question about valves

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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Tue May 05, 2020 3:13 am

hello everyone

i'm going through my first built of a spudgun, and i'm gathering the parts and doing research. I'm gonna use a 75mm barrel, but the valve i found is 1/2" in diameter. Will this difference in diameter impact my pressure/firing distance?
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jackssmirkingrevenge
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Thu May 14, 2020 4:47 am

You must think in terms of cross-sectional area.

In this case, 75mm is almost 6 times greater than 12.7mm, but in terms of area it is a whopping 35 times greater.

This is not a recipe for good performance.

The effects of the Square-cube law are quite pervasive in this hobby.

Finding a bigger valve commercially is going to cost you, so consider building your own or using something simple but effective like a burst disk.
Last edited by jackssmirkingrevenge on Tue May 19, 2020 3:42 am, edited 1 time in total.
hectmarr wrote:You have to make many weapons, because this field is long and short life
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farcticox1
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Mon May 18, 2020 5:48 pm

127mm or 12.7mm
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jackssmirkingrevenge
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Tue May 19, 2020 3:42 am

farcticox1 wrote:
Mon May 18, 2020 5:48 pm
127mm or 12.7mm
Good catch, edited.
hectmarr wrote:You have to make many weapons, because this field is long and short life
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