6 replies to this topic

[xedice]

http://img48.exs.cx/...xedice_tmp1.jpg
http://img48.exs.cx/...xedice_tmp4.jpg
http://img48.exs.cx/...xedice_tmp5.jpg

I constructed this one a while ago. Vintage's topic (http://nerfhaven.com...?showtopic=2797) inspired me to become not so lazy and take a picture of it, since his design is almost exactly like mine. I didn't want to hijack his topic, so I made a new one. It is modeled after a TMP, poorly at that, I didn't want to make a frame for it, so you are essentially holding the air tank in your hands.

It has a detachable barrel, onboard pump salvaged from a super soaker bought at target, and a zero valve hooked up to the trigger. The trigger has string on it, so that when you pull the trigger, it doesn't bend out of shape, it stays in it's 90* angle. Also, I did use a nested barrel because zero valves open slow even with a fast trigger pull, so in result, the pressure has time to build up in the nest.

Ranges are not exact, they are comparative to my other gun's range, meaning I measured only once for all the guns I tested, so these ranges are a few feet off, and I didn't measure the the inch, just the nearest 5ft mark. The ranges are pretty poor for the pumps needed, due to small pump, small zero valve, darts too light for this gun.

8 pumps ~ 70 ft
8 pumps ~ 75 ft
8 pumps ~ 55 ft

16 pumps ~ 85 ft
16 pumps ~ 80 ft
16 pumps ~ 80 ft

If I were to remake this gun, I would make the airtank a tad bigger, use a MUCH bigger pump, and use a bigger zero valve with 3/4" PVC instead of 1/2".

Edited by xedice, 27 August 2004 - 12:49 PM.

[Ironman]

Nice ranges and gun. Did you use differnt darts every time because the range changed every time?

[ShortShit]

I like it. I like small homemades, and im glad the zero valve workedout for you.

[Vintage]

because zero valves open slow even with a fast trigger pull

Yeah, I know Zero valves don't let out the air very fast. I want to make a variation that will. I have an idea on paper if you want to see it.

Anyways, I am glad the design works for you! I really want to try the pistol, because it could show that a small airtank under high pressure will work well in a homemade. Your airtank doesn't look much bigger than the one I was planning.

~Vintage

[Zero Talent]

Key Valve:




Just an idea I had a few months after those first valves... Because those first valves had that annoying flow rate issue. Using something large, like 7/16" OD Aluminum rod for the sealing bits on the key, you could have fairly nice flow rates. Besides that, you can polish the edges to prevent any and all o-ring wear. Just use a really small (1/8"OD or less) threaded steel rod with a matching drill tap. Easily adapted to larger or smaller key/o-ring sizes.
Haven't gotten around to building one, but unless solid mechanics have abandonned me, it should work for the same reasons all the others do.

Edited by Zero Talent, 28 August 2004 - 01:31 AM.

[xedice]

When I range test my guns, I am also range testing my darts. That dart that got around 55 feet at 8 pumps got thrown away right after I tested. I range test with a different dart each time so I can see the general range of the gun.

Sure vintage, show us your idea, I'm always trying to think of cooler valves to use and I would like to see yours. I might try zero's key valve on my next homemade and see how that performs. And I am also a fan of small airtanks high pressure. I mean, look at a AT2K's tank, its tiny! but still good ranges. Those homemades with huge airtanks and long pumping times are just a waste in my opinion. Well thanks for the input people.

Edited by xedice, 28 August 2004 - 03:20 PM.

[Vintage]

Ok, here is the design of the valve:

The o-ring to the right is fixed to the metal tube and will seal against the rubber gasket with the help of the spring. The o-ring to the left will be fixed to the CPVC and will seal the rear of the valve.

The rounded front of the metal tube is a cap of either hotglue or Plumber's Goop. It helps guide the valve back to the center of the hole, and seal the tube from the air output.

The undecided factors are the size of the metal tube, and the size of the o-rings and gasket.

~Vintage