Pneumatic Cylinder/Piston Question

[SEAKING9006]

What sizes of PVC are available at Home Depot or Lowes that will fit well enough into each other to use them to make a pneumatic piston? I don't mean like your regular tee piston, i mean like a piston for a blow back/blow forward valve or for a general use telescopic cylinder. I want to make one for my next attempt at a cannon, which will use a crude blow forward.

[blind909]

1 inch sch 40 pvc fits perfectly inside of 1 1/4 inch sch 40 pvc.

[daxspudder]

1.5" nearly fits in 2", and with a little high grade electical tape will work perfect, as long as you make it so it "floats" in its space on its O-rings

[SEAKING9006]

Sweet. Now I'll be able to build my blow forward valve.

[SpudFarm]

when you say it a pneumatic press would be fun.

large surface area and 150psi would have crushed you.

[SEAKING9006]

when you say it a pneumatic press would be fun.

large surface area and 150psi would have crushed you.

Hmmm.... Sounds like fun.

[SpudFarm]

yepp.. but then you would need a 40" piston to get any real damage.

[SEAKING9006]

yepp.. but then you would need a 40" piston to get any real damage.

Or four 6" pistons on a sheet of steel......

[mark.f]

If you're looking for a good seal that will fit into pipe, do the obvious thing and use a test plug. They are used to seal off drain pipe and fittings to do leak tests and can be expanded and contracted by use of a wing nut. Further, you can use a standoff on the end of the threaded rod through the center of the plug to attach more threaded rod for a piston arm.

I don't see how you're going to achieve a double-acting cylinder, though, as you still need to seal the piston arm from the cylinder. Single-acting is easily achievable though (with maybe a few minor leaks).