NPT OR NPTF threads for your high pressure fittings

[swamp diver]

Keep in mind that stainless and aluminum are not the best materials if you plan to do anything with oxygen or rich nitrox mixes. Brass is your friend in those cases (you'll alway want to be careful with sealing surfaces and any lubricants as well).

As Wookie stated it is very hard to find brass fittings rated above 3000 psi. All our nitrox and pure oxygen system are plumbed with stainless 316 tubing and fittings.

Lately we have purchased some difficult to find fittings SAE (ORB) to NPT elbows from Stainless Steel Fittings | Compression Tube Fittings | Stainless Adapters and received good service. The fittings were actually made in Ohio by Airway manufacturing and an identical copy of the Parker dimensions plus less than half the cost.

 

[Gunner52]

yea I've kind of noticed there isn't much brass above 3000-3500 so i'm going to be building my system with all stainless I want everything to be rated for 5000 since that's the max pressure my compressor will go to and I don't ever plan on running more than 30% thru my system. again probably over kill but id rather over do it than have an issue at some point.

thanks for all the info everyone's been a lot of help especially with some of the sources for parts that's been my biggest struggle so far is finding suppliers that aren't charging double or triple cause its scuba related.

 

[mathauck0814]

yea I've kind of noticed there isn't much brass above 3000-3500 so i'm going to be building my system with all stainless I want everything to be rated for 5000 since that's the max pressure my compressor will go to and I don't ever plan on running more than 30% thru my system. again probably over kill but id rather over do it than have an issue at some point.

thanks for all the info everyone's been a lot of help especially with some of the sources for parts that's been my biggest struggle so far is finding suppliers that aren't charging double or triple cause its scuba related.

EAN30 @ 5000psi in SS, fine. But otherwise, seriously, be reasonable - why on earth do you want oxygen at 5000psi? What's the application that justifies that? Use brass on low and mid pressure fittings, use stainless on your highest pressure fittings. Don't use stainless where you CAN get a brass piece if O2 goes through it. Nitrox is more like air than O2, so if that's your application by all means go with SS. I do a lot with high pressure O2 (3500psi) and have no problem getting brass for most of those fittings.