This was only one piston of more than 5 that I made out of hot glue. I had one you needed 30 sec. to pressurize with. Also other materials didn't work on the solid piston setup. I also made a solid piston with a build in check valve. They all didn't work with a blow gun.

When you look at the first diagram you can see the way the pressure goes with a solid piston (red arrows). The air push against the side of the piston. The other design has the advantage of a little more surface (piston surface -minus- sealing face) and a straight orientation in one direction. http:...

Even when the surface is bigger than the sealing face? The diameter of the piston is 21mm and the O.D. of the barrel is 20mm, so you need pretty much negative pressure on a solid piston to actuate. If you have a "piston on a stick" the pressure is not only on the sealing face but also on the surface...

Okaaaayyy, I said let's burry this topic but on second thought I had a plausible idea why the two pistons behave so different. When you use a barrel sealing, solid piston in a tee it doesn't benefit from the pressure in the chamber. http://img58.imageshack.us/img58/5937/solidpistonscheme.jpg When yo...

B.t.B., maybe your right, let's burry this topic. The piston design is good, now I can start to finish something.

to #1: how i mentioned in the video, I already used different materials on solid pistons, all results were the same.

#2: that's one more theory to think about. Thanks for the comment.

The piston and the hose barb that I'm using meet in the middle of the tee and both pistons have exactly the same length.

I always use ball bearing grease before I insert the piston.

This piston design doesn't work on my pneumatic. The piston is in a 3/4" tee, sealing a hose barb. This piston looks good for a coax.

When the pressure between the washers is equalized on a pressurized gun and you open the pilot, isn't it possible that the gaps give an advantage when the piston is pulled into the direction of the lowest resistance?

I'm going to reassemble my gun and film a comparison.

I tested both pistons on the same setup with very different results. Hot glue piston doesn't move with blow gun pilot. Metal piston does. Hot glue piston works fine with ball valve. Metal piston works "great" with ball valve. Is it a real good design for pistons, just a coincidence or does hot glue ...

Of course you are right. When I said "one day I had the idea" I meant a really long time ago when I was dumber about this subject (reading educates :wink:). The metal piston is actually heavier than the hot glue piston and the fit is compareable. Hypothesis: The hot glue part at the end has a bigger...

Well, I am new at this forum but I visit this side for quite a while on the search for new ideas and designs. I read a lot about piston valves and the importance of surface in this issue. So one day I asked myself; if surface is so important than why not providing surface to a piston? In the beginni...

What I meant with basic stuff is that there are so many great projects on this side that I will make a post on a gun that is really showable. Besides my gun is progressing all the time. Redesigning, adding parts, removing parts.... (damn I love threaded parts). At the moment it's put into pieces, ma...

Glad I was able to help. It took quite a while for me to understand the principle (by just watching schemes) of a piston valve and to find an easy way to take it into practice.

The reason why I never posted it on spudfiles is because I think it's still pretty basic stuff.