Thread: Pneumatic Cylinder from a Bicycle Pump *HELP*

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Hello all,

Long time lurker, first time posting. Anyways.

I'm building a second pneumatic pop-up for this year and I need an improvised cylinder with a longer stroke, so I have decided to go with a bicycle pump. I have read about props that use them so I know they are fairly common, however, I have not been able to find a detailed guide/how-to on converting them into a cylinder. I was wondering if anyone around here has any first-hand experience in using bicycle pumps in their props.

BTW- I am fully aware of the possible safety issues such an improvised cylinder could cause


Thanks so much,
~M!

Here is one link.
Pumpkin Popup

Thanks, however l have already read the material on Wolfstone; unfortunately it is quite vague.

Maybe this will help.Good info.
Haunting With Compressed Air
Use it as a "GUIDE" will not walk you thru step by step.But it shows what you need to make it work.Then just put the airhose where the air comes out of the pump and the pump will go up when triggered.Even step by step could be different as not all pumps are the same.

No, are clearly not aware of the dangers, if you were you would not be wasting your time.

Home made pneumatic cylinders from a bicycle pump or anything else are the dumbest and possibly most dangerous things you can do.

Go and spend $20 and buy a proper pneumatic cylinder that wont kill people when it explodes!

"dumbest and possibly most dangerous things you can do" ? so mom was wrong about running and sissors? And I thought last year it was open flame in a haunt.

joking aside, compressed air creates a new level of risk with or without a pneumatic cylinder. I was at the HauntX in 2007 and came to booth with an air cannon. It went off and I got pelted in the face by something off the lady in front of me. My first reaction was can i still see? and then cool, how do I make one of those? At the same show, I watched the sales guy get clocked by a pneumatic. More recently I have beem using a popup sprinkler without a problem. (see below)

I guess, we will all take risks, just be aware of them, be aware of them and attempt to design the prop to reduce chance of injury.

I agree that a bike pump is a device being used as not intended, but also dont assume that just by using a cylinder makes it safe!

[ame=http://www.youtube.com/watch?v=4-ojhn8xstc]YouTube - bobblehead[/ame]

Using a cylinder does'nt make a prop "safe". It makes it designed properly. Using a product for what it is designed for is what makes it safe. Just like a sprinkler valve isn't the way to go . Air and water are 2 different animals and need to be treated as such. With the abundance of products that are affordably priced and the wealth of information that is available there really isn't any reason not to do pneumatics correctly, meaning using parts that are designed for pneumatic applications. Just my two cents worth.

I have been using PVC for my pneumatic cylinders for the last few years and have not had any issues with them.

Now understand that I AM NOT RUNNING THEM AT A HIGH PRESSURE!!! I use schedule 40 PVC and the cylinders are by no means airtight.

I drill bled holes at the top of the stroke so the air will vent before any pressure can build up.



The cylinders are lubricated with glycerin so they move very freely.

The stroke shaft is attached to the frame using weed eater line that is ungodly strong at two points.



But most important is that I AM NOT LIFTING ANY REAL WEIGHT! If you want to lift something that is more than a couple of pounds (stuffed head and a shirt) than get the proper tool for the job.





I run at around 25 – 35 psi that will lift what I need at a speed that is well suited for my prop. The props that run at higher psi’s scare the hell out of me. Phoenix AU may know something about this, “Go and spend $20 and buy a proper pneumatic cylinder that wont kill people when it explodes!” Sound good to me.

PMT

I guess the dozens of people on this board, granted most were from the good ole days, are stupid for building a trashcan trauma using a bicycle pump.

Using a bimba (or similar) cylinder doesn't make your prop safe. You are still building something that could be pretty dangerous.

But in reality, filling your tire with air is a dangerous act. Common sense prevails. Most of us regulate the pressure at our props...

I don't let people get remotely near my props. They get close enough to activate, but I keep them away using fencing, sawhorses, crime scene tape, etc.

Originally Posted by propmastertucson

The props that run at higher psi’s scare the hell out of me. Phoenix AU may know something about this, “Go and spend $20 and buy a proper pneumatic cylinder that wont kill people when it explodes!” Sound good to me.

PMT

Sorry guys I've forgotten the link, but its on this forum somewhere, I was touting the link about this time last year......from memory they are 3/4" cylinders with an 8"-10" throw.... ie exactly what you would expect from a bicycle pump or door opener and at $20 a pop.....