I was just messing around with it at first. First order of business was to eliminate the nozzle and enlarge the airway.
I wanted to test it to see if it was even worthwhile, so I e-taped it to some 1/2" PVC. Damned if the thing didn't get some range (tight mega stefans in PVC)...
Of course, just hitting the end of the plunger doesn't make for good accuracy. So, an internal spring was needed. Turns out the plunger came apart nicely, and I hacksawed off the cap. I happened to have a good size spring around.
I cut slots in the end of a small dowel, and then glued the plastic to the wood. The plunger rubber actually fit directly on the wood, but there would have been nothing for the spring to attach to, or push against. You can also see the trigger notch. I decided the easiest way to get thing thing going was to use a Nerf technique, and make a notch that can catch against the back hole. Push down on the rod to fire. It'll wear quickly because it's just a notch in wood, but this is just to get it going, anyway.
As it happens, the 20mL syringe I used has nearly the same diameter as 1/2" PVC. All it needed was one turn of e-tape to make it snug.
Good things about the concept: a syringe has a really good seal.
Bad things about the concept: a syringe has a really good seal. I don't have a very powerful spring in there, but it doesn't pick up much velocity.
Oh, and I just realized, I really need to trim that dowel. Duh.
It currently can get about 30' (measured) with really tight mega stefans. Here's a movie of it firing...if only because the sound it makes cracks me up.
Is this practical in a war? Right now, of course not. But it looks like a syringe might be a nice source of ready-made plungers for other homemades. Easy to work, and cheap...the one I used was 40 cents.
Edited by Carbon, 15 July 2007 - 08:14 PM.