SpudFiles

I made a 1 inch piston but i can't vent it with a blowgun. I made a half inch piston to vent the 1 inch piston and the blowgun won't vent that either.
I don't have a nozzle on the blowgun and i made the hole on the piston in the blowgun bigger. I may drill out th einlet hole. is there any chance of messing up the blowgun by doing this? how much will this help.

If you can't pilot such a small piston with a blow gun, then something isn't right.

Can you put up pictures and details of your pistons and blow gun?

I am going to try it on my 2inch piston that i spent a little more time on first and see if that works. if it does i definitly need to make a better piston.

why not get a 1/4" ball valve to se if it is possible to vent?

For information regarding modding the blowgun, noname did a write-up on it in this thread

Some pics of your piston valves would be nice. The only thing I can think of is that your pistons are too loose. Finding a tighter fitting piston or adding an o-ring may solve your problem.

yeah a 1/4 inch ball valve will vent it. i think the problem is that it is in steel pipe with a seam and it can't slide very good with the seam in the pipe.

You could shove in another pipe (but this one is seamless) for the piston to travel in.
If the piston is too loose:
Try adding a few layers of duct tape around the piston, if that works, you should try to add an o-ring if possible. I dont know whether the seam will "be compatible" with the o-ring though.

i may mold a piston in the pipe that will have a slot for the seam.

You could always try to sand down the seam a bit. Is it very rough or is it a smooth seam?