SpudFiles

I have been brainstorming to try to find a way to make my BBMG more portable, so I drew up a basic sketch of a possible solution. It uses a small (used and empty) fire extingusher that is safe to fill to 300psi. The idea for the regulator and gauging setup is similar to that of a standard air compressor. The only problem I am having is what to do about filling it. I think it is a solid idea, and the approx. 85 sq inch volume should be enough, due to the pressure that the tank can withstand. The regulator would be preset to 40-50psi. Tell me if you think it is even worth it. I also need suggestions for a filling mechanism.

add a Tee between the tank and the regulator and insert a bikevalve there.This should solve your inflating problem.

Theoretically what about a used (empty) propane canister? They can take really high pressure, too. Also, if you set it up for propane canisters, you could change them out quickly in the field.
The Tee Brian suggested should fix the filling problem unless the fire extinguisher (or other tank) has a one-way valve of some sort, which I doubt. I'd consider adding a pop-off valve somewhere, to prevent overpressure and to make emptying the tank easy.

Just suggestions. I'm thinking about building one of these this summer, and I was wondering how to free it from the air compressor hose. Thanks for the idea.

Peace,
Pete Zaria.

Im pretty sure that propane is only 90 psi but im sure you could link them up at only 70 psi because they are cheaper to come across. Also about the fire extinguisher tank are you sure that the top threads are npt (standard pipe threads).

just tap the it with 1/4 or 1/8 pipe threds, but make sure you do it in a thik part or it might explode or something.

its actually illegal to refill propane tanks yourself.

i dont think that even a tank of that size would keep a BBMG going very long. i'd just get/make a good air compressor and buy a big air tank at a flea market or something.

whoa! i just read my propane tank, if you refil it you get a $500,000 fine and five years imprisonment.

Wait a sec... isn't it illegal only if you refill it with propane? I don't see why refilling with plain ol' air would be dangerous, therefore illegal.

For 2$ more I can get a fire extinguisher, which has slightly more volume and there isn’t any penalty. Although the chances of getting caught for refilling propane cylinders will only be found if the item is seized in the event of use in a illegal action.

You should think though why did they make this law, and that is because there is a possibility of explosion. My cylinder reads:

"5. Never refill this cylinder. Refilling may cause explosion. Federal law forbids transportation if refilled- penalty up to $500,00 and 5 years imprisonment. (49 U.S.C. 5124)"

So unless you transport your cylinder there is in no way you violated the law, but seeing as they only hold ~90 psi because that’s when propane liquidizes at room temperature. Just use a fire extinguisher because they obviously have a sturdier construction which will prevent the possibility of a failure.

Even when charged to 300psi, that tank won't last you long.

What I do for my guns is attach a 20oz CO2 tank to a ~2 gallon expansion chamber (with a low pressure regulator in between, of course!) at 125 psi. Then use a second reg ($20 at Home Depot) at 80psi to the BBMG. Using some 3/4" PVC and strapping material from ACE hardware, I rigged up a backpack. It works great.

This May I'll be using it in some airsoft games

dont use it in airsoft, you dont know what the FPS is, and it could do some major damage to someone.

airsoft would be a bad idea. use a large propane tank from a grill. they are rated to 200 psi and have 3/4 inch ntp connection on the top for the valve