[ezekiel]

Howdy,

I have a question about a screen door closer. Actually I'm looking to build some pneumatic props as outlined by Steve Hickman at Terror Syndicate. The majority of his home made prop designs call for storm door closers. I'm not sure if I'm going to go the route he details or just buy the air cylinders.

The question I have is what is the standard stroke of a storm door closer? And is there a particular bore size I should be look for if I decide to buy the air cylinders as opposed to modifying storm door closers? Thanks.

 

[TheEighthPlague]

I'd buy the cylinders. Especially if you own your home and would like to keep it that way. If the door closer blows up and hurts someone, that's on you. If a cylinder that is used as the manufacturer recommends blows up, that's on the cylinder manufacturer.

 

[propboy]

I agree with above post BUT faulty design and the cylinder blows up it is still on you.

I would still buy the cylinders. I built a TCT with a door closer more than 10 years ago and it is still working great. BUT I would start with real cylinders if I was going to do it over!!

Plus if you get your hands dirty in pneumatics you will need to learn the cylinder and solenoids sooner or later cause many great startle props are air operated and once you start you will be building tons of pneumatic props

-PB

 

[bfjou812]

Definetly NO screen door closers. They aren't made to be used as an air cylinder. Skelatal Remains has a real good, easy to understand tutorial on the basics of pnuematics in the tutorial section on this forum. I also thought I saw a "caculator" for sizing cylinders. The size of the bore depends on the weight of the object, how much force is required to move it and the psi being used. Hope this helps.

 

[ezekiel]

Well that is what I had planned on doing, purchasing my air cylinders, as long as the price is right. But what is the standard throw of a storm door closer?

I just measured my front storm door and it appears to have a bout a 6" throw when the storm door is extended open all the way. Does that sound about right for anyone who uses storm door closers in props?

 

[Stitches]

When I went to the Midwest Haunters Convention, the guy from Evillusions taught a class called Pneumatics 101. In that class, he told us over and over NEVER use a screen door closer. I'm not sure why but I think you will be fine with what you are making.

 

[bfjou812]

Well that is what I had planned on doing, purchasing my air cylinders, as long as the price is right. But what is the standard throw of a storm door closer?

I just measured my front storm door and it appears to have a bout a 6" throw when the storm door is extended open all the way. Does that sound about right for anyone who uses storm door closers in props?

Was that without any restrictions, such as chains to keep the door from blowing open too far, or hinges at their limit ,etc. If so that is probably close to what the stroke is. usually you can measure the cylinder body and get a very rough estimate of the stroke. It is not real accurate, but will give you an idea of what you have and what you would need.

 

[yardhauntjunkie]

The reason not to use screen door closers is that they are not intended for that use and they can malfunction terribly. I have heard two people say that they had theirs have the cap pop off and one of them actually had the rod shoot across the street. Thank goodness there was no kids around. I think the main reason people say not to use the screen door closers is that you could possible kill a kid. Plus air cylinders aren't that much more expensive in the long run when you take into account having to modify the screen door closer.

 

[Homestead Haunt]

I would say your 6" measurement is pretty accurate. Go with cylinders w/o question!

 

[bfjou812]

I just found the calculator I mentioned ,it's at Evilusions.com look under calculators and you' ll be able to figure out what you need. Hope this helps.

 

[ezekiel]

Thank you so much for all your help everyone. Now it is just time to get past analysis-paralysis and get my hands dirty!

 

[Scatterbrains]

I would think the problem screen door cylinders blowing up would be not regulating the air going in...

looks like I need to go find some cylinders

 

[propboy]

Don't forget Physics and Geometry. I thought I would never need algebra again, WRONG!!!!
Remember depending on your design the initial force will be MUCH greater than the ending force but yet you keep the same PSI on the cylinder throughout the motion. You will also need to consider how the prop motion is stopped. Cylinder are not designed to be stops of motion. YES I use the cylinder to stop some of mine, this doesn't mean it's a good idea/design. Springs, stops built into the motion are all good ideas.
I know I may have just confused you but as you build props this will make sense. One day you will think back and say " I thouht I heard someone say this, oh ya PropBoy"

Don't get frustrated and ask when your lost. I like Grainger as they return parts you try and they didn't work out. I have exchanged several items that I thought would work but were wrong. A little more pricey but sometimes worth the ease at least for me.

GL
-PB

 

[kprimm]

If you have the cash i would always go air cylinder, but i have used screen door closers on a couple props and not had any problems with them. Of course they are newer and have not had much use yet. Screen door closers are cheap to use but ideally air cylinders are the way to go.

 

[yardhauntjunkie]

The funny thing is that people say they have been using screen door closers for years and nothing has happened. I am going to assume that most likely hood nothing might happen. But god for bid something does you would be held totally accountable, because you altered a part for a use not intended when originally built. However if you were to use an air cylinder for it's intended purpose you might be more safe and less liable. So in the end the money saved by using a screen door closer doesn't sound like that much. Plus when you look at the price difference and ease I don't really think there is much of a difference and I am one of the cheapest people in the world. And no offense to anyone, but if you have to ask questions on a forum about this kind of dangerous thing then it might not be the best idea for you to do it. This might be something that experienced people can pull off. I will be the first to admit that I am not experienced and will end up buying air cylinders when I make a pneumatic prop.

 

[ZombieRaider]

I've got one screen door cylinder prop (haunted clock) and I built everything out of foam so it wouldn't take much psi to open it...I've always adjusted the psi to the very minimum to open it...That being said, my brother in law gave me 4- 3 or 4 inch stroke cylinders last year so I'll be replacing the one in the clock plus building a few more props this year hopefully....ZR