My attempt at a CPS Homemade

DX · Post by DX » Mon Jul 24, 2006 1:44 am

^The final product should look roughly like that. Not quite, but the drawing is as close as I could get it to be. However, I can't start this gun until the Regional War .

Silence · Post by **Silence** » Mon Jul 24, 2006 2:06 am

Looks good--I'm sure the proportions will be slightly better in real life, as you said. Layout-wise, you could also have the horizontal part of the reservoir below the PC to make everything a little more compact, but I might have overseen something as usual...

More importantly, I think you could just order as little LRT as you need from McMaster-Carr now, assuming that's what you're missing and that you intend to get some from Ben at the Regional War. Ichabodv got his the same day he ordered it, so it's entirely possible that the shipping won't be a problem unless the only warehouse they have is pretty far away...

Anyway, good luck with this soaker. It's nice to see more support for CPHs, and I wish I could make one!

DX · Post by DX » Mon Jul 24, 2006 2:26 am

It won't fit under the pc. I learned that early on, around my 3rd homemade. I would have to make the gun much taller to do that, which would lose compactness overall by being taller. I also like having the pump as close as possible to the ball valve. If a gun has to be either longer or taller, I always take longer. My battlefield also favors longer rather than taller guns.

I can't buy anything from McMaster-Carr. My mom won't let me buy anything else other than SM-related expenses via her credit card. She's paranoid about giving the credit card number online [my parents are not much in-tune with the digital age]. I turn 18 in November, so then I will have my own card.

Drenchenator · Post by **Drenchenator** » Mon Jul 24, 2006 3:04 am

This looks pretty good so far. It really is about time that someone other than Ben is going to build a CPS homemade.

One thing though, I think that you really need to make the bladder casing a lot larger. Ben used 4" pipe to contain it for a good reason, the latex rubber expands like mad. A few inches (6 to 8) can expand to at least twice or even three times in length and a few times in diameter too.

An advantage of using the tubing is the massive chamber capacity. In the third video, Ben pumped the gun 30 times (though the gun can be pumped up many more times). Since the pump volume is about 60 mL, then (very) roughly 1.8 liters are in the chamber. The casing really needs to be large if you want to maximize the performance.

Once you do this, you may also want to increase the capacity of your reservoir too since the chamber would be very large. Again, it really is great to see people attempting to build CPS homemades.

SSCBen · Post by **SSCBen** » Mon Jul 24, 2006 2:14 pm

Once I get some more money, I'll order you a second tube to stack over the inner one. You'd definitely want that. Let me know though, and add $9 to your tubing costs if you would want it.

If you use a design more similar to mine, you also can put the reservoir on the bottom. Cable ties will hold it to the second check valve area. The water gun would be a little awkward to hold, but the reservoirs on most water guns look awkward to being with - that's why I use backpacks.

It's also a shame that you can't get things from McMaster-Carr for a few months. They're located right in New Jersey, and if I get my orders in a day, you'd get your orders in hours.