View Full Version : Pipe dope or thread tape??


gsport
07-29-2008, 06:54 PM
what's the best to use on a compressor and air lines, regulators, etc??

ron in sc
07-29-2008, 07:02 PM
Rectorseal T plus 2

see link:
http://www.rectorseal2.com/files/213/dstplus2.htm

Nealcrenshaw
07-29-2008, 07:14 PM
Both. Wrap it a couple times then apply a medium amount of pipe dope. It will not leak!

ddawg16
07-29-2008, 09:37 PM
Compressed air? I think Teflon would be better...but a lot really depends on what material your lines are made of.

Here is a good thread on the subject Tape or Dope? (http://www.diychatroom.com/showthread.php?t=3726)

One of the things you have to understand about using tape or dope is that one of the purposes is to lubercate the threads so that the two pieces will turn easier....with NPT threads, this allows you to get a tighter connection which what is really sealing the connection.

We we do stainless steel fittings we use an anti-sieze compound....otherwise, the thread gaul up on you and it leaks all over the place.....not to mention the fact that you will never get it apart.

jimvannoy
07-29-2008, 09:41 PM
I always use tape on air lines and fittings. Never had any leaks. On water and gas lines I always use Rectorseal dope.

ImportTuner
07-29-2008, 09:59 PM
I always use teflon tape on air fittings; pipe dope on gas pipes and water lines ... probably wouldn't hurt to use both ...

Jared
07-29-2008, 10:05 PM
I use permatex thread sealant. always works for me, i cant stand teflon tape.

wantedabiggergarage
07-29-2008, 10:34 PM
At the shop, we used pipe dope on the hard lines, and tape on the end fittings. (end of hose and hard lines as they fail/get gunked up and need replacement)


At home, just tape, since my air hose is there, but no pipe yet (no place to run it). I am waiting for my brother to finish the barn, to do it correctly.

e-tek
07-29-2008, 10:40 PM
TAPE, TAPE, TAPE for me. I used pipe-dope once - on my Hydraulic lines for my lift....one is STILL leaking!

gsport
07-29-2008, 11:12 PM
thanks dawg... but i couldn't get the link to work
and thanks everyone else. i had used dope on all my hard lines but i still have a very small leak, think i'm going to redo em all again, this time using only tape.... wish me luck, jim

nissan_crawler
07-30-2008, 02:36 AM
I usually use pipe dope. When doing hydraulics, most manufacturers void warranty if you use teflon tape, that's why we used pipe dope on our farm equipment.

wantedabiggergarage
07-30-2008, 08:23 AM
thanks dawg... but i couldn't get the link to work
and thanks everyone else. i had used dope on all my hard lines but i still have a very small leak, think i'm going to redo em all again, this time using only tape.... wish me luck, jim

Make sure you check the pipe itself. My parents bought a new (for them) home, and we kept smelling gas in the basement by the furnace. We found that a section of pipe that lead to the water heater, had a hole, in between the threads. (pipe cut too deep?) The home inspector had to duck under it to check out the furnace and water heater, and still missed it.

Could be the connection, or the pipe itself.

RobRace10
07-30-2008, 11:13 AM
I just did mine with pipe dope last weekend and ended up taking half of it apart and putting tape on it because of the leaks. I would use tape and maybe add some dope. I wire brushed all the threads before I installed to make sure they were clean.

NSXSOON
07-30-2008, 12:11 PM
I use the thick yellow Teflon tape that is made for gas connections. Great stuff. Lowes and HD have it.

Nealcrenshaw
07-30-2008, 04:40 PM
Both. Wrap it a couple times then apply a medium amount of pipe dope. It will not leak!

It will not leak!!

larry4406
07-30-2008, 06:25 PM
Rectorseal, rectorseal, rectorseal. Teflon tape not needed.

Nealcrenshaw
07-30-2008, 06:46 PM
I'm from the old school. What's Rectorseal?

ron in sc
07-30-2008, 07:18 PM
Rectorseal, rectorseal, rectorseal. Teflon tape not needed.

I'm really suprised people are using all those other products when a product like Rectorseal T plus 2 is available.

I'm from the old school. What's Rectorseal?
Read link in post number 2

tatra
07-30-2008, 07:28 PM
buddy of mine is a pipe fitter and claims the purpose of teflon and dope is to lubricate the threads to allow a tight seal...............any pipe fitters who could comment on this?...........i have also heard some sites suggest using tape or dope on flare fittings for same reason...................my training was it was not needed.............course when you put only two new tires on a vehicle, they used to go on the front, now since ford explorers rollover debacle, they are to go on the rear..............go figure..................

fourfeathers
07-30-2008, 07:45 PM
When using dope, should you wait for it to dry?

i use both at times, I used to use the yellow gas line tape, but am using Permatex or the stick from loctite more lately.

jimvannoy
07-30-2008, 07:59 PM
When using dope, should you wait for it to dry?

i use both at times, I used to use the yellow gas line tape, but am using Permatex or the stick from loctite more lately.

I use Rectorseal and I never let it dry. Brush it on and screw the parts together.

Project-Z
07-30-2008, 08:15 PM
I learned a long time ago from a jouneyman pipe fitter that if you don't want leaks to tape the joint with a few wraps of teflon tape, and then use pipe thread sealant. I have been doing this in the course of my job and in my personal projects, thousands of joints later, and still no leaks.

One of the worst things to try and seal is ethylene or propylene glycol piping systems for heating, cooling or process applications. The method described above will guarantee no leaks!

I alway use Gimme the Green Stuff thread sealant from Jomar. It is usually available from plumbing wholesalers.

http://www.jomar.com/products/ThreadSealant.html

ddawg16
07-30-2008, 09:46 PM
One important point to remember when considering whether to use tape or dope is the threads and material.....

It is a total waste of time and dope/tape to use it on compression type fittings such as hydraulic....the only purpose of the threads is to pull the two hyd lines together...it's the flare, ferel, or o-seal that is actually doing the sealing....it it leaks past that point...the threads are going to do nothing for you.

And as I and some else noted...the real purpose of tape or dope is to lubercate the threads so you can get enough insertion of the male fitting into the female fitting. Notice that NPT pipe threads are tapered....you won't see NPT threads on hyd fittings.

pmiranda
07-31-2008, 09:21 AM
course when you put only two new tires on a vehicle, they used to go on the front, now since ford explorers rollover debacle, they are to go on the rear..............go figure..................

They've always supposed to go on the back... you want your best tires on the back, because if a tire is going to lose traction, you want it to be a front tire so the car will just slide straight instead of have the back end try to pass the front end.

I've gotta get me a tube of that rectorseal...good thread! I've never messed with iron pipe before, but I'm definitely gonna use it for my shop air in this new (to me) house.

garfunkle24
07-31-2008, 10:02 AM
Notice that NPT pipe threads are tapered....you won't see NPT threads on hyd fittings.

Actually you will, all over the world, on all kinds of equipment.

Also to Nissan Crawler, I am an ag mechanic and have never heard of warranty issues from use of teflon tape. I'm not disputing it's true, just wondering which manafacturers you've heard have a problem with this?

Torque1st
09-14-2008, 03:48 AM
For iron pipe fittings on compressed air lines use pipe dope if you don't have any Loctite 545 sealer.

Some of the import fittings do not have the best threads or thread forms. Many are over or undersized. Two turns of good Teflon tape will help those fittings seal against compressed air.

Brass taper thread fittings on pneumatic systems are real easy to split if Teflon tape is used on them. Watch your tightening torque. I like to use Red Loctite 545 Hydraulic/Pneumatic Sealant on brass taper thread fittings. It can also be used on iron pipe threads. It is a little harder to find than pipe dope tho...

All Teflon tape is not created equal. The cheapo stuff in the home box stores etc is no good.

Teflon tape should never be used on hydraulic systems.

The Rectorseal T plus 2 material has filler and fiber in it so it should never be used on hydraulic systems.

For Hydraulic systems use the red 545 Loctite or Loctite PST 567.

Many of the major hydraulic component manufacturers will void warranties if Teflon tape is used. Vickers and Rexroth are two.

Loctite 567 is good for stainless steel fittings.

Straight thread fittings like compression, flare, or O-Ring fittings do not seal on the threads. For severe environments use the Loctite 567 on the threads to help disassembly and protect the threads. Never use Teflon tape on straight thread fittings.

BigChevy80
09-14-2008, 12:01 PM
It's more a matter of personal choice I think. I've used nothing but the cheapo Teflon tape on all my water pipe fittings in the past. Only time I've ever had problems with leaks is from accidentally over-tightening them. I use copper line and solder most everything, so the only threaded joints I usually have to use are the two unions on the water heater and the two washing machine supply valves. Everything else gets soldered. On gas fittings I usually use pipe dope.

...just my 2 cents worth.

akdiesel
09-14-2008, 02:18 PM
Compressed air? I think Teflon would be better...but a lot really depends on what material your lines are made of.

Here is a good thread on the subject Tape or Dope? (http://www.diychatroom.com/showthread.php?t=3726)

One of the things you have to understand about using tape or dope is that one of the purposes is to lubercate the threads so that the two pieces will turn easier....with NPT threads, this allows you to get a tighter connection which what is really sealing the connection.

We we do stainless steel fittings we use an anti-sieze compound....otherwise, the thread gaul up on you and it leaks all over the place.....not to mention the fact that you will never get it apart.


We use the stuff called Silver Goop by Swagelok. It has silver to help lubricate as mentioned.