Which is better?

[Plinkalot]

A compressor or a scuba tank?

I can get a new 80 cuft scuba tank for around $300, a used one that's certified for around $200. A fill will cost less than $20 at a scuba shop, and I'd get the cleanest air possible.

80 cuft = 2,265,348 cc.

My gun has a 580 cc tank so I could get about 3,900 fills for about $320 total investment from an 80 cuft bottle. A smaller bottle would be lighter and more portable and still give plenty of fills.

Am I missing something here? It seems like this is an obvious choice to fill PCP gun tanks.

 

[WoodWelder]

Have you looked at this yet?

Airgun Tank Fill Calculator

 

[Plinkalot]

Have you looked at this yet?

Airgun Tank Fill Calculator

Thanks for that. I hadn't seen it.

If my calculations are correct, I can get roughly 1,170,000 rounds out of one scuba tank based on 300 rounds per tank. It would probably be more rounds because you fill a PCP tank before it's empty and it wouldn't consume 580 cc every time. I don't know if I'll ever fire that many rounds in the time I have left on earth. So why pay more for a fiber tank - your situation may differ.

Do you use a tank to fill? How big a scuba/fiber tank do you use, how big is your gun tank, and how many fills do you get out of a full scuba/fiber tank?

Thanks again

 

[BrazosbyNemo]

I think you are missing something or I am. Assuming you are talking about a normal scuba tank you can only fill it to a little over 3000psi. It won’t take long before that tank is well below 3000 psi. That means you can’t fill your rifle to 3000psi and won’t get as many shots. Once the tank is below 2000psi it’s done and you need to refill (really 2400-2500psi). With a carbon fiber tank you are starting at 4500psi. You can get a lot more fills before you drop down to below 3000psi. From your post I get the impression you think you can run the tank down to zero. You can’t. At some point your rifle will have more psi than your tank. At some point your rifle will fill the tank when it has more psi than the tank.

 

[wildcj5]

I prefer the clean dry air. I have taken apart a few used guns that had been hand pumped or filled with the pcp compressors. They were pretty nasty inside.

I have four scuba tanks two of the 3,000 psi and two of the 3,300. The 3,300 tanks are heavy. I also have one carbon fiber 4,500 psi tank.

I will start with one of the scuba tanks and as it gets lower in pressure I will still use it to fill a rifle and than use another of the tanks to top up to the 3k. So basically cascade them. With four this gives me lots of fills.

The down side is they are heavy and have the visual and hydro inspections. For me it works, I already had the tanks well before the carbon tanks became a popular option in the hobby.

When I first started I only had one tank and it was not fun. I was always at the scuba shop getting it topped up.

The other question would be where are you planning on getting it filled? The scuba shop by me fills on the spot while you wait. But I know some shops only fill tanks on certain days or after the shop has closed for the night.

If you go the carbon route with a 4,500 fill make sure the local scuba will fill it that high. Their normal fills are 3,000-3,300 and most don’t like running the compressor up to 4.500. Paintball and airsoft shops will do the full 4,500.

What state are you in? I ask because my local shop here is SoCal is going out of business and selling his used tanks with fresh inspection for $100 each.

 

[WorriedMan]

4500psi firefighter's SCBA tank and a compressor, able to fill it, are very popular. Yong Heng and GX-CS4 are good mid-priced compressors but multi-thousand-dollar units also get the job done. Smaller, gun-fill-only compressors, are least expensive, recommend avoiding tri-power rectangular box, high-speed fan only cooled ones. WM

 

[WoodWelder]

Did this get sorted out now?

 

[JimD]

I don't think the OP gave us enough information to provide a real answer. If he is thinking of a 3000 psi scuba tank it would not fully fill any of my guns except my Prod. 580cc storage seems like it will want more like 3600 psi which it won't do. I made up some numbers and used the calculator to come up with about 10 gun fills from a 80 cubic foot 4500 psi tank filling a gun with a 580cc bottle from 2500 to 3600psi. My tank is smaller but my guns are too and I get about 10 full fills to 250 bar plus some partials so it seems like the right ballpark. It definitely is not thousands or even hundreds of fills.

 

[Plinkalot]

Thanks for all the replies, forgot some and learned a lot about scuba tanks vs carbon fiber.

If you have a carbon fiber tank, how do fill it? Do you have your own compressor? Do you take it somewhere to get filled?

Thanks again.

 

[Airmanator]

A compressor or a scuba tank?

I can get a new 80 cuft scuba tank for around $300, a used one that's certified for around $200. A fill will cost less than $20 at a scuba shop, and I'd get the cleanest air possible.

80 cuft = 2,265,348 cc.

My gun has a 580 cc tank so I could get about 3,900 fills for about $320 total investment from an 80 cuft bottle. A smaller bottle would be lighter and more portable and still give plenty of fills.

Am I missing something here? It seems like this is an obvious choice to fill PCP gun tanks.

3900 fills from a 80cu ft on a 580cc bottle? What planet are you from cause I wish I got that many refill lmao. Most you get is about 7 refills. Not 3900 fills.

 

[WorriedMan]

Thanks for all the replies, forgot some and learned a lot about scuba tanks vs carbon fiber.

If you have a carbon fiber tank, how do fill it? Do you have your own compressor? Do you take it somewhere to get filled?

Thanks again.

Carbon fiber tanks need to be within lifetime and 5-year test limits for outside vendors to fill. Mid-price compressors, capable of filling CF tanks, Yong Heng and GX-CS4 come to mind, provide "air freedom" from these requirements. More expensive compressors also fill tanks, but cheaper, gun-only-fill ones, die quickly doing so. WM

 

[airman_o]

I have both: a compressor with a 9l tank. I'm happy with this choice, however it was quite costly. At first I also considered getting a tank and having it filled at a scuba shop. However after calculating a bit I realized I'd be at the scuba shop twice a week, and that's not very convenient.
The thing is indeed you can only use a rather small part of the tank before you need to refill it. I typically top up when I'm around 240 bar. Unless you want to shoot tethered, in that case you can basically shoot as long as your tank pressure is above your regulator. But shooting tethered is not that convenient either.