RE: sealing NPT threads, is there research tape vs. The paste does the rest and helps the joint resist vibration and thermal cycling. The tape provides full coverage to the male threads which helps resist galling in stainless parts if the fitter gets a little too aggressive with the pipewrench. We use heavy (at least 1.1 s.g.) tape with an anaerobic paste as a top dressing. It has other disadvantages including the mess factor- the affectionate name the fitters have for it is "bird sh*t". These pastes have nowhere nearly the corrosion resistance or other properties of teflon- and most of them contain far more other stuff than they do teflon particles. People should STOP calling it "liquid teflon" or "teflon paste", because that's a terrible description for what an anaerobic paste is. garbage tape and pipe threads cut with dull tooling, it's a TERRIBLE sealant!Īnaerobic paste alone is far more idiot-resistant, provided you select the right paste for the service. With Chinese 150# stainless fittings, Home Depot 0.25 s.g. With machined threads, the right tape and a skilled fitter, tape alone can give high reliability joints. It's also susceptible to leakage after repeated thermal cycling because it has limited "memory". Tape alone is too dependent on the skill of the pipefitter in applying it, the quality of the threads and other factors. Just like everybody else here, all I can give you is our own experience: Unfortunately, due to the lack of data and standards that we're discussing here, the method gets a VERY bad rap from a great many people. With a good sealant system, for the right services, threaded pipe can be a very reliable, flexible, inexpensive and useful method. I always wished I could have published the results internally before purchasing "helped", but once their decision was made it was final and publishing became counter productive.ĭavid RE: sealing NPT threads, is there research tape vs. I know there are any number of other options for field assembly of NPT threads, but I picked the three that were used most often in this area. Made me think that the teflon paste was overkill as long as the crew was able to properly wrap teflon and any sealant applied with the proper torque would work approximately equally as well. the tape and paste was indeterminate since both had zero leaks. The third crew did marginally worse with the Coppercoat, but the tape vs. One crew had multiple leaks at every location with every sealant. The preliminary look showed that one crew had zero leaks with any of the sealants. I was assembling the data when Purchasing weighed in with 200 cases of Coppercoat and wouldn't buy anything else. I did a comparative study 12 years ago (had three different crews each use tape on one location, tape and teflon paste on the next, and Coppercoat on the third, then repeat on 70 locations total-all locations had a similar number of fittings of similar size).
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