Its my second post, and here is my first spudgun! It cost me about $ 50, and took most of 4 (5?) days to assemble and cool-ize. 8) I built this gun from the highly modified Green Hornet plans from the Boogieman, adding a bunch of accessories and features. Thx Boogieman! You can pretty much see every thing in the pics, so feel free to skip the description.
Without the silencer, the C:B ratio is about 1.25 to 1, with it is about 1 to 1. The barrel is 43'' in length, made of 1.5'' PVC, but it has holes for the silencer for the last 5''. These can be covered or uncovered by preference.
The chamber is made of 2'' of 2'' sch 40 PVC, 9'' of 3'' PVC, and 3.5'' of 4 PVC. However, the fan and batteries take up a small amount of space inside the 4'' PVC. Inside, I used a dual ignition setup, with one contact at the front and the other at the back, both powered by a grill clicker. In the back section, I also threaded a removable lantern lighter (see pic) between the contact, making 2 sparks instead of one. However, when the lighter is in, it results in a small leak.
Now, for the extra features... As I already said, I put a cheap fan in the chamber, along with a color-changing LED (Just for looks, of course) with a battery pack for it. The fan's battery pack is external. I made the barrel breach loading, but because I am cheap, it is a screw-in. However, loading is still much faster. Also, I attached two handles to the barrel for a comfortable grip. The silencer, one of the cooler accessories, is made from the left-over length of the chamber and barrel - 1.5'' surrounded by 3'' PVC. The inner barrel had holes cut in it, and the outer is packed with cotton. The assembly slides about 5'' onto the barrel, making the whole gun a hefty 6' 2''! I painted the barrel black, added a glaze, and covered the chamber in duct tape. I also added some semi-corny labels and pics that I made in flash pro and online.
UPDATE- To make the gun look more "professional", I repainted the whole gun a cool glossy black. I covered the handles and chamber in electrical tape for looks, durability, and insulation. I renamed the gun the WMD - Weapon of Mashed Destruction. Sorry if that has been used, but hey, it sounds cool. I also cleaned up and rewired the chamber, resulting in a much larger spark and a more reliable fan and light.
I have not been able to test damage or distance, because I have only shot it in my back yard 5 times. With a burst disk of painter's tape, the sound it makes is amazing! It is louder than a real gun, and a half-foot jet of flame shoots out the barrel!
It shot a milk cap about 40 yards on 2 seconds of OUST. I was able to shoot two potatos, but they were both cooked, so they were too soft. 
Because of this they only shot pieces about 50 yards, shotgun style. I can only hope for better performance with uncooked potatoes.What do you guys think? Will it go farther with them? Remember, my barrel is 43'' long , but it has about 4'' of 1/8'' holes drilled at the end. With 1.25 to 1 C:B ratio, do you think I can expect better performance? Also, what ammo do you recommend? UPDATE - I tested it with uncooked potatoes, and to my relief, they shot MUCH farther. I can only give a rough estimate, but I would say they flew 200 yards at least. To see distance pics, go to page 3. NO damage pics yet though, as my parents are not cool with me blowing things up. I'll post them sometime, though.
When I loaded the pics, I accidentally put them in reverse order. oh well.
I hope they are good... :thumbup: UPDATE - Here are some new pics of the less ghetto launcher. Check out that 360!! As far as I know, that's a first on the boards!
Gotta love flash! Also, here is a really short and crappy video of the test shot. http://video.google.com/videoplay?docid ... 2247252260
UPDATE x 2 Hey people, I finally posted the damage pics! also, here are two videos:
http://video.google.com/videoplay?docid ... 4279&hl=en - This one shows the gun shooting a spud at a board. The laughter in the video- not me. Funny in slow-mo.
http://video.google.com/videoplay?docid ... 3614498301 - This one shows the potato penatrating a 1/6'' board and the chair behind it! I found pieces of the chair 30' away!
These videos turned out kinda crappy for some reason. They looked fine on my computer though.
? (pneumatics that is)