SpudFiles

Thanks for that, we most likely will be launching pvc or metal rockets, and to my post above the one about distance, not speed, any ideas?

-_- wrote:ive been looking for one of the bigger size fire extingsher to power my soon to come semi. at the maket i allways see 10L stainless steel LPG tanks, do you think they could hold 350psi.

In the USA, the working pressure (rated pressure) is 260 PSI. Refillable tanks that are designed to be transported full on US highways (DOT regulation) has a minimum burst pressure of 4X the working pressure. I do not know other countries safety regulations.

For fire safety, the safety relief valve is supposed to remain sealed at pressures below 300 PSI so they don't leak in hot weather.

Technically 350PSI is overpressure for a BBQ tank, but under the minimum burst pressure. I do not know the ratings for one time use tanks such as torch and lantern tanks. It's a pretty safe bet that a new one would hold 350 PSI, but they are not designed for anything but Propane. Moisture in the air may cause rusting on the inside.

At below the working pressure, the tanks even when shot with a high power rifle round only get a hole, but not blow up. At higher pressure, they may rupture violently when shot.

i take my propane tank up to 350psi but i coated theinside with paint to prevent rust from moisture. it is a LOT of air in that tank...

That is below the minimum burst pressure, but above the nominal (rated) pressure for that tank. If the tank fails at that pressure (gunshot, rust, dent, accident, etc) it may fail violently. It should not burst from just pressure.

Do you think that are any ways to keep the original fittings on the dive tank, because one of the reasons we choose a Scuba tank is the easy and cheap refillability

yes there are ways to keep the original vavle on the tank so can you get it filled. you just have to find the right adaptor to go to npt threads

Much thanks to all. I might add more once i start building it.

the one i always see is stainless steel so it cant rust.

You should look at investing in one of these adapters.

http://www.palmer-pursuit.com/cart/inde ... cts_id=225

It looks as though it is a yoke valve adapter and has a pressure adjuster and gauge on the side which means you could have both the reg and adapter in one. Connected to that you could hook up a hose with a ball valve to fill your gun as you said and read of the pressure gauge. You should drop them and e-mail and ask some details.