Permatex56521 High Performance Thread Sealant ,Thread Lock & Screw Glue for Bolts Nuts & Fasteners to Prevent Loosening & Corrosion, Removable w/ Hand Tools 50 ml

I used this for the past few years on systems that use 300 PSI hot air and 250 PSI near cryogenic CO2; no leaks at all. It works far better than Teflon/PTFE tape or the more common thread sealants. I use the surface prep spray regardless of the material my fittings are made from. (successfully used on steel, stainless steel, brass, anodized aluminum, titanium)

In automotive work, thread sealant has become commonly needed and used on modern aluminum engines and transmissions, magnesium transfer cases and differentials, bolts that go through water jackets, and drain and fill plugs to prevent fluid leaks. These new metals cannot be tightened to the higher torque levels that were used when the components were iron or steel, and the thread sealer prevents leaks at lower torque levels. It should be used on the bolt or plug threads when doing service work on these components. So, that's why I bought and use it, There are many types of these sealants, but this product is specially designed for automotive components, and it works perfectly to prevent leaks, and to prevent bolt or plug seizing that damages threads.The price on Amazon is low, and this correct product is hard to find in my area. I am pleased with the purchase.

Worked well for my transmission lines. And my transmission pan bolts.

I use this for every metal to metal pipe fittings. Teflon tape is good but this thread sealant is much better and easier to use because it allows adjustment of the fittings to line up fittings which doesn't work when using Teflon tape. I make sure final adjustments are made within 1 hour as this sealant does cure in the absence of air in the close fitting metal to metal part of the joint and fully cures in 24 hours. If using on stainless steel or anodized aluminum or other inactive metals it's recommended that you use Permatex Surface Prep Activator to ensure proper cure. I was curious about using it on PVC, Permatex says it's NOT recommended for plastic fittings such as PVC. So I plumbed my shop with PVC and used teflon between the male PVC fittings and female metal fittings on all of my air drops and then use this Permatex 56521 sealant for everything else and it has worked without fail for more than 20 years. It's important if you use pvc to metal pipe be sure that the pvc fitting is the male and threaded into a female metal fitting. If you do it the other way around and use female pvc and thread male metal pipe into the pvc fitting it will expand the pvc over time and it will result in a leak. Just what I learned and hope it helps you out

Slathered a little on the threads after a good cleaning of threads then torqued it down inside the boot hole and cured without leaks .

Sealed up leaky fittings at the pump hat on an aftermarket Sniper EFI Tank. Vender recommended using Permatex Aviation Form-A-Gasket. Yeah, that didn't work. Bought this stuff and, boom! No more leaks.

I used this sealant on some brass air fittings on my two stage air compressor. I didn’t have much luck with the paste I bought from the local home improvement store, lots of nuisance leaks. I cleaned the old sealant off of the fittings, cleaned the threads with scotch brite, then isopropyl alcohol and a lint free rag, let dry, then applied the sealant. I let the assembled fittings cure for 24 hours, then pressurized to 175 psi. No leaks, not the slightest amount. I highly recommend this sealant!

I used thread sealants before so when I came across this Permatex product I ordered some. No surprise it worked a treat. paint it on (small artist brush) the threads as directed, wipe off the excess, done! Pressurized the fitting with max pressure. All Permatex coated fitting were checked for leaks. Three days later pressure in system has not dropped from original pressure. Took the roll of Teflon tape tossed it away.