leave the bulk in place. With dope I feel like if you put on too much, the front end of the female pipe will just push it forward instead of filling in the gaps.

But maybe that doesn’t make any sense either. I agree that doing both seems unnecessary.

The dope helps the threads slide across the tape.