What's the dope on pipe dope?

[Clog]

What is the dopist pipe dope?

TL forum searches for "favorite pipe thread sealant" and "best pipe thread sealant" yielded no results.

There is a such a plethora of products out there today. Up until now, I've mostly used Rectorseal #5 in the yellow tube, have tried Rectorseal T+2, and over the years have used other random "pipe dopes", such as Great White from Oatey, or whatever happened to be available or handy. I think the earliest thread sealant I ever used was the John Sunshine Mitee Dripless Pipe Joint Compound, which came in a yellow box and a yellow tube as well. That goes back several decades ago. It became a DAP Inc brand.

In recent years, many pipe thread sealants have emphasized the color blue, for some reason. Blue Monster, Blue Magic, Blue Block, Blue Megalock. Even Rectorseal got in on this blue colored pipe sealing act with their trademarked "Tru-Blu." Oatey re-enters the fray with their Great Blue Pipe Joint Compound. The industrial brand LA-CO checks in with their LeakTite Blue, not to mention Weld-On with their Blue Seal, and then Spears has their Blue 75, and even Northern offers a Premium Grade Blue. What's the deal with all this blue?

I don't care about color. I want a good, no, the very best pipe thread sealant for lubricating and sealing lead free brass fittings for use in potable hot water.

And I do mean sealant, not necessarily dope. Dope just made for a dope thread title. Sealant, on the other hand, can also include anaerobic resin compounds. I ran across an article called "Guidelines for Choosing a Pipe Thread Sealant" , edited by Joseph L. Foszcz, in Plant Engineering. Ignoring the portions describing teflon tape, I'd like to quote where he discusses the advantages and disadvantages between pipe dope and anaerobic resin compound sealants, which he clearly prefers over pipe dope:

PIPE DOPE:

Pipe dope relies on a solvent carrier and hardens when the solvent evaporates. The resulting seal adheres to all plastic and metal pipes and effectively blocks leak paths. Because it contains solvents, pipe dope has a tendency to shrink over time as the solvent dissipates. This condition creates the potential for the dope to pull away from the thread walls or crack, allowing leaks to develop.

Advantages: chemical composition is compatible with all pipe materials, including plastic. Pipe dopes harden quickly and produce a moderate to strong seal.

Disadvantages: Solvent-based pipe dopes can lose their effectiveness as the result of heat aging. When the seal shrinks and cracks, leaks can develop. This possibility is especially true with systems that are subjected to significant vibration. Pipe dopes may lack sufficient resistance to solvents.

Recommended Uses: Solvent-based pipe dopes provide an adequate seal in applications where high temperatures and pressures are NOT expected. Pipe dopes offer MINIMAL resistance against vibration. They are acceptable when the installation of a piping system does not require adjustment of components more than a few minutes after assembly.


ANAEROBIC RESIN COMPOUNDS

Anaerobic resin compounds use a different cure chemistry than solvent-based pipe dopes and do not contain solvents. The cure begins when the sealant is confined within the threads of the metal pipe connection and air is excluded. Without solvent content, the cured material does not shrink or crack, and maintains its sealing properties even after heat aging. Because of their chemistry, anaerobic resin compounds exhibit excellent temperature and solvent resistance.

Advantages: Anaerobic compounds fill the voids between pipe threads, creating a seal. The compounds cure slowly, providing additional time to make adjustments to pipe system components without damaging the seal. Once cured, the compounds form a strong seal that resists the effects of temperature, pressure, solvents, and vibration. Joints sealed with anaerobic resins can be taken apart with standard hand tools. Many anaerobic thread sealants contain Teflon or similar lubricants which aid assembly and reduce the potential for damage to pipe system components.

Disadvantages: Because of their chemical composition, compatibility of anaerobic resin compounds with plastic pipe and fittings should be verified before use. Although these compounds cure sufficiently for many immediate uses, a 24-hr period should be observed before activating high-pressure systems or allowing significant shock or vibration. Anaerobic resins can be difficult to remove from clothing or gloves.

Recommended Uses: This class of sealants provides the strongest, longest-lasting seal presently available. They are recommended for temperatures up to 300 F, pressures up to 10,000 psi, and where vibration will be encountered. These sealants are the choice when installers must make minor adjustments to a piping system.

So, what type of pipe thread sealant do you use on metal threaded pipe joints for potable hot water, steam, as well as for gas service applications? Your favorite, most reliable sealant. The kind you apply where you know that you will never be called back.

 

[Terry]

I've used a variety over the years and they pretty much all work. Lately I tried Megaloc, and before that Blue Monster. In the 70's Rectorseal 5 was used. Most of the time I'm picking up something with some Teflon or Kevlar in it. If in doubt, three wraps with tape and coat that with dope. Sometimes fewer wraps if using dope also. On gas I just use dope.

 

[Sponsor]

 

[Mike Reilly]

What is the dopist pipe dope?

TL forum searches for "favorite pipe thread sealant" and "best pipe thread sealant" yielded no results.

There is a such a plethora of products out there today. Up until now, I've mostly used Rectorseal #5 in the yellow tube, have tried Rectorseal T+2, and over the years have used other random "pipe dopes", such as Great White from Oatey, or whatever happened to be available or handy. I think the earliest thread sealant I ever used was the John Sunshine Mitee Dripless Pipe Joint Compound, which came in a yellow box and a yellow tube as well. That goes back several decades ago. It became a DAP Inc brand.

In recent years, many pipe thread sealants have emphasized the color blue, for some reason. Blue Monster, Blue Magic, Blue Block, Blue Megalock. Even Rectorseal got in on this blue colored pipe sealing act with their trademarked "Tru-Blu." Oatey re-enters the fray with their Great Blue Pipe Joint Compound. The industrial brand LA-CO checks in with their LeakTite Blue, not to mention Weld-On with their Blue Seal, and then Spears has their Blue 75, and even Northern offers a Premium Grade Blue. What's the deal with all this blue?

I don't care about color. I want a good, no, the very best pipe thread sealant for lubricating and sealing lead free brass fittings for use in potable hot water.

And I do mean sealant, not necessarily dope. Dope just made for a dope thread title. Sealant, on the other hand, can also include anaerobic resin compounds. I ran across an article called "Guidelines for Choosing a Pipe Thread Sealant" , edited by Joseph L. Foszcz, in Plant Engineering. Ignoring the portions describing teflon tape, I'd like to quote where he discusses the advantages and disadvantages between pipe dope and anaerobic resin compound sealants, which he clearly prefers over pipe dope:



So, what type of pipe thread sealant do you use on metal threaded pipe joints for potable hot water, steam, as well as for gas service applications? Your favorite, most reliable sealant. The kind you apply where you know that you will never be called back.

I was just humbled. Yesterday I installed a cast brass laundry sink faucet by Design House. It said to use teflon tape on all the metal threads. I said nuts to that and went to my trusted Harvey TFE paste, "Superior Quality" pipe thread compound. Even slathered it on heavily to take no chances [copper to brass]. So confident, I put 'everything' together, even put some tools away, before I turned the water on. The result was, both pipes had 2-3 pinholes each peeing water out right away. Yes, furious was I. Tightening more made no difference.
Fast forward, it seemed to take forever to clean every trace of the TFE from all the threads then dry them. Then I went round and round with the teflon tape and threw it back together; thinking it would leak even worse now. When I turned on the water, it did NOT leak one single drop and has not since. I've since decided it's better to do what the manufacturer wants. We don't always know everything we think we do at times {;-) Have a "Superior Sunday" & thanks for the great forum! Mike

 

[Jadnashua]

FWIW, with a few exceptions, the manufacturer's instructions tend to work best. They have a vested interest in their product working properly, long-term. Most quality ones actually test their products (a sample of many) versus the average homeowner that may be doing it for the first time. Plus, as products change, the advice from the manufacturers can change. Unfortunately, that also means the 'common knowledge' about what works may no longer be true.

Probably the worst advice is from someone that says "I've been doing that for years with no problems...why should I change?". Some things stay the same, but many more actually DO change. I know many people never read the instructions, but you don't know what you may be missing if you don't!

 

[hj]

For them to have that recommendation, they must NOT have had much confidence in their threading and tapping machines, (apparently with good reason). About the only time I use tape is for PVC threads. I once helped a plumber on a big gas project, He wanted to use tape and it was a disaster. We had to take most of the joints apart and redo them with dope/sealant or whatever you want to call it.

 

[Michael Young]

BLUE MONSTER!! both teflon tape and pipe dope.

 

[Mike Reilly]

One major thing I have noticed. MANY of these Chinese galvanized and copper fittings on the market now have very rough and crudely cut threads. It is a far cry from our USA made, smooth and well finished off threads we have been getting and expecting for so many years with our products. This could very well be related to this frustrating leak of mine.

 

[Michael Young]

One major thing I have noticed. MANY of these Chinese galvanized and copper fittings on the market now have very rough and crudely cut threads. It is a far cry from our USA made, smooth and well finished off threads we have been getting and expecting for so many years with our products. This could very well be related to this frustrating leak of mine.

if you're getting shit cuts from your plumbing supplier, make sure they know about it. My supplier switched to another vendor specifically because of poorly cut threads

 

[Sylvan]

HJ remember Quick wick and prodope ? Worked like a charm (not on gas) and Permatex on steam /heating applications