# Can I operate a cylinder under water?



## robp790 (Jan 8, 2008)

I saw a neat prop in the Distortions catalog, an Acid spitter. I have every thing to make this prop,(in my mind) But I wondered if the pneumatic cylinder (double acting) can operate under 2 feet of water. I reason that as long as the valve is outside the barrel and only air is going thru the barrel it should be fine.

Now to find the spitter portion?


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## tonguesandwich (Oct 13, 2006)

This is one way on how you do a water pop up. Don't use pneumatics. You use a good strong pump, like to drain a pool (60bucks). This is vague but you connect (plumb) it into the bottom of a piece of PVC. On and overlapping the PVC is a larger piece of PVC that is sealed at the top... Thats your piston, the water from the pump pushes the top piece up and the when the pump is turned off, the prop comes down. You attach you head prop on the piece of PVC that is the top of your piston. The best thing to do is fiberglass your monster so it has weight to sink and it is waterproof. The trick is to drill a lot of little holes in the top of your prop so air can escape and sink back down. Water props are really easy once you change your thinking from air movement to H2O pressure.
Add bleach to your water so it doesn't get stinky on you. If you want a spitter, add air through an external valve. Your spitter can pick up water from your barrel or pool, where ever you prop is staged. You do not need air for awesome movement.

THINK SIMPLE... this is not complex. Picture, blowing a straw wrapper off a straw, except your mouth is a water pump. Does this make sense to anyone but me?


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## slightlymad (May 25, 2006)

perfect sense


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## Spookineer (Aug 20, 2006)

Yes, a pneumatic cylinder will operate under water. Just be sure to dry out the entire mechanism when done.


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## gadget-evilusions (Jan 26, 2007)

Make sure you are also not using a steel bodied cylinder. Most good cylinders are stainless bodied with aluminum end caps, and as long as the fittings and mounting hardware are also aluminum or stainless, your parts can stay under water just fine. Then you can just run your air lines out of the water and to your solenoid valve which should be enclosed in a water proof housing if anywhere near your barrel.


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