That Permatex 56521 says it's only good to 1000 PSI. Maybe they left off a zero?
I have used Aviation Permatex on pipe threads for years if I was working with fuel or oil. My recent third function project almost whooped me on pipe thread leaks. I finally chased all the threads with a USA made tap and die I bought at ACE Hardware and used some Blue Monster 76009 thread sealant. So far so good on that. I DID tighten the fittings as tight as I could get them but I had already done that on my second attempt using the Permatex. Chasing the threads on the furrin fittings. some bottomed out tight and some took a half to full turn past bottom.
I thought those Stuuchi couplers were supposed to be top quality but my grapple came with that brand but in a ball type ag coupler. The ball had rust pits in it and the installer hadn't capped them to keep dirt out. That last part isn't a reflection on the brand. I was replacing them anyways so it didn't matter.
Nah nah nah--I got the tip for that stuff from you guys, it's
good to 10,000 PSI (after 24 hours curing), and impervious to hydraulic fluid, oil, gas, baked bean farts, water, freon, xenon, krypton, plutonium--this stuff resists everything, especially when trying to wash it off your hands.
I don't know about Blue Monster goop or
Purple Dinasaur poop, never seen that in the wild, but WHO KNOWS??? (I don't eat
Kashi granola bars either, so there's that...)
I bought Faster & Stucchi after researching the snot out of couplers, another manufacturer makes a
safer coupler, but Faster are
supposed to be the most durable...I don't know, they do have a locking function so they can't come apart and they seem
really solid.
The ones I bought are steel, brass won't take the pressure and stainless is 2x the price, and my inherited AG and Pioneer couplers are steel and held up pretty good all this time--but they do like to leak hydraulic fluid whereas the Flat Face do not, so I don't know on that, maybe I should spray them with WD40 (got it in a
SureShot--great for oiling stuff down). Yah, I'm going to do that.