SpudFiles

This is kinda a weird question but do you think that a paint ball tank would be suitable to use as a mini scuba tank?

Of course I would empty the high pressure CO2 out first and fill it with air and I would attach regulators to reduce around 150psi to breathing pressure. It is just for a small experiment, i wont dive deeper than 4m (i know the dangers of using normal air down deep) and I don't expect it to last longer than 3-4 minutes.

The only thing i am not sure about is rust. The tanks are made of aluminum so they should be good, but I'm not sure about the valves. Do you think this could work?

Try it. First just dunking your head in and taking a couple breaths, then timing to see how long it lasts, then using the information you get to use it for shallow diving or whatever.
I don't think the tanks rust, mine have got wet several times with no consequences, and I've had them for over 4 years.

Cool. I haven't actually got a tank yet, I was looking at buying one online but I am not quite sure which size will be best. I want one no bigger than a 1.5litre coke bottle either 9oz or 12oz.

Does anyone know how to safely empty a CO2 paint ball tank that has a pin valve without turning the tank into a sonic jet?

...deep?
You don't know what we mean by "deep", do you?

(nitrogen narcosis - essentialy getting drunk on air - doesn't begin until like 100 feet or so with normal air (I forget the exact number - but I'm only cleared for 60', so I shouldn't be going that deep anyways)...
Furthermore, us recreational divers generaly limit our dive times so that we don't require decompression cycles... and our [big] air tanks barely provide enough air for us to stay down that long. (again, without checking the literature))

That said, I figure a 20 oz container at 1000 psi would give you about 1 cubic foot of air - which should be good for a minute and a half. (plus-minus 30 seconds)

...if I remember the size of a 20 oz container correctly. Which I might not.

If you are looking to buy a tank it will come empty, so you wont need to empty it. I would get a 20oz tank... It is not that big.... If you are looking to get serious just spend the 50$ on ebay and get a 68ci 3000 psi tank. That will provide you with MUCH more air, also the insides of co2 tanks are kinda nasty... i wouldnt breath it.

boilingleadbath I should of mentioned this before but the air tank will have a trigger on it so that I can only get air when I press it down, it is not continuous like a scuba tank, it involves me holding my breath a little so that is why I don't want to dive too deep. I am not really planning on using it as a scuba tank, more of a snorkeling aid.

I used a 5 liter weed sprayer as a tank before and that lasted me 2minutes at 30psi so having a paint ball tank at 150 psi will last me about the same or more. The only downside of using a weed sprayer is that it is too big and too buoyant.

http://cgi.ebay.com/Spare-Air-2-Scuba-T ... dZViewItem


just get somthin like that off ebay. ive seen them cheaper then that i was just looking for one to use as an example...

i THINK you can refill them to

No thanks, I'm the kind of guy that would rather build something than buy it. But that is basically what I am trying to build. I usually go snorkeling off a kayak so when it runs out, i will just refill it using a hand pump. Thanks for everyones info.

Well the air might have a metallic taste. As for rust, the tanks tend to get cold when you play paintball and water condenses on it and Mine has never rusted. I can't imagine why it wouldn't work for what you're talking about.

Final question.

How big is a 9oz, 12oz and 20oz paint ball tank? I have searched all over the internet and can only find pictures but not dimensions. Or if someone could compare its size to a common object?

look for co2 tanks on eBay, the sellers will have the dimensions of the tank they are selling.

A 20 oz tank is about a foot tall, and about 4 inches wide. I'm just pulling these numbers out of my ass, but I can usually estimate things pretty well. A 9 oz tank is about 9-10 inches tall, and 2 or 2.5" wide. I only have those 2 sizes, so I can't give you a great estimate on the dimensions of a 12 oz.