SpudFiles

Ok, I have a very small budget and I am extremely cheap. I wanted to see if I could make a pneumatic out of things I have laying around the house. Here is my idear, I have a 1L Dr. Pepper bottle, this is going to be the chamber, the schraeder valve would go in the bottom of the bottle where the plastic is thicker. Then I would attach some kind of barrel to the bottle cap. Then put a piece of shopping bag or trash bag over the opening of the bottle, screw the cap with attached barrel over the piece of bag, and use a bike pump to pump until the material gives way. Is there any chance of this working? I don't want to make this, and then go outside to test it and have something explode and lose my hearing or something. I saw somewhere that 2 L bursting pressures were near 200 PSI, so I figured 1 L would be stronger and I would only need to go to 90 or so PSI. Thought I would run it by here in case I missed something major which is likely.

I guess it would work, I would do some testing on the burst pressure of the bag first. And I pressure tested a dr. pepper bottle one day when I was bored, I got it to 110 psi without a burst.

I have done this on a smaller scale, and plastic bags have an unpredictable burst preasure. And even if you could get it uniform, it wouldn't be higher than say 15PSI. Because realy, dose it take more than say 30 pounds of force to put your finger though a grocery bag?

Try using tin foil in layers. It might rip or tear though when treading it on.

If you test the pressure rating of the bottle, make sure you fill it with water before you pressurising it. As much wather as possible. The pressurise it. If it "explodes", the bottle will only crack open since water doesn't get pressed together that easy. Do it with air, and it will realy explode, I've seen it happen (and heared it, almost deaf)