SpudFiles

150 psi isn't that low of a pressure. It is plenty to make a failing pipe a bomb and it should be respected.

I know you will be buying that Catalina cylinder but if you decide to go back to HPA but still feel the tanks are too big/heavy, check out: http://www.wevopaintball.com/3000psitanks.html

A question though: Just how critical is weight in your application? Is it worth going out of your way to find something that might make the gun a pound or so lighter? The average paintball gun isn't exactly the lightest and people manage. And are you sure that having to pump the gun every once in a while isn't going to put you at a disadvantage in the middle of a game? Remote lines aren't that impractical. They've been used in woodsball for ages.

Well, based on the numbers you gave, I concluded that you'd be looking at around 2 lbs using SCH 40 PVC.

More than your 1lb goal for sure, but still half the weight of that HPA tank. This is also assuming you get all 125 cubic inches of volume.

@PVC Arsenal:

Thanks for the link. I'm liking those tanks and they're making me reconsider the aluminum cylinder I was looking at.

The cylinder I'm going for weighs about half a pound. That's 3.5 pounds taken off, which is very substantial.

Weight's not mission critical, but it's something I want to reduce.

I'm more interested in Nerf than paintball at the moment. I shouldn't have mentioned paintball because in my experience you need a high capacity tank unless you're playing stock class.

In most Nerf wars, most people are using either spring guns, which are cocked every shot, or pump guns, which need to be pumped every shot. If I can get 20 shots off without recharging, I'm at a huge advantage already. And given that barely anyone (I'm probably one of less than 10) people in Nerf even have HPA or CO2 tanks, the weight of the guns can make a difference.

Oddly, this is coming from a guy who's done a lot of stuff with water guns and those guns can easily weigh 20 pounds. It's all relative I suppose, and I find this point mildly amusing.

In a Nerf setting I think weight and being able to refill during the game is important, at least for the moment. Maybe I'll hate the lack of capacity once I get the tank.

@TurboSuper:

12 inches of 3 inch pipe has a capacity of 85 cubic inches, the same as the aluminum tank I'm interested in.

Here's the breakdown of the weight:

Pipe: 1.41 pounds (linear density from here)
Caps: 2*0.464 pounds = 0.928 pounds (weight from here)

Total weight: 2.34 pounds

A 125 cubic inch tank as you described would weigh about 3 pounds with the same weights and densities.

The aluminum tank I'm interested in weighs about 0.5 pounds for comparison. Given the differences in capacity and the difference in weight between HPA and PVC, I'd rather use the HPA tank. But given a similar capacity but very low weight aluminum tank I'd take the aluminum tank.

Well, according to that PDF, a 3" cap is 0.47 lbs...

Anywho, if you don't mind the extra weight and have an HPA tank available then it sounds like a good plan to me. Aluminium would be great, but it seems like alot of trouble.

You are correct. I was looking at schedule 80. I've revised the original post.

Aluminum isn't a lot of trouble. Maybe my raving is confusing (I wouldn't be surprised if it was). The aluminum tank I'm considering costs $17.50 from the company I previously mentioned. The threads on the tank seem compatible with 3/4 inch NPT threads. Pretty simple.