3 inch piston valve cannon build.

[clemsonguy1125]

I like combinations of springs, foam, soft rubber, and tennis balls, you will need a large bumper on yours.

[LovableAirGuns]

Ill proberly be using a spring since im filling it from the chamber but ill also use a tennis ball cut in half mayby.

[Technician1002]

For a large washer, you will need to make your own. Find hardware stores that carry sheet neoprene and cut one with a hole saw on a drill press. Avoid big box stores as they don't carry what you need. Find a farm supply store or local hardware store.

[LovableAirGuns]

http://m.youtube.com/index?client=mv-go ... =4mhc09cf9
^
I was thinking about doing a piston like this |
Get rid of the m at the beginning if it dosent work the first time.
Edit: by the way im using my phone.

[Crna Legija]

getting rid of the m didn't work

[LovableAirGuns]

Look up on you tube: barrel sealing piston valve (part 1) : it should be some balled old guy, the first minute is shooting then he shows the internals and stuff.

[clemsonguy1125]

Yeah the one made of solid wood. The only thing with that is its extremly heavy.

[Gaderelguitarist]

It doesn't need to be solid wood. You could make washers out of wood and mount them on a bolt similar to how people make pistons with metal washers, nuts, and threaded rod.

[LovableAirGuns]

It doesn't need to be solid wood. You could make washers out of wood and mount them on a bolt similar to how people make pistons with metal washers, nuts, and threaded rod.

which is what i was thinking and then put it on a all thread rod

[mark.f]

Wood can be used, but make very certain to seal it with a lot of polyurethane or resin (thin the resin with acetone and apply in thin coats), so moisture doesn't change its dimensions and cause it to bind or come apart.

While you're at making wooden pistons, why not slap on a leather cup seal for one-way equalization. Should add a certain je ne sais quoi to your piston.

[Gaderelguitarist]

Mark makes a good point. It's also critical to factor in the thickness of the finish when you make the wooden piece as well. Another solution would be to saturate the piece with a water thin CA glue, then sand smooth. This will make it extremely hard as well as protect it from moisture without changing the dimensions of the piston.

[LovableAirGuns]

While you're at making wooden pistons, why not slap on a leather cup seal for one-way equalization. Should add a certain je ne sais quoi to your piston.

I know this might be a pretty stupid question but would mount it at the front of the piston? or does it mount some where else on the piston?

Another solution would be to saturate the piece with a water thin CA glue, then sand smooth. This will make it extremely hard as well as protect it from moisture without changing the dimensions of the piston.

The CA glue idea is great witch is what ill use when i get around to making the piston

cheers everyone on the help and a ideas

[Technician1002]

One comment on the piston seal. At 400 PSI in that diameter there will be tremendous force on the valve seat. If the seat is a narrow pipe edge, it will cut a smaller washer out of the larger one. Give consideration to make a wide valve seat so the rubber does not get sliced.