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looking for critic

Post questions and info about pneumatic (compressed gas) powered cannons here. This includes discussion about valves, pipe types, compressors, alternate gas setups, and anything else relevant.
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looking for critic

Unread postAuthor: spudhead » Mon Jan 27, 2014 3:56 pm

this will be my first completed homemade air rifle. i think i will use a air chuck for a pilot valve for now. i am going to try to set it up as a hammer valve/qev. the air chuck doesnt look much different from a crosman valve so i dont see why it wouldnt work atleast reasonably well.

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Re: looking for critic

Unread postAuthor: jrrdw » Mon Jan 27, 2014 5:59 pm

I think you're leaving out some key details about this build because I just don't get/understand how this configuration will work...

It looks to me like the air will be dumped straight out the exhaust and the piston will just remain sealed against the barrel.

Am I missing something?
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Re: looking for critic

Unread postAuthor: jackssmirkingrevenge » Mon Jan 27, 2014 6:20 pm

jrrdw wrote:I think you're leaving out some key details about this build because I just don't get/understand how this configuration will work...


The hammer valve pilots the exhaust valve in the last photo.

Note that the QEV piston is a cup seal and if you fill from the chamber side it will never seal - you will need to poke a small (small!) pin hole in the edge.
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Re: looking for critic

Unread postAuthor: jrrdw » Mon Jan 27, 2014 10:42 pm

Oh jeez...I'm looking at this bass ackwards! Sheit there's even a arrow on the QEV L0L.
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Re: looking for critic

Unread postAuthor: spudhead » Tue Jan 28, 2014 12:52 am

jackssmirkingrevenge wrote:Note that the QEV piston is a cup seal and if you fill from the chamber side it will never seal - you will need to poke a small (small!) pin hole in the edge.


do you mean the initial fill from zero psi?

havent got that far yet. was thinking about drilling a air fitting for a rubber ball and pin, but i cant find any thing to fit inside the air fitting yet. as far as placement that would be further down the road. right now i am worried about how many psi the air chuck can hold up to.
actually due to the lack of volume that diaphragm gives when open. i have been thinking about adding a 1/2" nipple between the pilot and the qev. then replace that diaphragm with a piston like those made from a bolt, washers, and orings. the diaphragm is so thick it barely opens, but i think a steel washer with a rubber washer stacked would be thinner.
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Last edited by jrrdw on Tue Jan 28, 2014 10:30 am, edited 1 time in total.
Reason: Fixed quote.

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Re: looking for critic

Unread postAuthor: jackssmirkingrevenge » Wed Jan 29, 2014 5:38 am

spudhead wrote:do you mean the initial fill from zero psi?


Yes, unless you fill from the pilot side.
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