another piston question

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kydavies
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Thu May 27, 2010 10:08 pm

im about to build my first coaxial piston valve and i was wondering if it is ok to have a small leak in the seal between the pilot and chamber (the piston will seal perfectly to the barrel). i know this will hamper the opening time of the piston but will it work if the piston isnt perfect
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piston2.png
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mikemurph wrote:yea, the ammo has been changed to a more aero dynamic projectile. it consists of the back half of a dart, and a hot glue ball
AHahahahah!!
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Lockednloaded
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Thu May 27, 2010 10:41 pm

it has been said that the piston need to be snug enough not to fall out or turn, and loose enough to be able to push with one finger
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Crna Legija
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Thu May 27, 2010 10:42 pm

if the gap is 1/2mm that to much
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Technician1002
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Thu May 27, 2010 11:59 pm

If it rattles sideways the gap is too big. A proper piston will look like it would stick if given a chance. This pipe was sanded smooth and then the piston was very carefully machined down until it just fit inside. It worked like a charm until the chamber developed a leak at the other end.
This cannon is now retired.
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The Mouse Musket breech. 2 inch chamber, 1 inch coaxial barrel, 1.25 inch valve seat (sealing surface) and 1.5 inch piston.
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Musket 30 PSI.mp3.zip
Mouse Musket testfire at 30 PSI.
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kydavies
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Fri May 28, 2010 7:28 pm

k thanks il keep that in mind when i get around to building my piston
mikemurph wrote:yea, the ammo has been changed to a more aero dynamic projectile. it consists of the back half of a dart, and a hot glue ball
AHahahahah!!
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clemsonguy1125
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Fri May 28, 2010 7:32 pm

Another trick is that if you shine a light through the barrel you shouldnt be able to see it from the back of the piston
That is all.
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