DIY Pressure Regulator For Exciting SCUBA

To get a SCUBA certification, a prospective diver will need to find a dive shop and take a class. Afterwards, some expensive rental equipment is in order. That is, unless you’re [biketool] who has found a way to build some of his own equipment. If you’re looking for a little bit of excitement on your next dive, this second stage regulator build might be just the thing for you.

It’s worth noting that [biketool] makes it explicitly clear that this shouldn’t be used on any living being just yet. The current test, though, was at 120 PSI using some soda bottles and some scrap bike parts. The OpenSCAD-designed regulator seems to work decently well for something that’s been homemade using some 3D-printed parts and other things available to most tinkerers/makers/hackers. [biketool] also goes over some issues with the regulator leaking and discusses porosity issues inherent in FDM printing but overall this project looks promising. Whether or not you want a pressurized 3D printed vessel that close to your face is rife for debate.

We don’t see a lot of SCUBA-related hacks around here. After all, it’s one thing to power an air horn with SCUBA tanks, but it’s a completely different thing to build something that keeps you from drowning.

Thanks to [dave] for the tip!

57 thoughts on “DIY Pressure Regulator For Exciting SCUBA

        1. Yes, DMHO is especially poisonous when inhaled. It’s quite benign when you just get it onto your stomach, but also via that route a lethal dose is possible. (Around 14-15l in a short time)

    1. No more dangerous than say trying to breathe freshly pumped air out of a bicycle tire. The only precision part under any stress is the Schrader valve which is not ever under any more stress than a bicycle tire.

      1. It’s a second-stage regulator; the input air pressure isn’t that high – it’d just blow itself out of your mouth.

        Which isn’t to say it isn’t insanely dangerous for all sorts of _other_ reasons.

      2. They don’t work like that. I’ve had a second stage regulator go on me under water. It wasn’t fun but it wasn’t too dangerous either. There’s a few things to note:
        1. When they go they release air into your mouth. You won’t explode, the air will just run past your lips.
        2. Diving training specifically covers what to do when this happens, the answer is to pull half of the regulator out of your mouth face head down and sip the air as it passes.
        3. Your biggest risk is a low tank. When the regulator lets go your air starts depleting continuously and quickly. You have some time to do it in a controlled fashion but it’s definitely time to find your partner and start the emergency procedures (be nice, don’t rip their regulator from their face)
        4. Fun fact, your teeth get really REALLY cold when you are breathing through a faulted regulator. This caught me by complete surprise during training.

  1. “We don’t see a lot of SCUBA-related hacks around here.”

    Maybe, that’s because you can’t really screw around with scuba gear, your life really depends on it.

    On the other hand, as the inventor stress that it shouldn’t be used on living people, it must be a very interesting project, just for the sake of it.

        1. Yeah, they invented the thing, carefully, baby steps after baby steps. And still, many of them died.
          Like Cousteau did with scuba diving, and if I recall well, he started with industrial respirator, not from scratch.

    1. People can make knives, some of those spear guns are like slingshots, I bet weight belts don’t require much safety testing, maybe making flippers works too. If you can find the material, someone is likely making their own wetsuit.
      Who wouldn’t want to make a diving sled or such? That sort of thing was likely described in Popular Science or Mechanics in the old days. I think they even described compressor, so you didn’t need a tank, just ä long hose (and obviously for diving close to the surface).

      Lots of peripheral things could be made, but yes I likely wouldn’t trust home made for the breathing system.


  2. For the non-divers. The first stage takes tank pressure from potentially thousands of PSI to around 100 psi relative to ambient pressure. This would be the dangerous stage since depending on the mode of failure it could send tank pressure down the low pressure side. The second stage is a demand valve and simple equalizes pressure between the air side of the diaphragm with the water side. If the schrader were to stick open excess air would flow out the exhaust ports, diver could still breath. If schrader failed to open the diver should fall back to their secondary air source.
    Neat project btw.

  3. These are revolutionary ideas to think about, but 3D printing just simply isn’t perfectly water tight. So it definitely won’t hold any amount of pressure. I printed a plant vase with 3 perimeters at 100um layers and the bitch still leaked water. I found tiny spots where water was weeping between layers. So as far as a pressure vessel, no way.

    1. Depends on how you finish the print. Acetone vapor smoothing for example fills all the little holes. There was a recent example that was being used (from memory) at 3 bar.

    1. Why? Do you think humans should cease tinkering and sharing dangerous information because someone may get hurt? How far do you think human advancement would get? Or let me guess you think that humans crawled out of the ocean, evolved into monkeys and then into us and at some point just discovered a pre-made dive regulator set presumably left here by aliens complete with safety warning and training so we could dive in the ocean?

      Go bubble wrap yourself.

  4. First stages have never failed or stuck… And depending on if you use yoke valves or DIN, you’re wither going to get a massive amount of pressure on your second stage, or a slightly more massive amount of pressure at your second stage. I would rather have a professional second stage in my face rather than this thing when that happens…. My main second stage is metal bodied, so it would likely survive other than the diaphragm. But I do have a plastic octo regulator I guess, but again, I’d trust it over 3d printed PLA any day!

    1. Yoke, DIN, plastic or metal. none of that matters. After the schrader the 2nd stage body does not see any significant pressure relative to the ambient. Not sure why yoke DIN was brought up as those have nothing to do with second stage regulation. For the record I use DIN on all my tanks LP, HP, and plan ol alu 80s and both my primary and secondary are plastic body. Oh and I also wouldn’t trust PLA either, not because i’m worried about it failing but because it would deform in the hot trunk of my car.

      1. Yes, I think PA-GF30 or PBT-GF is a better choice (glass fiber reinfordced nylon or polybutylenterephtalat). PBT is the stuff automotive ECU-connectors are made from, a very durable material.

  5. I don’t think it’s too dangerous when used in conjunction with a commercial regulator as back up. If the first stage fails, well, that’s bad luck with any equipment. As long as it’s just made out of plastic and has some sort of intentional break points… After that explosion emergency ascent is the only option anyway.

  6. Perhaps not for tank diving below 30 Meters. But how about a Hooka dive at 10 Meters. Where the main pressure is < 20PSI. Wouldn't that be more fun than snorkeling ?

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