Best 45/37 flare fitting option for SUS304 to AL6061 connection

Hello everyone, i'm trying to find some more information on a project i'm working on but i'm still learning all the types of mechanics behind the task.

I have about 1000 (potentially a lot more) 1/2" OD x 0.035" SUS304 tubing ends that I need to connect to AL6061 manifold bodies and i'm wondering what the best connection method for this would be? The components will have normal atmospheric pressure air flowing through them with the occasional tap water flow to clean the system out.

With that said, what would be the simplest method for these connections that would still allow for the possibility to remove the tubing from the manifold for manifold maintenance? I originally used copper tubing with brass flare fittings, but that involved turning down a bunch of brass flare x MPT fittings because the current design of the manifold only has 6.5mm of thread depth available, and also we chose SUS304 for other purposes instead of copper.

Because the manifold body does not have much threading depth, I was thinking to have 45* flares/threads milled to the side of the manifolds, thus eliminating having to buy flare couplers, turning them down, and install them tightly in place. Then I was thinking to use regular cheap brass flare nuts. But something about that set up seems off.

I would really appreciate any input on this to get me in the right direction on what would be the best method for connecting the pipes to the manifolds, thanks!

I would use a Swagelok fitting with straight threads and an o-ring to seal to the manifold. Other end is a tube fitting to fit the tubing.

Erich, thanks for the suggestion. I avoided compression fitting connections from the start because I didn't want to have permanent connections with the brass crush ferrules. I had no idea that there's delrin ferrules and silicone rings for non permanent compression fitting style connections! This definitely seems like a viable solution. I will start looking into this.

At the same time though, I did like the simplicity of a flare connection. Something like this isn't easy to flare? However for JIC, I would still need the two sleeves anyways. Looks like 45* flare or compression would be the best thing, and 45* flare on this tubing isn't ideal.

I've done JIC flares on stainless tubing and it worked quite well. I think we were using either 1/4" or 3/8" and they were high-pressure grease lines. Don't cheap out on the flaring tool.

You said you only have 6.5mm of thread depth. Is it okay if the fitting protrudes beyond that? With very low pressure, thread strength shouldn't be an issue. If extra length is okay, I'd use standard BSPP or SAE-ORB x JIC fittings. Parker makes them. If not, I'd look at buying bonded seals and having a shop with a bar-fed lathe spit out short-straight-thread x JIC. Alternatively, you could shorten existing fittings. A shop with the right second-op lathe could make pretty quick work of it. Use a stepped hex collet and go to town.

AN/JIC oring fittings are pretty shallow if you can get the male fitting on the tubing end with a swivel that allows them to be removed.

Thank you everyone for the help and direction.

I ended up designing the compression fitting threads as part of my manifold, and then I used the o ring trick from the homebrew community. Worked out perfectly.

I ordered #110, #112, and nylon back and front ferrules and experimented with the different combinations. The best was to just get rid of the ferrules and use 2 o rings. The #112 has a 1/2" ID o ring and the body would make the nut a little harder to tighten by hand since the OD of the o ring was too similar to the ID of the nut. But the #110 o ring has an ID of 3/8" which when stretched on, allowed the compression nut to be tightened easily, as the body size shrinks due to the slight stretching.

O-Rings for a compression fitting | HomeBrewTalk.com - Beer, Wine, Mead, & Cider Brewing Discussion Community.
Compression Fitting with copper | HomeBrewTalk.com - Beer, Wine, Mead, & Cider Brewing Discussion Community.