This is the area that you will find what others have to say about SpudZooka and our products. Feel free to leave a message with us.
12-2-2002
Just wanted to thank you very much for making the SpudZooka plans available free, that's really decent of you, they are the best and clearest plans that I have found yet.
Here in New Zealand its hard to get PVC rated above pn12 so I thought I'd make a steel one instead. I used a old hydraulic cylinder and length of 32mm id heavy wall tube for a barrel, (exact size for D battery.)
Basically a SpudZooka design with a Diaphragm/piston made out of a 12mm disc of nylon with rubber both sides. Works great and extremely reliable. Shoots straight through 6 by 2 inch timber every time at 105psi. I am looking forward to higher pressures as the cylinder is rated to about 2200 Psi !
Using the cylinder, half the work was done already and you can easily change barrel diameters.
Kind regards,
Gavin Mcewen
Editor Note - Pics can be found on the Photo Page.
10-19-2002
Good day, Glen. Thought I'd drop ya an e-mail. Your SpudZooka is quite
the device, I must say. Mine's built pretty much to the exact specs given in
your plans, with some small changes of my own. The device is lethal, impressive,
and gets attention wherever it goes. We've got an utterly amazing 800 yards
range under the right conditions, @ 80 PSI, but a consistent 500-700 yards is
always promised. I was wondering how I can get some of those "SpudZooka"
decals you have, to put the finishing touch on my well detailed cannon. I've
become a serious Spudder, it's become a hobby as well as an obsession. I have
further designs to try this winter, one has a
rifled barrel. Some of my friends have a combustion powered cannon, but you're
right, it's shamefully pathetic compared to the SpudZooka. If you could e-mail
the information on how to obtain some SpudZooka decals, I would be appreciative.
Thanks, Glen,
Kevin P.
Editor Note - Another happy Spudder, that is what it is all
about! I will be sending his SpudZooka decals soon.
7-7-2002
Thanks for a great set of plans - My 12 old son is on cloud nine or
rather our first test shot of a 2 inch potato plug is! That first shot must have
hit the jet stream and is on it's way to Arizona!
The diaphragm ate up a whole day in construction - the rearmost gasket simply would not make a good seal against the cleanout plug. 1/32 gasket material is hard to find so we used 1/8 & 1/16 which is readily available. We made several attempts at creating the perfect gasket until Taylor (12) came up with the award winning solution. We provide it below in the hopes you will pass it on in your plans.
Taylor noticed the rear 1/16 gasket kept folding and failing to seal so he convinced me to cut a gasket and glue it to the clean out plug thereby slightly modifying your design. In essence, build the diaphragm with the 1/8" gasket material and bolt it together with a 1/32" piece of steel (we used T6 aluminum scrap which doesn't bend very easily). Then cut another gasket from the 1/8" material, cut a 3/4" diameter hole in the center, and glue it to the inside face of the cleanout plug.
The 3/4" hole allows air to pass through it inbound from the line supply, accommodates the bolt in the diaphragm, and best all creates a large flat surface area for the steel plate of the moving diaphragm to seal against. Worked first time like a charm!~ I also suspect that the small hole in the middle helps center the diaphragm as it moves backward when the unit is triggered.
I guess it takes a kid to see the solution! I maintained we just needed to make the gaskets better. Oh well, it works.
Thanks again,
Zach B. Altadena, Ca
6-7-2002
Hi Glen Great news! I've finished another cannon. This time it is much smaller,
but all steel construction :) and it works great. Check it out at my website http://www.chr1s.b0x.com/Minicannon/Minicannon.htm
I've sent you a few extra pics that weren't put onto my site but feel free to
post them or link to my page from your website. My camera obviously isn't the
greatest, so I don't have very many pictures right now. Eventually though, as I
do more shooting, I'll take some more pics of both of my cannons for you. Let me
know what you think,
-Chris
5-17-2002
My son, an engineering student, was assigned a project to design and
build a machine to shoot hockey pucks in the same fashion as the machine used
for batting practice with baseballs. The puck was to go 60 mph. I got to help. I
found your website and much of your information was extremely helpful. We built
a pneumatic cannon with a 66" rectangular tube of aluminum and oak, used a
steel freon tank (600 cubic inches), 2" steel pipe 14" long through
the tank and 3" steel pipe for the diaphragm section. (welded construction)
At the presentation, only 35 psi was used and the puck tore a hole through the
goalie's net being used for a backstop. Estimated speed was 75 mph and the prof.
was impressed. Grades aren't in yet but I'm sure he'll do alright. We static
pressure tested everything to 150 psi and shot it at 120 psi once. We'll never
find that puck.
Along the way we came up with a couple of ideas that you may find useful. We put
the diaphragm on the end of a 1/4" bolt about 3" long with the head of
the bolt sliding inside the 1/2" air delivery tube. Even though the bolt
head is a very sloppy fit it effectively prevents the diaphragm from cocking. A
spring in the tube helps hold the diaphragm open although it's probably
unnecessary.
Our design has the diaphragm separated from the puck by the 2" dia X 14" long pipe. At first we thought this may be a problem as that much air is wasted space in the chamber. Actually it may be an advantage for the following reasons. While that air is compressing there is a short delay allowing the diaphragm to get more fully open. There is more momentum of air flowing past the diaphragm before the puck starts to move. This air being compressed (like a spring) contributes to the energy of the projectile. If you had a graph that showed the pressure in the barrel for each inch the projectile moved the area under the graph would correspond to velocity and energy. Having this delay results in more area under the graph. The peak pressure would occur later in the barrel. It's kind of interesting but I don't know how you'd use it in your design. Maybe just don't put the potato all the way down the barrel - resulting in a similar airspace. Try that but be careful, chamber pressure may be higher.
Thanks again for your help I'll send some pictures.
-Mark
Editor Note - Pictures for this can be found on the photo area.
2-23-2002
The parts arrived yesterday, Friday. Today we launched and it was a big
success. The cannon worked perfectly and we got all the
necessary data for the experiment.
We controlled at a low psi (just 20) because in the city it's hard to find big
open areas, but even so the potatoes went over 200 feet. we went through a
lot of them, like 30 launches. took some pictures, too. If you'd
like, we'll send one.
At the end we could not resist doing one launch at higher pressure, 40psi.
quite a sight, quite exciting. it is a very elegant device.
There was much drama ... will the parts arrive in time, will it work, did we do
everything right ... which made the success all that much more fun.
Many thanks ... Nick and Steve
Editor Note - This was a father son project for a science fair.
1-6-2002
I built a close proximity of your SpudZooka. I've played with
combustion spudguns on and off for a couple of years and with out question your
design rules Thanks keep up the good work.
- Steve