# Grave popper Cylinder Help



## HauntCast (Jul 25, 2008)

I'm finishing up this Grave pop up. I still need to paint the tombstone. I want the head to come up higher, but I would need a cylinder with the right length stroke. I'm using a Husky bike pump, but am thinking about using a cylinder instead. What size cylinder would I need if the height of the Tombstone is 33 inches?
http://www.discountvoiceovers.com/Video/GravePopper.mov


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## joker (Sep 25, 2007)

It's going to depend on how you connect the prop to the cylinder. In your setup as a simple pop up, the distance the prop travels is a 1 to 1 ratio to the stroke of the cylinder. A 12" stroke gives you 12" of lift.

If you were using a scissor type mechanism or 4 bar you can get more lift without the need of a long stroke cylinder.


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## the_PROCRASTINATOR (Oct 14, 2006)

The Longer the stroke the way more expensive!
A 33 inch stroker on ebay will cost you almost $100 or more!
I agree with Joker, scissor type mechanism or 4 bar you can get more lift without the need of a long stroke cylinder.


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## dynoflyer (Oct 8, 2006)

Keep checking eBay for pneumatic cylinders, you might get lucky. I got 3 new 16" throw double acting cylinders for $60 +shipping last month. I'm using two of them and sold one to my neighbor at my cost. 

Haunted Homestead will be "jumping this year!"


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## uncle (Sep 26, 2007)

DJ-

As mentioned, a simple 4 bar will help magnify the throw of a cylinder. In the attached picture, simply moving the attachment point along the lower bar will change the lift.


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## HauntCast (Jul 25, 2008)

Does anyone sell those 4 bar devices or can anyone tell me what stock to buy to build one of my own?


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## Lotus (Nov 12, 2004)

1/4" flat bar aluminum
1/8" angle aluminum


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## Lotus (Nov 12, 2004)

Chris I can make one for you if you don't got a drill press


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## The_Caretaker (Mar 6, 2007)

evilusions and Devious concoctions sell it


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## HauntCast (Jul 25, 2008)

Lotus, I think I found some parts at the hardware store that will work. I'm going to try using some strip braces and some pvc. I'll try that this week and see what happens. I think it will do the job.


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## HauntCast (Jul 25, 2008)

Uncle, How long is the bar attached to cylinder? What are the measurements of all the parts?


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## uncle (Sep 26, 2007)

The two main bars are 12" long, and the aluminum angle piece is 4 1/4". The holes are drilled at approximately 3 1/2" apart on both the angle piece and the extending piece. I would suggest a minimum length on the 2x4 of 24" so you have at least a little extra to experiment with cylinder placement. Of course it can always be longer. Afterwards you can cut it shorter if necessary.

The extender piece length is pretty much dependent on what the specific prop requires. 

Just as an FYI, for a tombstone pop-up With a wig head on and the 2x4 cut down as far as I could get it, I found that a tombstone of 30" would be about right.


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