making my own distribution block.....

[TNRonin]

I would like to make my own distribution block for a sidemount doubles system. I wonder if there would be any issue with using 316L steel instead of that expensive marine grade brass. What wall thickness would be the thinnest? What do you all think?


ETA: I just found a company that does aluminum manifolds that are rated to 1000PSI and only around $20.
ETA2: I've found the manifolds in multiple configurations on McMaster Carr.

[Camerone]

316L will work just fine. You're dealing with IP here if you're on the low side of the regulator - which is only around 135 PSI (give or take a little.) Wall thickness will depend on several factors. Primarily, given that you've spec'd material, how big a hole are you drilling on the inside to line up your ports? Once you decide how big you want for gas flow, it's pretty straightforward to run the calculations for the pressure vessel and decide your wall thickness...but you're currently one-degree-of-freedom underspecified, at least with the assumptions of intermediate pressure and 316L that I've made.

While I'm all about DIY, have you considered these two: Silent Diving Direct or Silent Diving Direct? The larger (and strangely, cheaper) one is two split halves in a single block, as the oxygen and diluent both split out in the manifold.

Alternatively, I've used this piece - Golem Gear, Inc. - Y Block - 3 ports before and found it to more than meet my needs. Golem Gear / Jakub is a great guy to deal with and they have other similar manifolds which may fit your needs.

As much as I will encourage you to build this, the cost of buying one pre-made for the appropriate threads is just so inexpensive that it seems like more trouble than it's worth when you take into account having to do a couple set ups on the lathe and mill, the annoyance of tapping and deburring the holes, finishing it, degreasing / O2 cleaning it, etc. I know my time is worth far more than the couple of hours it'd take me to whip this out in the shop, and while I enjoy it tremendously, there's more complicated things to build that are probably a better use of my / your time.

[TNRonin]

Cameron I agree looking on McMaster Carr I'm seeing them dirt cheap and in the correct threading as well. I wonder if I can use aluminum? I'm still not there, I need to source the QC-6 fittings. I just can't see spending $200 on four fittings, I'm sorry.

[Camerone]

You can use aluminum, but I would recommend against it. First, you're going to have a dissimilar metal corrosion issue with the screw in fittings you use, which will cause them to either lock together, or weaken the joint over the long term. We see this all the time on stage bottles (which is we insulate the hose clamp, which is steel, from the bottle, which is aluminum...)

Second, aluminum just doesn't hold threads very well, which is something that always concerns me in a pressure-bearing scenario. The rule of thumb is you need around 3x more threads to hold in aluminum than you do in steel, and you've got no control over the mating parts length. Let's just say that I've had to turn a few replacement bits for the bottom of my Coltri compressor filter (aluminum) because I've over-torqued the mounting bolt, forgetting what it's going into...

-C

[TNRonin]

Thanks for the thoughtful feedback. looks like it is brass. LOL

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