Questions on a DIY project

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Something I forgot to add above. The only thing tank wise I think I need to buy is a high pressure gauge that I can waterproof myself, and the first and second stage regulators. Anything I am missing? Thanks.
 
I will have to machine an adaptor for the first stage but that will be easy.

You have my envy!

... I hope this is the first of many projects you get to enjoy and share with us.

Here's a thought from a guy with friends who use those little HP hand pumps for their paintball tanks. They are exhaustingly insufficient for their task. It's doable but the idea of filling a larger cylinder makes my joins hurt at the thought. I'd suggest looking into this aspect of your project a little more. Some calculations regarding pump barrel capacity and the number of pumps and energy requirements to fill the vessel you're building.

Regards,
Cameron

P. S. If someone would ask nicely enough, might you do small side jobs making adapters?
 
Trust me, you do NOT want one of the hand pumps for air guns. I have used one and it takes a long time to pump up an air gun, I can only imagine how long it would take to pump in any useful amount of air....and it's darn hard work.

I really don't think you quite grasp the equipment requirements of this project. Besides a tank and shutoff valve, you will need a first stage to reduce the high tank pressure to some lower usable/stable value, then a demand stage to supply air to you. That is a lot of fabrication and expense when you could easily find older used scuba equipment that will do the job for a much lower cost and effort. Even the tank pressure gauge is not worth the effort, it's much easier to find a used scuba one as opposed to trying to waterproof a standard gauge. Also, a scuba gauge can swivel so you can look at it, something not practical to do with a standard gauge.
Then there is the issue of the weight of your gear under water. If it floats, you will need to add weight and if it sinks, you will need to add floatation to get it neutral in the water. How do you intend to carry the gear, some kind of harness or backpack? Not trying to bust your bubble, just think you are missing a lot. I have done a good bit of this kind of thing. I have made regulator parts, compressor parts, adapters and done some significant modifications to dive regulators so I have some experience doing what you have in mind.
Taking into account cost, safety and operation of the equipment, your best bet is to find a used spare air, a scuba tank and a fill adapter for the spare air. These are designed to do what you want, if properly used are safe, will be less expensive in the long run and have resale value if you decide to not use them. And we have still not addressed the source of high pressure breathing air.

All that said, you still need to realize that even at a few feet deep, you can seriously hurt yourself breathing compressed air unless you follow some precautions. All in all, you would be best served by taking a scuba course and buying used scuba gear.
 
To answer your questions and adress you concerns, which are completely valid, I will clarify, as my above posts may not have stated it, that I will be purchasing a 1st and 2nd stage of the shelf. Everything else will be fabricated. I will look more into the used dive gauges as well. Tentatively planning to carry the "tank" in an old camelback carrier. Best thing off the top of my head until I get to that part of the project. How would I do the calculations for the hand pump stated above? I have previously tried to find some but I was unsuccessful. Thanks for the replies.
 
First thing is get certified even to dive in shallow water. You do know you can embolise yourself in as little as 5 ft of water. Then just get a pony bottle and cheap regulator to do what you are trying. Lots of other things to make besides what you are thinking about that has changed very little since it's invention by Cousteau and Gagnon.
 
I completely understand throwing time and money into a project just to say, "I did it". But given the risks involved, and how cheap used Scuba gear can be found, I'd hit Craigslist up for a used al80, bcd, and a used reg set. Tanks can be found for 50 to 100 on a regular basis, reg sets for about the same. I'm in Oklahoma, far away from anything I would consider good diving, and equipment is always on craigslist. There are several Facebook based Scuba related marketplace sites as well.

Scuba is not hard, but it's the details that will kill you. Trained divers die far too frequently due to equipment issues or simple lapses in judgement. I'm not opposed to diving solo, but Training and experience reduces the risk there as well. There are private instructors that will certify people far cheaper than the brick and mortar shops are charging. Once you have a C-card, getting air fills is a matter of walking into your local shop, assuming there is a shop close by.

The best part is an aluminum 80 should give even a new diver at least 45 minutes of dive time at 20 feet. Get the training, scrounge up or rent a set of used gear, and my guess is you will be hooked like the rest of us. Otherwise, you have an untrained diver, using home built gear, diving solo, in a river (currents, debris, low vis, and whatever else may apply) ...yea...not much could go wrong there.

Good luck,
Jay
 
5L = 0.0176573333607 ft³
Plus or minus a baby midget gnat's hiccup.

holy sigfigs.....
8db4e68ea9a631b5d9cf24a62c575b00595978ec89f6bdf036d252e3d9f90d01.jpg
 

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