3 inch piston help

[cannon monkey]

Hey guys Im in need looking to build a new toy but I don't know what to use for a piston I'm looking to fit into 3"pipe bout 2-4 inchs long any ideas

Thanks in advance,
Monkey

[Gaderelguitarist]

Make one from wood, or make one from pvc fittings.

[squidchicken]

yea wood or pvc fittings, anything solid and not too heavy, could maybe make a huge fibre glass piston

[cannon monkey]

I tried 2 inch couplings their too small and there no stores near by with 2.5 anything any ideas???

[Technician1002]

Fiberglass is fragile. I would recommend something with much higher impact resistance. PVC is too brittle too for that size. I had a couple of cannons that used inverted pipe caps for pistons. The Mouse Musket used a 1 inch piston and the Dragon used an inverted 2.5 inch pipe cap. The larger pipe cap is a little large to fit in a 3 inch pipe. I had to machine the piston and pipe on a lathe to get them to fit. Both cannons using PVC pistons broke them.

If you have access to a lathe, UMWHDPE or HDPE round stock from McMaster would work well. It has good impact resistance.
I use that in my newer QDV cannons and it is holding up very well.

HDPE has a mass slightly less than water. It makes great light pistons. They are less than 1/4 the weight of steel.

[cannon monkey]

I was lookin into the hdpe stuff but it cost so much

[jackssmirkingrevenge]

[c9d]

I went out and bought a set of white HDPE cutting boards, a 3" hole saw, a round rubber flap valve for a toilet, some rubber gasket making material, tennis balls, a proper length bolt with nylon locknut, and all purpose cement. Made the 3" barrel sealing piston for my coax cannon, no problem.

[cannon monkey]

I just got 3" hole saw but it not right size

[motorfixer1]

Go for the HDPE stock from mcmaster like tech said. If you want to play you gotta pay.

[MochaDesign]

Hockey pucks fit 3" perfectly. We haven't encountered any problems using them yet, and the best part is that you don't need any gasket material. The rubber face of the puck should seal just fine at ~70-110 psi (from our testing).

-John and Andrew

[Labtecpower]

but he doesn't want to spend money

[Technician1002]

In related news, I want a Bugatti Veyron, but don't want to spend the money.

If you have a drill press you can make the right size.
http://www.spudfiles.com/forums/tutoria ... 21740.html

[Labtecpower]

SO.... If you don't want to spend money, stop asking, use your brains, and be creative! you should be able to find something suitable for a piston.

[mark.f]

Hmmm, jack has a fairly good suggestion. Fillers such as open-cell foam could make the piston lightweight and reduce epoxy consumption as well.

I agree that paying NOTHING for a piston is a little optimistic. Even a deodorant can piston (a la MrCrowley) requires rubber gasketing and some hardware (and if you use roll-on you're stuck buying a deodorant can as well).