Comments on: DIY SCUBA tank boost pump (for mixing gases)

By: fish tank

fish tank — Mon, 17 May 2010 02:00:27 +0000

Hello there, I found this website once, then lost it. Took me forever to come back and find it. I wanted to observe what comments you got. Nice blog by the way.

By: Krystyna Leibfried

Krystyna Leibfried — Sat, 08 May 2010 14:44:18 +0000

Need to develop the main subject a little be more.

By: jones

jones — Wed, 29 Apr 2009 15:26:29 +0000

Hello Owner.
Am MrJerry Jones. and i will like to make some special inquiries on some Scuba Tank or any Scuba Tankyou have . Below are some of the types Scuba Tank i will need.

Type Below
XS SCUBA Neutral Aluminum 80cf Tanks
Luxfer 40 cu. ft. scuba tanks
Al 40 ft Tank.
Al 80 ft Tank

Above listed are some of the Size of the Scuba Tank i will like to order. I will like you to get back to me with the pick up price of those Sizes Tanks which will include tax only. and also if you don’t have this types of the Scuba Tank and the sizes Then i will Advice you to email me the types of the Scuba Tank you have along with the sizes and the Price Or you can email me the Website of your Company .Also i will like to know the forms of payment you accept for your orders. Kindly advise and get back to me. I will be awaiting your feedback on this email.

Mr.MrJerry Jones
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By: Shabby

Shabby — Mon, 17 Dec 2007 14:56:49 +0000

Informated Article… Appreciated!

By: AdamS

AdamS — Thu, 06 Dec 2007 10:01:50 +0000

Chris… are you insane?!? Any tank or reg that is going to touch enriched air should be o2 cleaned per the manufacturer’s specifications at every service date (visualizes and hydros for tanks and rebuilds for regs.) Paying the extra $0.15 for the viton o-rings and $15 for the tank cleaning maybe over kill, but I’d rather do over kill then be killed. Take it from someone who has certs in full o2 deco diving and tri-mix blender, don’t do it. Home made fin straps, wrist slates, etc, are cool and not life support. Do you think the astronaut make their own gas pumps?

By: ynh

ynh — Thu, 06 Dec 2007 06:02:10 +0000

This project should not be used unless you REALLY know what you are doing. I not uncomfortable going to places that use something like this to boost o2. Professionally manufactured equipment with proper maintenance and with yearly gas testing is a different story. I would be willing to use this DIV project like this for non-volatile gases like helium for tri-mix or for argon for dry suit inflation, but o2+oil+heat is bad mojo.

By: Greg

Greg — Wed, 05 Dec 2007 03:09:34 +0000

Oh sweet merciful jesus this is dangerous. DO NOT BE DOING THIS UNLESS YOU’RE A CERTIFIED NITROX GAS BLENDER.

This is a great way to kill yourself — even from something as simple as opening a gas relief valve too fast (Avoid Quarter Turn Knobs — read into adiabatic compression.) Even using the wrong material for the gas lines can cause sparking or an explosion.

Editors should seriously think of pulling this down… if you’re not ticketed or licensed to do this, you can really screw up badly — blowing up your house, or at worst — getting yourself killed. And gibbed in the process.

By: Dave

Dave — Tue, 04 Dec 2007 23:57:33 +0000

All these Nancy woofters, Pooing desist. Due to various medical problems, I can’t get dive certified, so I have to free drive, buy rebreatehrs on ebay, and get ex military kit. So long as you are sensible, it is less risky than stopping in Miami for directions.

By: Greg

Greg — Mon, 03 Dec 2007 19:08:41 +0000

"greg- that pressure is only for storage. it goes through a series of regulators before the air hits the ball. the final pressure is on the order of 100 psi, dependent on the marker and settings."

I know, I used to play, the tanks have regulators on them and a lot of guys would add a second one especially if they had a low pressure marker.

By: pedro

pedro — Sat, 01 Dec 2007 23:24:02 +0000

joelanders, yes, thanks for correcting that. I added an extra 0 on the end, and did in fact mean 4.5k PSI.

for anyone who's interested, I use a 1.1 litre carbon fibre wrapped steel tank to store high pressure air at 4.5k PSI, which gets regulated down by my tank reg to 850 PSI. that then gets lowered to about 130 PSI by my inline regulator before going through a solenoid and bolt assembly.

it costs me like Â£1 to get my tank filled or free for when I'm at a field playing, but it would be nice to have a compressor to have infinite fills while at home training

By: Ed3

Ed3 — Sat, 01 Dec 2007 19:03:17 +0000

@srilyk: Mythbusters Special 8: JAWS Special – They did several JAWS movie related myths, including shooting a scuba tank to make it explode. They didn’t make a tank “explode” persay (eg. shear open), but they did find great ways to make a tank decompress in uncontrollable manners.

See also Episode 63: Air Cylinder Rocket where they made bulk gas cylinders fly through concrete block walls.

By: Chris

Chris — Sat, 01 Dec 2007 18:33:34 +0000

As an enriched air diver, there are a couple of misconceptions on this board – first, every NITROX diver is trained to analyze the mix after filling with a gauge – so by the time this guy straps the tank on, he knows what he’s breathing. Additionally, filling an empty tank with a certain pressure of 100% O2 and topping it up with compressed air (from a certified, clean SCUBA compresser) is a pretty accepted method for mixing enriched air – I know professional divers who roll their own helium mixes this way. The advantage to the method shown here is that your tank does not need to be ‘oxygen clean’ – you can still use rubber vs viton o-rings, etc.

By: mike

mike — Sat, 01 Dec 2007 13:50:17 +0000

Maybe DIY scuba isn’t the best example, but still, if getting the mixture right is that important then the only way to guarantee it is done right is to do what this guy is doing. It’s kind of the point of doing something yourself.

By: M4CGYV3R

M4CGYV3R — Sat, 01 Dec 2007 09:36:34 +0000

This is a great little mechanism for increasing force – I never would have thought a simple lever would be so effective.

To all those thinking “This is dangerous!” – that’s fine, don’t do it.

And to Pedro and anyone talking about Paintballing, this would be right on for filling an HPA or Nitrous tank @ about 3000 – 4000 PSI. I may have to try it out.

By: BrianB

BrianB — Sat, 01 Dec 2007 07:38:51 +0000

If you don't understand how a booster works then by all means don't even consider messing with any boosters (let alone a homemade design like mine). And if you don't understand Partial Pressure blending and the risks of high pressure gases then it goes double...

fentanyl3 has it right (thanks)

"just because it's homemade doesn't mean it's inherently unsafe, if you don't have the skills, then by all means don't attempt it"

"to add to that, it really make ABSOLUTELY no difference how dirty your working air is, or how much water vapor there is as it is completely isolated from the booster. If anyone disagrees please explain to me how contaminated air can escape one piston, travel through a solid steel bar, and permeate solid brass to contaminate your NOX tank?"

For the person who commented about Vance Harlows "Oxygen Hackers Cookbook" you might want to check out his "Improvised and Low Cost HP Boosters" airspeedpress.com. Guess what you will see in there? Yep, my booster...

As far as cost savings mixing recreational Nitrox there are none. This was a costly project which required a year of continual development. The reason to do it was my local dive shop went under and the closest place to get mix and deco bottles filled was 100-miles away. It has saved a lot of money topping off partially used Trimix fills. With a set of doubles filled with 16/45 (16%O2, 45%He, 39%N) running almost $100.00 plus two deco bottles 50/50 and 100%o2 running $30-$40each the booster has paid for itself. Please don't send me hate mail about 100%O2. Contrary to what most recreational agencies teach there is a place in Technical diving for it and other Voodoo Gas mixes we use.

In regards to the comment on the lack of an over pressure valve. If you do the math the shop air pressure multiplied by the ratios of the pistons and lever arm will only allow the supply gas to be boosted to a maximum of 3200psi (well within the range of all my tanks).

This booster has served me well for the past six years. Boosting O2 and He into hundreds of tanks then topping with air from my compressor (with homemade hyper filter stacks). I've dove these mixes to over 265' with deco obligations up to 100 minutes.

Would I build this again? No! It was much harder than I ever thought and there is still room for improvement (especially in the spool valve arrangement). If I had to start over I'd bite the bullet and buy a Haskell but then again I'd have missed out on a lot of learning and a great feeling of accomplishment.

There is nothing wrong with DIY scuba except you can't sue the manufacture :-) Heck I know people building DIY Rebreathers.

Play safe but always ask questions such as:

How does that work?

How could I build one of those?

Regards,
Brian B.

PS - I don't respond to flames but will answer questions as time permits.