2011 APH M2

[wetmonkey442]

So the glue was barely dry on my first APH when I saw some potential for improving the design. I'll let the pictures/video do the talking and answer questions as best as I can.












http://smg.photobucket.com/albums/v258 ... 0663-1.mp4

[marauder]

Very nice. What kinda range are you getting on it?

[wetmonkey442]

Currently I'm getting around 40 feet before the pump starts leaking considerably. The next step is going to be to expand the PC for increased shot time.

[marauder]

Nice. Are you going to bring it to the war?

[HBWW]

I've been searching endlessly for that elusive, holy-grail homemade water pump that doesn't leak. Might be onto something, but I've hit a few roadblocks in the plan. The idea is to put the O-ring on a 3/8" OD bolt, which goes into a hollow, 1/2" aluminum rod. The problem is, you need 7/16" OD on the bolt to be able to tap the dowel, but I cant find one with a head that'll also fit into the 1/2" PVC. In the end, I epoxied the 3/8" bolt into place but I don't trust this to work for long as a lot of force will try to pull the bolt out.

Experiments aside, the most reliable method I have used right now is to simply put the O-rings directly on the dowel, then carefully use epoxy putty to create spacers and keep the rods in place. You may also be able to find and use the nylon spacers typically used for nuts and bolts, but they are unlikely to fit into sch. 40 1/2" PVC. (I forgot to try when I was at the hardware store today so I don't know.)

[wetmonkey442]

The homemade pump I use actually doesn't leak at all, but it's a little hard to move for my tastes. I'll post a picture of that soon. In the video I am using a stock pump off of a CPS 1-3-5. The reason for the leakage (I believe), is that the walls of the PVC pipe are significantly less smooth than the plastic they use in stock blasters, and the rubber gasket has trouble conforming. I might look into constructing the pump shaft out of a different materials.

In your plan, the head of the bolt only needs to be large enough to hold the o-ring against the edge of the aluminum, right? In that case, I could just grind down the excess bolt head so that it is able to slide freely in the pipe.

In studying and comparing pumps I came across an interesting design difference between Water Warriors and Super Soaker. Water Warriors uses a very simple single o-ring fitted into a grooved shaft, whereas Super Soaker uses a more complex rubber skirt that is longer and raised at both ends.

@M4: There is a good chance that I will try to make a third one before the end of the summer which incorporates an improved pump, smaller trigger valve and all metal 1/4" cross between the PC and check valves in order to reduce dead space and increase lamination. If I do, then that is the one I will be bringing to the war.