SpudFiles

specifically for a piston valve gun with actuation of a blow gun.
Is it better to bevel and round out inner parts and make all the part have better flow or leave as is for less air to pilot the piston valve

more flow = better.

There won't be a noticeable difference so I wouldn't go through the trouble...

It is generally accepted that modifying a blowgun by increasing the flow path will allow air to leave the pilot area faster. The actual impact on performance is pretty insignificant, unless your piston valve was honking or closing because the pilot wasn't being dumped fast enough.

i see , thanks all another flow question .... what is the optimal travel distance for a piston inside its housing?
more the better or is about 1cm to about an inch good enough ?

A piston should open far enough so the porting area opened is larger than the valve seat area.

Many use 1/4 the valve seat orifice as the minimum distance to be considered fully open as the gap between the piston and valve seat has the same cross sectional area.

I generally view this definition of open as two equal restrictions to flow in series. I prefer to open the piston a little further so the first restriction is negligible and the only significant flow restriction is the valve seat orifice. For this I prefer the piston to move at least 1/2 the valve seat diameter.

For example if you have a coaxial valve and the barrel valve seat has a diameter of 1 inch or a metric value such as 10mm, the minimum using the 1/4 diameter would be 1/4 inch or 2.5mm. Using a larger value of 1/2 the diameter would give 1/2 inch or 5mm for the above example seat diameters.

ah alright good explaining Tech, got it . i just came back from modding a blow gun i had.Im not too sure how much it held before (probably more than it does now) but now it only goes up to 80 to 100ish psi before it starts leaking ive taken it apart and made sure it put it in as airtight as possiblebut still no luck. Any tips and suggestions ?

How did you mod he blowgun to hold more pressure?

i didn't mod it for pressure , if thats even possible , i modded it for more flow to actuate a 1/2 inch piston valve.

Sorry lol I misread it

okay now update with the vid. pretty much self explanatory .

Major Collins wrote:okay now update with the vid. pretty much self explanatory .

Like this: [youtube]video url[/youtube]