SpudFiles

I've been thinking; wouldn't a deodorant can make an ideal chamber for a small air gun? Apart from a small volume, it has an in-built hammer valve, steel construction and built to handle pressure (albeit not massive amounts). Screw in a shrader valve to the back end, and your set.

One question though, why do they warn about the canister exploding when punctured, regardless of whether it is pressurized or not? If i was to use a drill press on a low-ish speed to make a hole for the shrader, would it be likely to explode?

I wouldn't.. The walls are extremely thin.

If it was empty it would not explode, but the material could tear easily. If you insist on using one please at least reinforce it.

Well it says on most cans, do not exceed temperatures of 50*C. Assuming that the propellant is entirely butane, then we can find its rating from the vapour pressure at 50*C, which is about 5 bar. This isn't very high, but I imagine it would go higher without saftey issues (7-8bar)

I might test it next time I get a spare can, although the possibility of shrapnel doesn not endear me to it.

Biopyro wrote:Well it says on most cans, do not exceed temperatures of 50*C. Assuming that the propellant is entirely butane, then we can find its rating from the vapour pressure at 50*C, which is about 5 bar. This isn't very high, but I imagine it would go higher without saftey issues (7-8bar)

I might test it next time I get a spare can, although the possibility of shrapnel doesn not endear me to it.

If you pressure test it, use proper containment and you will be fine. If it bursts at the same relative pressure as a 2 liter pop bottle, most of the flying parts can be contained with a simple metal trash can inverted over it with a proper sandbag on top to take the burst energy.

The safe way of course is to hydrostat test it. Fill it brim full of water and pressure test. The can contains very little potential energy for an explosive burst that way. It is the way I test some of my stuff.

rikukiakuchiki777 wrote:One question though, why do they warn about the canister exploding when punctured, regardless of whether it is pressurized or not? If i was to use a drill press on a low-ish speed to make a hole for the shrader, would it be likely to explode?

I don't think I've ever seen a notice saying the can might explode...

It's pressurised, possibly flammable stuff and they don't want you poking holes in the thing in case all subsequently goes pear shaped when some fruitcake inevitably does just that.

Things like surprising jets of gas and highly volatile liquid or even more surprising blasts of flame don't look good in court if you didn't paste a substantial warning on the can beforehand.

After all, if you were busy tinkering in your shed working by candlelight and you clamped up a new can of deodorant and got drilling away you wouldn't be a happy bunny unless you were a bunny that liked the smell of burnt fur and various degrees of burn.

the walls feel little thicker than soda cans i had one once and i could rip it apart using my hands

Ahem...

I think you'd better start looking for something else.

There are a couple reason for the warning against puncturing those cans. One is that the can still be pressurized and a ragged hole in the side may lead to a catastrophic failure of the can.

Another reason is that most cans are pressurized with butane, isobutane, propane, etc. Punch a steel tool through a steel can and you may create a spark. Use a power saw running at a couple thousand RPM and you will certainly create sparks.