Well guys I got it working. I changed the diaphrams around with the plates..... and added a thicker diaphragm...

BOOM !! It went off and scared the hell out of me !
Been a week now and it wont fire - the barrel is not sealing so I am assuming the piston bent.... Im going to re-design it.

But at ...

Freefall

Good observation...... however - I already tried swapping the plate and gasket.... even tried greasin it.

I put a new one on without using the steel plate in front. It was very wierd, the valve went off (sprinkler) vent most of air (all but about 15 pounds) then it slowly hissed out the ...

I can put my mouth on the air inlet ( I know yuk) and push the piston closed with my lungs and suck it back till it seals with my lungs....

so is this design I have not likely to work ?? Is the CU IN of air PUSHING it towards the pipe to great for the push/pull force to pop the piston open ???

I ...

Here is a pic of the new trigger / dump- AND the pressure gauge I installed to be positive it was charging and it was not over charged

IT STILL DOESNT WORK.....and now it dumps pretty fast but still not 'instant'

I put a 1/2" tap into it, added the rainbird....

STILL no go......... I guess I ...

QUESTION

How tight is the piston / diaphram supposed to be anyway ? I mean is it supposed to be really tight ? you can slide mine with light finger pressure - its not loose but not tight either....

I said it dumps in 1.5 seconds... more like 3 seconds or so.

I removed the lil blower and put a sprinkler valve on it to dump the air so the piston slams back.... now it dumps in about 1 to 1-2/2 seconds.... By the way its attached to the back of the piston chamber via a 1/4" brass threaded ...

Here is my gun and breech end

Its filling up

I have a pressure gauge on the air chamber AHEAD of the piston

Here is the link I found details on how to make this type gun

http://home.comcast.net/~glenshindel/Sp ... o_page.htm


If ya scroll down there is a cool annimated gif and the details I posted above

I am filling it with a compressor - I have a 5HP in my garage.....

I also have a pressure gauge mounted on the air chamber at the reducer end - it fills up and registers nicely.....

I tried it at 40, 60, 80, 100 PSI nothing- It seals up FAST, holds air - hit trigeer.... nothing but air comin out ...

Here are the pics...

What do you mean equalization hole ?? My piston seals against the barrel fine... it leaks a TINY bit sometimes but you cant tell unless you tape plastic over the barrel end-then it fills up and pops it

ANOTHER PICTURE GUYS

Here is my diaphram / piston thing.......

Hey guys.....

Well I built a 'Spudzooka' yesterday and waited till this AM to test....

hooked up air....Nothing..... RATS !!

I have the 'modified diaphram' design I found on a site - basically 2 diamphrams srewed on each end of a small PVC coupling - like a 'diaphram piston' I made the metal ...