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Jaxom · Senior Member

My Discovery arrived today!!! Wooohoo!!! Anxious to put a few pellets through it, I tore at the box like a child would on Christmas morning. I Quickly put the pump together (Oddtodd had to take the base and handle off in order to pack it.). Then connected my new baby to the pump....

OY!!! am I ever out of shape!!! Panting and puffing, I manage to get the pressure up to 1000 psi. Well, now I have even more reasons to loose weight, and quit smoking!

In the meantime...I wanna shoot!!! Did a quick search on scuba joints in my area. Low and behold, I've a place five mintues from home! To refill a tank it seems rather cheap. From $5 to $8 per fill depending on tank size and there's a break of you buy a 20 fill card for a flat $85.

First and foremost, what size scuba tank is recommended for using with ag's? I do realize the larger the tank, the more fills you'll get. There's a bit of a cost issue for size, I would assume. The shop I would be going to has tanks displayed, what's some average prices for a few different sized tanks. That will give me an idea of he's pricey or not.

Now, about refilling issues. Let's say I quit smoking and drop all the weight I want. That's still not gonna fix an issue I can see right away with the manual pump. That sure is one heck of a short hose! Does someone sell a longer one?

Speaking of which, I took a look at the scuba k-valve to discovery adapter. The hose looks rather short on that as well. A review on Pyramid Air.com of the adapter also mentions that it would be nice if they added a hose after the adapter so it won't scratch your ag. Is putting a high pressure hose here even possible? If so, again...who sells them?

Now this last question may seem odd, but here it goes anyways. How would you go about filling a smaller tank from a large scuba tank?

Here's why I ask. As soon as I financially can afford to do so, I plan on buy some hunting property (10-40 acers). I can use it for hunting as well as camping and even set up an ag range on said property. Obviously I would pack along my filled scuba tank and fill adpater. But lets say I'm out away from camp and I run low on air. I don't wanna trudge all the way back to camp to refill again, I'd want to fill right there on the spot. Would be nice if I could take along a smaller, back pack sized tank, that I could get a fill or two out of before heading back to camp. But I'd have to either fill from my main scuba tank or have the shop fill it for me, or bite the bullet and eventually get a compressor and fill it there. Which would you advise?

Tanks!

Jax

kanyon · Silver Status Member

A new 80cf tanks about 500NZ here...300US ?
The shorter/smaller the hose the less air you
lose when yer bleed down...
I have a hose for decanting from bottle to bottle
for welding gasses...But every time you do
you get a pressure drop and lose air/gas....

rsterne · Moderator

Don't bother with the older steel 72 cu.ft. tanks as they are only 2250 psi.... I just got an 80 cu.ft. aluminum 3000 psi.... you should get an initial 2000 psi fill on the Disco and about 80 refills (from 1000 psi) on one fill of the 80 cu.ft. bottle.... Cool

One word of caution.... because the SCUBA tank does not have a regulated output, you can easily overfill your Disco.... I would think 3000 psi would completely lock the valve.... whether it's dangerous or not will depend on how much Crosman over-engineered it.... Shocked

The best and safest way to fill is to get a smaller 3000 psi tank (48-62 cu.in) with the output regulated to 2000 psi and use that to fill your Disco.... Note that the small tanks are rated by the volume inside, multiply by 200 (and divide by 1728) to find the cu.ft. rating at 3000 psi.... ie a 48 cu.in. tank works out to 5.6 cu.ft. at 3000 psi and a 62 cu.in. tank works out to 7.2 cu.ft.....

Here is a tank fill calculator (a Disco tube holds 135 cc) :

http://www.airhog.com/tank.htm

If you fill a 62 cu.in. tank from a full 80 cu.ft. SCUBA at 3000 psi, both tanks will end up at about 2850 psi.... That will refill your Disco about 7 times.... Each time the small tank drops to 2000 psi, you top it up from the SCUBA tank.... and each time you get a little less pressure.... but it will still fill the Disco to 2000 until the SCUBA tank drops to 2000 psi.... Each time you will get fewer fills of the Disco, but the total number of fills should still be about 70.... When you get your second 80 cu.ft. SCUBA fill, you should get back to about 80 Disco fills per tank....

I know this method will waste a bit of air.... but on the other hand, it's safer (less chance of overfilling the Disco).... and you have the added benefit of a portable tank to take into the field with you.... Cool

Bob

Jaxom · Senior Member

Concidering that I'm on a budget, wouldn't it be best I start out getting the smaller tank first? The one regulated to 2000psi? That way I can get into sighting in a scope, practicing, ect. Then later on buy a larger tank to fill the smaller tank with.

That was also part of my question. Assuming both tanks were to have K valves...what bits and pices would I need for a tank to tank fill?

rsterne · Moderator

The smaller tank with regulator will have an ASA fitting, the same as paintball CO2 tanks, as the outlet of the regulator.... On the inlet (high pressure) side they are usually a male Foster fiting.... a K Valve is just too massive and heavy for a portable tank, I've never seen one.... the small tanks are usually either filled at a paintball station, or from an "Airgun Fill Station" which is a clamp that fits on a K valve equipped with a gauge, female Foster, and a bleed valve (to get rid of the high pressure air remaining in the clamp and gauge after filling the small tank)....

You're pretty much going to have to get a small tank filled at a paintball shop (the one nearest us charges $7.00 a fill).... I can get an 80 cu.ft. SCUBA tank filled for $10.00 (12 times the air!).... Rolling Eyes

Bob

Jaxom · Senior Member

but...I still don't know what bits I would need to do a tank to tank refill.....

rsterne · Moderator

http://www.jdsairman.com/MiscProducts.html

Top item is to fill guns from a CO2 or HPA regulated tank....

2nd item is to fill guns or HPA regulated tanks from SCUBA....

check eBay for better prices.... Wink

Bob

Jaxom · Senior Member

Thanks! Now I understand! <phew>

Edit: Found the second one at a good price, but not the first one... Sad/Cry

Also found a 48ci 3000psi tank for a good price as well.

rsterne · Moderator

Jaxom · Senior Member

Yeah, I wrote the vender asking about that. It's that or I would have to get the tank from either pyramid or jdair...then I know for sure they're regulated for 2000psi.

rsterne · Moderator

or PM AirgunEric.... Wink

Bob

Jaxom · Senior Member

Hmmm...the plot thickens...

Teryx · Veteran Member

Where can you get the parts to have an adjustable pressure fill set-up? I'm considering a Marauder that can be filled up to 3000, but most likely I'll find a good starting pressure much lower. Once I do, I'd like to be able to set up my fill station and get the same initial fill pressure every time.

Teryx

rsterne · Moderator

Adjustable regulators:

http://www.airhog.com/regulators.htm

Hope you've got DEEP pockets.... Shocked

Bob

sniper · Silver Status Member

my used 80 cf steel tank from mac-1 was $175 used with a current hydro. Shocked

with yoke adapter.