What's new

Pipe Tape Vs Pipe Dope

DiamondWash

Well-known member
Joined
Aug 31, 2007
Messages
1,897
Reaction score
65
Points
48
Location
Grimes, Iowa
I've been using Blue Monster thread tape for all of my threaded fittings and recently a plumber told me to always use pipe dope over tape it's just better all around he said, being I have had little to no issues with tape I wanted to get a second option from others on this subject, what do you prefer or recommend?.

 

DavidM

Member
Joined
Aug 31, 2007
Messages
399
Reaction score
12
Points
18
Location
PA
The only time I use tape and pipe dope is when the fitting still leaks after using just tape. This seems to happen occasionally on fittings 1.5" or larger. Otherwise I use only tape and have not had any issues. The pipe dope also tends to be annoyingly messy. It is up there with antiseize.

David
 

I.B. Washincars

Assistant Janitor
Joined
Aug 30, 2007
Messages
3,503
Reaction score
172
Points
63
Location
Circling the drain
I agree with David. I never have any issues unless it's the bigger fittings. I keep some dope in my truck. It comes in handy when a fitting is in a tough spot that's tough to maneuver a roll of tape around.
 

MEP001

Well-known member
Joined
Aug 30, 2007
Messages
11,317
Reaction score
282
Points
83
Location
Texas
I've got 18 months of professional plumbing experience under a master plumber. The rule is 1 1/2" and larger use tape with dope over it.
 
Joined
Jul 30, 2013
Messages
653
Reaction score
24
Points
18
Location
Central NC
100% agree. I do commercial plumbing & HVAC and I would never put tape on gas line piping a no no unless absolutely necessary I use regular white tape on the little brass fittings SS fittings little stuff. I have used MegaTape alot & big blue and don't like it on the little stuff because you can use too much in a hurry and seems like a mess threading it in just my personal prefference I have tried them all. The old school white tape still has its place on especially 1/8 spray tips all your 1/4 & 3/8 fittings I like the thick tape on fittings over a 1inch for me.
 

PaulLovesJamie

rural 5 bay SS
Joined
Aug 30, 2007
Messages
1,112
Reaction score
22
Points
38
Location
Kutztown PA
I was told a long long time ago that tape will prevent leaks in "small" pipes with low-ish pressure, and that is what most people use it for. But its primary purpose is to make it easier to separate the parts later for replacement/maintenance (especially if you have 2 different metals, galvanic welding and all that). Hence the TEFLON in "teflon tape." (yeah, he capitalized it when he told me too.) Dope is to seal the joint from leakage.
He also told me to use the right kind of tape - white for general purpose, yellow for gas, grey for stainless.

Perhaps confirmation bias, but that mostly matches my experience so maybe he was right.
 

Earl Weiss

Well-known member
Joined
Aug 31, 2007
Messages
5,196
Reaction score
74
Points
48
No issues with tape. Less mess. Then again rarely go to 1.5" or larger.
 

MEP001

Well-known member
Joined
Aug 30, 2007
Messages
11,317
Reaction score
282
Points
83
Location
Texas
I was told a long long time ago that tape will prevent leaks in "small" pipes with low-ish pressure, and that is what most people use it for. But its primary purpose is to make it easier to separate the parts later for replacement/maintenance (especially if you have 2 different metals, galvanic welding and all that). Hence the TEFLON in "teflon tape." (yeah, he capitalized it when he told me too.) Dope is to seal the joint from leakage.
He also told me to use the right kind of tape - white for general purpose, yellow for gas, grey for stainless.

Perhaps confirmation bias, but that mostly matches my experience so maybe he was right.
All correct from my experience and teaching. A properly-cut thread should seal with no tape or dope, but most aren't cut accurately, and dissimilar metals will not only rust/corrode together but threads should deform together to fill gaps which won't happen properly with brass into stainless or steel into PVC. Plus you have to tighten the living s**t out of a fitting for it to seal with no tape or dope, and I hate being on a ladder in cold weather trying to extract a broken street elbow out of the end of a boom.
 

JGinther

Zip-tie engineer
Joined
May 31, 2008
Messages
574
Reaction score
34
Points
28
Location
Loveland, CO
Main reason for using teflon tape is to reduce the friction between the two threads so that the threads will flex enough to form the water seal. The reason for using dope or sealant on larger fittings, is that most people aren't strong enough to get the seal with lubrication alone. The dope or sealant actually clogs the leak path along with reducing the friction. Tape with dope gives the benefit of both properties, as MEP explained.
 

buzzin

New member
Joined
Sep 3, 2015
Messages
5
Reaction score
0
Points
1
Location
america
1/4" - 1" = tape only
less than 1/4" = dope only (tape is awkward)
larger than 1" = tape + dope
pvc fittings = tape + dope and finger tight to prevent stress
anything that will be inconvenient to service gets tape + dope
 

Greg Pack

Wash Weenie
Joined
Sep 3, 2007
Messages
2,608
Reaction score
153
Points
63
Location
Hoover, Alabama
I found some 1" wide tape at zoro which I really like on large fittings (1"+)

After a plumber recommended it I started using permatex 80633 liquid thread sealant and have great luck with it. Its available at autozone and other fine retail establishments.

I use it on HP hose fittings too, simply because it makes it easier to break apart in the future.
 

MEP001

Well-known member
Joined
Aug 30, 2007
Messages
11,317
Reaction score
282
Points
83
Location
Texas
I found some 1" wide tape at zoro which I really like on large fittings (1"+)
I need to find some 1/4" wide tape. I fold the usual 1/2" tape in half for 1/8" fittings since I can't stand strings hanging off a part or tape on the nut/inside the fitting.

After a plumber recommended it I started using permatex 80633 liquid thread sealant and have great luck with it. Its available at autozone and other fine retail establishments.
I use regular blue LocTite when I have to assemble a lot of parts. It doesn't make things impossible to disassemble unless you really overtighten them. When assembling something like a manifold for the top of the boom I do tape the threads for the check valves and anything that will eventually have to get changed - it can actually make it easier later when you go to loosen the check valve and the fitting doesn't unscrew with it.
 

Jeff_L

Active member
Joined
Dec 27, 2007
Messages
1,239
Reaction score
23
Points
38
Location
Missouri
I agree with what everyone is saying, large fittings I use dope, small I use tape. I have never done both, but might try it sometime.

As for tape, I generally use the white stuff. I love blue monster, but it's expensive and I use too much too quickly. I use blue monster on fittings that I will most likely never have to take apart again, or at least for a very long time. Small fittings which you replace often, get the white tape treatment.
 

2Biz

Thread Killer!
Joined
Nov 22, 2010
Messages
2,269
Reaction score
26
Points
48
Location
Ohio
Everything above and this nugget....What I've been doing recently when I have to change out HP hoses is use JIC 37° fittings where I can. They are a compression style seat and don't require any sealant. You still may have threaded fittings that need sealed, but using JIC fittings where you can helps minimize leaks. Also taking the hose apart at a JIC union is much easier than at a threaded union. In some cases, JIC fittings also helps eliminate the need for swivel connections that are needed for tightening fittings.
 

br549ms

Member
Joined
Sep 23, 2016
Messages
147
Reaction score
12
Points
18
Location
Mississippi
Never use TAPE on hydraulic fittings, don't care what size or pressure you are talking about. if threads are NPT - use liquid Teflon or similar type of sealer. Same with most other piping, except pneumatic systems (the only thing I use tape on).

If the tape gets in your system it can cause major head aches, stopping up ports, checks, nozzles and injectors. "Dope" will just mix and flush through the system.

If you do use tape, make sure the tape does not cover the starter thread and cannot get in the flow path.
 
Top