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Discussion Starter #1
OK, with Halloween done and knowing how slow rate of speed that I work at, I need to get a jump on projects for next year.

I really want to build some air powered props, just not sure where to start. Does anyone have tips, tutorials etc. I can take a look at?

I want to buy quality cyclinders of Ebay and other places, but I have no idea what size, stroke, etc. HELP!
 

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Im sure someone will shoot me for suggesting this, but I was in the same boat as you a month before halloween and the way I became comfortable with how air props worked was by hacking a couple together with PVC, Door closers and sprinkler valves.

They didnt work like I was hoping, but the amount I learned was priceless and now that I figured it out with a small amount of trial and error, im now decommisioning the two props I built and am going with welded steel and commercial valves and cylinders.

You can either start the way most everyone here has with non-commercial parts and work from there (My recommendation) or you can grab a cheap bimba cylinder from ebay, I would suggest at least a 4-6'' stroke (how far it moves) and a 1 1/4'' diameter rod, a decent air valve (someone else will have to suggest one becuase im in the same boat) but I would still suggest using 1 1/4'' PVC that way you can easily adjust the linkage to get the desired effect.

Here is a quick pneumatic for beginners
http://www.wickedstone.com

**Looks like his website is down, if you would like the .ppf of the file, PM me and ill email it to you.

***I also have a couple of easy 4-bar linkage diagrams that I can email you that will help, just shoot me a PM with your email address if your interested.

Here are a few links I dug up.

http://www.scaryguys.com/slinger.htm
http://www.halloweenpropmaster.com/coffin_sit_up.htm
http://www.halloweenfear.com/Manifold.html
http://www.hauntedillinois.com/pneumatic.php
http://www.virtualplacebo.com/halloween/props/grave_jumper/index.htm

Here is a 4bar program that you can use to help design your linkage, you will have to play around with it to familiarize youself, but once you get the hang of the software, its a great thing.
http://www.boopack.com/software.html
 

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Discussion Starter #3
Thanks Hellspawn, great information

I have been going through all my website links and created a new folder, Air Props, and saving anything to do with air powered props to read on it later. We have a great display and received huge comments on the new FCG this year, but we didn't have much to really scare older kids/adults.

Was thinking about the following using wiper motors and air cyclinders as needed.

Coffin jumper
Monster in the box
Tombstone jumper
Lowboy

I just want to make sure I have a good working knowledge before jumping in on a project and making safety the primary concern.
 

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SS, if you can't find the bimba you want on E bay and you're not looking for one that real big, just go to www.bimba.com and order direct. A typical cylinder with a throw of a few inches will cost you about $20, all brand spankin new. They are used to large commercial orders but they have always been very polite and gave me great service although I was just ordering a single ram.
 

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Discussion Starter #5
I guess where I need to get a good education is, do you buy the cyclinder and design around it or the other way around.

Say I wanted to build a tombstone jumper, do I get the cyclinder first and the go from there. If so how do you decide what stroke size you need if you have not designed the linkage yet?

Almost like what came first the chicken of the egg!
 

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You can easily design your linkage around your cylinder, the only problem would be if you didnt have enough stroke. (and even then, you can still solve it with alittle work)

I suck with trying to explain things, so bear with me here.

For example, you can get the same amount of action in a body slinger (distance your body is slung from rest position) using a 6'' stroke or a 10'' stroke, the placement of the cylinder (further up/down the linkage, depending on which way your looking at it) or length of linkage is what matters.

Dont worry about getting the wrong cylinder, try and stay in the 6'' or higher department unless your wanting to use the cylinder for small movement.

on the body slinger I built, if I position the same 6'' stroke cylinder at different positions on my linkage, I can get more or less action from it.

If I attach my cylinder 6'' from the back of the frame, it wont move as far as if I placed the cylinder 4'' from the back of the frame, but becuase its lifting more, I would need to increase the amount of PSI going to the cylinder.

If I was stuck using a long stroke cylinder, I would place it as far down the linkage to get the desired action (Lifting less=less PSI), if I was stuck with a small stroke cylinder, I would want to put it as close to the fram as possible for maximum action possible.(Lifting more=Lots of PSI)

Hope this helps alittle, let me know if anything isnt clear
 

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Discussion Starter #7
I suck with trying to explain things, so bear with me here.
I think we are in trouble, because I suck at understanding thing... LOL

On a serious note, thanks for the explaination. Make sense not to stress over the stroke but look for something 6" or better and go from there.

I will download the 4 bar software and start playing around with it. I think I will start with something simple like a wig head and mask from behind a tombstone and go from there.

Or maybe a simple straight up motion with a head to get me started etc.

Does anyone use those 5 gallon air tanks or just run everything right off the compressor? I have a smaller size compressor at 15 gallons.
 

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Let me know if this helps.








I used those metal hose clamps in conjunction with the hardware that comes with the door closers, with alittle modification so that I can adjust the position of the cylinder on the bottom linkage, thus adjusting the throw of the prop.
 

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Smelly - there's a book on all that throw vs. ram stuff that will show you a lot of this. It's called "A guide to animated holiday displays", by Edwin Wise. I'm not good at understanding stuff either, but the book will get the point across even to someone as dense as I am. I think it is still available on Amazon.com
 

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Discussion Starter #12
Thanks Hellspawn (nice photos, gives me a good visial) and Dreadnight

I have heard many other using those door closers, so they are OK to use? I wasn't sure if they were safe/reliable to use. I assume they are faily inexpensive to purchase as well.
 

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Ive heard of multiple people using them for years without a problem, I bought the heavy duty type of opener for around 11.00 total, but then you need to consider the additional cost of the brass fittings and tools needed to complete the cylinder (for the air hose to connect too)

The only reason I went with the door closers is becuase I started these projects at the last minute and didnt have the time to wait for some bimba cylinders to be shipped to me.

I bet you can get a bimba cylinder for the cost of hacking a door closer.
 

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Discussion Starter #15
I downloaded the 4 bar linkage software. Anyone have tips on how to use this software?
 

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I will take some pics this weekend and post them up, everything is in storage and it will take that long to pull it out :ninja:

A word of caution, I had issues with my valve and I used the same exact webpage that you have listed.. if you look at how the pictures show how to put it together (note the flow direction of the valve) and then if you look at one that propmaster allready built (in one of the movies) if you look close, you will see that his valve is put together backwards from how that picture shows..

I had a terrible time with mine, but I havent tried to take it apart and reverse the orbit valve to see if that makes a difference.

Alot of people here have built these with great results, becuase of all the issues I had, im thinking I have it backwards, so you will want to try and experiment alittle with it.

Id allmost suggest getting bimba cylinders from eBay, I ended up buying a 1/8? tap and handle to thread the door closer, which was around 6.00-8.00 and with all the brass fittings I used, I think I would have been better off buying a commercial cylinder, as long as you take your time, you will find one for as much or even lower than what it might cost you to build your own, in either case, ill take pictures of everything I have for you and post them in this thread this weekend.

**

I wanted to add on the commercial cylinders, if you have a heavy prop, you will want to use all commercial parts (cylinder/valve) since I would be very weary of putting more than 60-70psi through sprinkler parts, I have done it before, but it scared me to death to keep it up, mabey someone here can add a comment on maximum psi for DIY air props.

I want to buy a mig welder this year and start building prop frames out of steel so I will have to go the commercial route, I cant see a door closer and sprinkler valve lifting anything this heavy.
 

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I downloaded the 4 bar linkage software. Anyone have tips on how to use this software?
Smelly,

Only advice I have is to play around with it, it was really clunky for me to figure out, im still not sure if I have it totally right lol.

Sorry I cant be of any more help.
 
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