New guy on the block needs help

[EIGHTWGT]

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 disks and gaskets on my little lathe so its pretty precise I guess.....

I have nop idea whats wrong =(

[PCGUY]

Could you post the link to the page that you saw this modified diaphram on?

[BC Pneumatics]

If it was the origonal "spudzooka" I'm not all that suprised. That design is much more complicated that it really needs to be. We could help you more if you gave us a few more details. Did any air come from the barrel? Did it make a hissing sound? What did you fill it from? (Hand pump, CO2, Compressor, etc)

[EIGHTWGT]

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

[EIGHTWGT]

ANOTHER PICTURE GUYS

[BC Pneumatics]

Just wondering, you do have an equilization hole, right? If you are filling via a hand pump, then you may not be creating enough force to puch the piston forward again. Try inserting a return spring, or an aircompressor if this is the case.

[PCGUY]

I merged the topics... no need for 2 topics to be made.

[EIGHTWGT]

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

[EIGHTWGT]

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 the trigger.

[EIGHTWGT]

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

[PCGUY]

I'm not an expert on pistons and such but after looking at that animation you see how when it's filled air goes around the sides of the barrel? Then when the blowgun is triggered that air is the air that pushes the piston open to fire...

I don't think yours is filling up around the barrel.

How fast does it fill up when you fill it?

[EIGHTWGT]

Its filling up

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

[BC Pneumatics]

Yeah, I have a strong feeling you are only filling your pilot chamber.
Ypu need to drill/cut a hole int the piston, leading from the pilot chamber to the main chamber. DO NOT make a hole leading to the barrel, this would make the spud come out of the barrel as soon as the compressore is hooked up, and land about 5 feet away. Hold up, I will make a pic, just to make sure you get it.


The arrows are the path of the air (pretend the piston is sealed)
The hole should be about 1/8th inch.

[BC Pneumatics]

Oh, I just saw your other post. Could he have a pic of the entire cannon? and is the pressure gauge reading parallel to what your compresor is putting out? Also, does ANY air come out of the barrel when you fire?

Also, does your pilot take a while to empty, or is it pretty much instant? (around 3-10 milliseconds)

[EIGHT]

Oh, I just saw your other post. Could he have a pic of the entire cannon? and is the pressure gauge reading parallel to what your compresor is putting out? Also, does ANY air come out of the barrel when you fire?

Also, does your pilot take a while to empty, or is it pretty much instant? (around 3-10 milliseconds)

My pilot takes abot 1.5 seconds to empty

Chamber is same pressure as the guage/tank I fill from

the gun looks just like a Spudzooka - a 72" 1.5" barrel inside a 48" section of 3" pipe...... you can see the end of it but Ill post a pic if everyone needs to see more