Piston sliding room

Show us your pneumatic spud gun! Discuss pneumatic (compressed gas) powered potato guns and related accessories. Valve types, actuation, pipe, materials, fittings, compressors, safety, gas choices, and more.
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pat123
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Fri Dec 14, 2007 4:56 pm

I have been working on a piston for about a month now. I am almost finished all I need to know is how much room does the piston need to slide back, about and inch? i'll post pictures when it is finished.

thanks
Pat
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DYI
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Fri Dec 14, 2007 5:04 pm

For a coaxial, the piston should have a stroke roughly equal to 1/4 x barrel porting ID. For a barrel sealer, it can have a bit more travel than that, probably 1/2 barrel ID or so.
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pat123
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Fri Dec 14, 2007 5:07 pm

thanks this is my first piston. the port is 1.5 in so I'll make it 3/4inch
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MrCrowley
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Fri Dec 14, 2007 5:08 pm

Depends on the I.D of the barrel.

In a co-axial the piston should slide back 1/4 of the barrels diameter.

In a barrel sealer I would say the barrels diameter as a max slide back distance. So if you had a 40mm(1.5") barrel, I would say 40mm maximum and probably 20mm(3/4") minimum.

It doesn't really increase performance a lot in bigger bore guns as long as you keep the pilot volume to a minimum and have a decent pilot valve.


Damn, DYI beat me to it :(
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