The only problem is that I don't feel like building PVC pistons from scratch
again. I decided to see if I could convert a cheap storm & screen door
closer into a piston that would work for another grave jumper.
| The screen door closer I bought was from the local Home Depot and
made by Wright Products. It was just under $8.00. It came with
an adjusting screw hole in the end that looked like a promising location
for a pipe fitting.
One side of the hole had a piece of metal for the mounting bracket in
the way, so the first task was to cut it off with the cutting wheel
attached to my angle grinder. |
Screen door closer
 |
| Next step was to drill out the existing hole and tap it for a 1/8
inch pipe thread. I kind of guessed at the pipe size while I was
at the store and it turns out that 1/8 inch pipe thread is perfect for
the hole. |
Tapping piston for 1/8 in pipe
 |
| Once I had the end of the piston threaded I test fitted the elbow
that I picked up while on my search for parts. I had a lot of help
from an employee at the local hydraulic fitting supply shop. He
found me the perfect barb connector, but they were like $10.00 or
something. He came up with the idea to use just a threaded elbow
which cost under $2.00 - Thanks man!
The drill bit, tap and tap handle ended up costing me $23.00, but I
figured that now I have the tools to make as many of these pistons as I
need. |
1/8 inch pipe elbow
 |
| For testing I put a small regulator in-line and started working up
the pressure until I found a good action that was not too rough on the
piston. Anything below 30 PSI was barely enough to move the
piston. I ended up at about 55 PSI and it has a really good
action. I took it up as high as 65, but at that pressure the piston
was really hitting hard on the top of the stroke. There is a
danger of blowing the piston apart if I put too much pressure in it.
I do not know if the piston will hold up over time or not. If
you decide to try creating your own piston this way, you are
responsible. I am putting a pressure regulator right at the prop
so that when the day comes where someone cranks up the compressor to
120+ PSI I won't blow something or someone up. |
Testing the piston
 |
The assembly you see in the image to the right is what I ended
up with. I connected the 55 PSI hose connector to a small electric
valve that I picked up a few years back from a pneumatic supply shop.
I attached that to a T fitting and ran it through to the piston.
The pressure gauge you see attached to the T fitting is just there to
release the pressure from the piston when the supply valve is closed.
The released air will be used to operate an air horn or something
similar to add to the scare. The final assembly will have a
pressure regulator in line so I can fine tune for the specific prop and
protect the piston from any radical adjustments someone might make to
the main supply pressure.
I have an X-10 switch hooked up to the electric valve. That
allows me to use my X-10 remote control (or even my PC) on Halloween
night to activate the prop. |
Finished piston assembly
(click on image for video) |
