# air compressor question



## hallloweenjerzeboy

I would like to start getting into Pneumatics and have an air compressor question. I have a 6 gallon 90 psi 150 Max bostich air compressor. How many props can be run off one compressor like this?


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## stagehand1975

It depends on the cfm rating or how fast it makes air. 6 gallons is a good storage size but it is possible to use more air than what it can make. You could probably comfortably do 5 simple prop on that. But the movement you do the more air you will use. The higher the cfm the better. You could do more than 5. It just depends on the complexity of the props. Oh and your victims per hour as well. At worst it will run non stop which really isn't good for it.


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## hallloweenjerzeboy

Hey thanks for the Reply, What is cfm, I just do a yard haunt but I gave all my props away because Im getting married and getting an apartment. I am going to rebuild slowly for when we are in a house and I want to make pneumatic props this time to start.


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## fontgeek

CFM is the volume of air your compressor puts out, it stands for Cubic Feet per Minute.
Another variable in your equation is the prop(s). Not all props are created equally, some require more volume and or pressure than others to do their thing.
Noise is also a factor, especially for haunts. Many compressors are loud, because they were intended for construction or work sites they, the manufacturer, tend to not worry about that issue. For haunts, the noise can be a major factor in creating your illusion.
If your compressor is noisy, then you can either move the compressor to some remote location where the noise level won't be an issue, get a quieter compressor, or try to mask or live with the noise.

Your compressor is probably not designed for long term, continuos use. From your description, it's probably made for powering things like a nail gun, a stapler, etc., tools that get used for only a couple of minutes at a time, and that don't require massive amounts of volume/CFM of air.


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## hallloweenjerzeboy

Thanks for the great info. This is my compressor. BOSTITCH CAP2000P-OF 6-Gallon 2.0 Peak HP Oil-Free Compressor:Amazon:Home [email protected]@[email protected]@http://ecx.images-amazon.com/images/I/[email protected]@[email protected]@41UAd1ikyWL if I have to get some specifically for the haunt, do You recommend any as well as any sites to get the best deal.


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## scarybill

It is a small one like said before. Some things that can be done is use another air tank for more volume. Think of use this way, bigger diameter, more use, longer stroke more use. more weight you move= more pressure needed for same size cylinder. YOu will be fine for a while. Good Luck


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## hallloweenjerzeboy

How do You get 1 compressor to run multiple props?


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## FrightProps

Not sure how far down the rabbit hole you want to go, but we've made a ton of tutorial videos and manuals for pneumatics. Give it a glance and I'm fairly confident you'll find what you're looking for.

http://www.frightprops.com/faq/category/2/pneumatics.html

And if you're looking for videos, this link should take you to all of our pneumatic related videos:

http://www.youtube.com/results?search_query=frightprops%20pneumatics&sm=3


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## craigsrobotics

Depending on the size of your cylinders, length of airhose runs, number of times per minute you cycle the animations, you could easily send this compressor into a burnout/thermal shutoff with only two props. and if you use reservoir tanks at each prop, you need to make sure you use check-valves at the inputs to the tanks from the compressor. Keep in mind the more air tanks you daisy-chain onto the circuit, the longer the compressor will have to run to refill those tanks...check out the duty cycle on the compressor also.


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## fontgeek

This is where having one of those big 220 volt compressors with a 90 gallon tank/reservoir, and lot's of horsepower comes in handy. With it stuck in a remote location, you can run hoses or lines out to your various props. You can buy or make manifolds/splitters to get multiple hoses or lines running from a single outlet from your compressor. Having regulators on each line allows you to keep the air pressure at a steady level for each prop or mechanism. Filtering your air is also strongly recommended. The addition of a big compressor also allows you to use sprayers, airbrushes, etc. Don't get me wrong, your little compressor is great at doing what it was designed for, but it's really not built or designed for a long night (or more) of powering props. When the little compressors go, they tend to be expensive to repair or replace.
THe longer the hoses or lines, the more connections or fittings, the more air volume and pressure you lose to leakage.
When in doubt, buy bigger and heavier duty compressors and hoses than you think you will need.


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## niblique71

If you have 10 TOT'ers a night, that canister might run 3-4 props, But if you have 600 it might only run 1 prop with a small cylinder and even then it'll be running constantly. I personally like the belt driven ones which are usually 2 cylinder and are MUCH quieter or at least way less annoying.Lowes sells them for about $450, or you can buy a used one. 

I have a 33Gallon 155CFM which would be great for most home haunters for a LONG TIME. I want to upgrade to a 220V higher capacity one, so I might sell mine to someone local for a fair price.

PM me since you are local. We have met before at the NJ Pa meetings.


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## Abunai

hallloweenjerzeboy said:


> How do You get 1 compressor to run multiple props?


Air manifold.


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## Hippofeet

Compressor Math!!

Oy Vey.

Here is a page....http://www.cagi.org/pdfs/CAGIAirCompressorHP.pdf


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## fontgeek

The math isn't difficult, just add all of the peak pressures needed, and the combined CFM/volume needed, and you will know the most that would be required of your compressor.
If you are going to go out and buy one, double your numbers. It's better to have more than you need than need more than you have. While you may not think it likely, you have to plan on all of your props going at full tilt at the same time, hence the combined pressure and volume requirements.
Make sure your hoses are rated to carry whatever the maximum pressure combination will be. If you are setting up your compressor in a remote location, and sending one large hose out to a manifold in your haunt, then that main hose has to be able to take ALL of the pressure that will be divided up between your props at the actual haunt site.


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## Hippofeet

Add all of the peak pressures needed? So if I needed 80 psi in 4 locations, that would add up? Doesn't make sense.

How do you know the CFM/volume?

If I have a 2 inch bore, 8 inch stroke cylinder, that's 25 ish cubic inches of volume, but compressed at 80 psi? So running twice (in and out) for 10 times an hour is 500 cubic inches of volume moved through the system in an hour, and then convert that to CFM? 

Why would I divide up the pressures between the props? Seems like it would be the highest pressure required, then regulated for individual props. I thought it would be like this is the highest system pressure, period, so if the main hose takes 150, then I can't run a higher pressure anywhere anyway. Except in the case of a hellevator, where the occupant load will increase pressure on the lines, and that's a prop that is probably going to have its own compressor and system anyway.

Seems pretty difficult, to me at least, to calculate ahead of time a complete pneumatic setup, even knowing the exact size and pressure requirements for every pneumo prop on site.

Am I making this too difficult?


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## fontgeek

Think of it this way, if all of your props were firing off at once, you would need the total/combined pressure of those props to make them work. If you don't have enough pressure, then some, if not all, of the props either wouldn't work properly or maybe not at all. You have to plan on a worst case scenario as being the normal condition/situation.
If you just have the total pressure running to everything, you may end up blowing out valves, hoses, fittings, etc. If you have one hose putting the maximum pressure to your props, and one of those props blows a seal or something, then you lose the use of all of your props 'til you either isolate/remove that prop, or get it repaired. All of your air leaks out through the rupture in your system/blown prop. Putting a separate pressure regulator for each prop lets you keep them running safely and consistently, and gives you a way to adjust or fine tune their pressure levels without having to mess with all of your props adjustments.
Most equipment shows or lists it's pressure and volume needs.


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## Hippofeet

All that up there ^ makes sense.

I was kind of hoping for some numbers, like some examples of a theoretical set up. 

The haunts I have worked in usually go big, to allow for expansion, anyway. Still, I would like to be able to engineer a system from scratch. 

Compressor math, here I come.


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## Hippofeet

So like this, I guess.

Let's say I have 3 pneumatic props. A set of ankle whips, a pop-up behind a tombstone, and an air blaster.

the ankle whips can be set at any pressure between barely moving and screaming pain. So, 40 psi. On a controller set up for 5, 1 second bursts. All 1/4 inch tubing and fittings.

The pop-up is on a step mat, the skeleton weighs 15 pounds, running on a 12 inch, 1 inch bore cylinder, with the starting angle set so that it is not requiring a bazillion pounds of force to start, then smashing through the rest of its travel. So in a dream world, it takes 30 psi to operate smoothly. It is on a step mat trigger, so the "on" time is going to vary, however, because it is a cylinder, the volume moved per triggering event will be the same. Up, then back down. On a 4 way, it's pressurized both ways. Want it to have some zing.

The air blaster is loudest as 120 psi, and is aimed away from faces. It is on a PIR, through a Maestro controller running a 110VAC 1/2 inch solenoid. Programmed for a 2 second blast, then running "off" out to the full (what's a maestro, 4 minutes?) 4 minutes programming time, to prevent constant triggering.

There is a total of 150 feet of 3/8 poly poly airline, with 2, 3/8ths tees reduced to 1/4 for the whips and the pop up, and a straight 3/8ths into the blaster. 

The blaster has a 5 gallon accessory tank, located within 5 feet.

I mean, that's doable for the average yard haunt, right?

So, what is the compressor required? Just "a big one"?

Not just to run them, that is easy. But to set it up correctly so that the compressor stays within its ideal state, not running constantly, so enough volume to stay just ahead of requirements, and enough poop to kick it back up to the required pressure quickly.

Last year, the haunt had 200 people a night (time to go into business, right?) for three nights over a 6 hour period each night.

That's what I want to be able to do the math on. Otherwise, I am officially lame.


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## niblique71

Please don't hate me for this response... it's just a common sense "Farmer style" approach to pneumatics. No I'm not a farmer but I often see how they solve common and uncommon problems with brilliant simplicity.



Abunai said:


> Air manifold.


Simply put ; an Air manifold is a device that splits the air from one line into many lines, just like a garden hose splitter where it splits the water flow from one house to 2 or more.



fontgeek said:


> Think of it this way, if all of your props were firing off at once, you would need the total/combined pressure of those props to make them work. If you don't have enough pressure, then some, if not all, of the props either wouldn't work properly or maybe not at all. You have to plan on a worst case scenario as being the normal condition/situation.
> If you just have the total pressure running to everything, you may end up blowing out valves, hoses, fittings, etc. If you have one hose putting the maximum pressure to your props, and one of those props blows a seal or something, then you lose the use of all of your props 'til you either isolate/remove that prop, or get it repaired. All of your air leaks out through the rupture in your system/blown prop. Putting a separate pressure regulator for each prop lets you keep them running safely and consistently, and gives you a way to adjust or fine tune their pressure levels without having to mess with all of your props adjustments.
> Most equipment shows or lists it's pressure and volume needs.


I agree with everything above



Hippofeet said:


> So like this, I guess.
> 
> Let's say I have 3 pneumatic props. A set of ankle whips, a pop-up behind a tombstone, and an air blaster.
> 
> the ankle whips can be set at any pressure between barely moving and screaming pain. So, 40 psi. On a controller set up for 5, 1 second bursts. All 1/4 inch tubing and fittings.
> 
> The pop-up is on a step mat, the skeleton weighs 15 pounds, running on a 12 inch, 1 inch bore cylinder, with the starting angle set so that it is not requiring a bazillion pounds of force to start, then smashing through the rest of its travel. So in a dream world, it takes 30 psi to operate smoothly. It is on a step mat trigger, so the "on" time is going to vary, however, because it is a cylinder, the volume moved per triggering event will be the same. Up, then back down. On a 4 way, it's pressurized both ways. Want it to have some zing.
> 
> The air blaster is loudest as 120 psi, and is aimed away from faces. It is on a PIR, through a Maestro controller running a 110VAC 1/2 inch solenoid. Programmed for a 2 second blast, then running "off" out to the full (what's a maestro, 4 minutes?) 4 minutes programming time, to prevent constant triggering.
> 
> There is a total of 150 feet of 3/8 poly poly airline, with 2, 3/8ths tees reduced to 1/4 for the whips and the pop up, and a straight 3/8ths into the blaster.
> 
> The blaster has a 5 gallon accessory tank, located within 5 feet.
> 
> I mean, that's doable for the average yard haunt, right?
> 
> So, what is the compressor required? Just "a big one"?
> 
> Not just to run them, that is easy. But to set it up correctly so that the compressor stays within its ideal state, not running constantly, so enough volume to stay just ahead of requirements, and enough poop to kick it back up to the required pressure quickly.
> 
> Last year, the haunt had 200 people a night (time to go into business, right?) for three nights over a 6 hour period each night.
> 
> That's what I want to be able to do the math on. Otherwise, I am officially lame.


Love your stuff dude...Top notch

Now for the comment: LOL

I think the best way to approach this is much more simple and far more mundane than any geeky calculation can achieve. Most of us get started in pneumatics small and build one prop which almost ANY compressor can handle for one night (Except a 12V emergency tire inflator).

DO THIS....

Forget the compressor calculation stuff... just get the biggest compressor you can afford and it'll probably run that one prop.... NOW, if you want to upgrade to two or more Pneumatic props, see if your first compressor is breathing heavy (Panting for it's life) during your first Halloween night. If so.. GET A BIGGER ONE for the next year.. as BIG as you can afford.... Continue this theory and advice ad infinitum until you retire from Halloween...

Professional haunters??? You also do NOT need a calculator... just get the biggest Mother ***** compressor your haunt budget can afford... and test and test and regulate air pressures and retrigger times, and test some more until you find an equilibrium that works for your haunt... OR Buy a second compressor and keep adding aux tanks until you find an equilibrium. Calculations are not only boring and mundane and take away from build time, they only work if you can accurately predict your crowd flow and habits (A huge unknown for most normal haunters).

3rdly, you CAN buy a small compressor, and if the "Calculations" (LOL I know)and pressures are set just right, you can Piggy back two medium compressors together to give yourself enough air flow to upgrade without loosing your initial investment of the first compressor. You just have to set the regulators on the back up one so it will only come on under higher demand for air. and goes off before the main one does. It takes some time to work out the best settings on each compressor, but it can be done.

Finally, if you know your going to build several pneumatic props AND you can afford it. get a 2 stage belt driven compressor. they are quieter and deliver more CFM at a higher pressure than the "oiless" Buzz Bombs...Also the most common reason for not having enough air once you start running multiple pneumatic props is air LEAKS... Eliminate them COMPLETELY and you'll have far more air for your night. As mentioned in previous posts "Use regulators" at each prop to dial in the air usage and prop movement. You might have to dial a prop down a bit to share more air for other props. Upgrade next year

In summary, Build, Test, fiddle, Upgrade: build test, fiddle, upgrade. etc...It might be a little more expensive overall to do it this way but it reduces the initial investment for a first timer. It will also allow many more of us to participate in the wonderful world of Pneumatics instead of keeping potential first timers from getting started....


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## Hippofeet

"I would like to start getting into Pneumatics and have an air compressor question. I have a 6 gallon 90 psi 150 Max bostich air compressor. How many props can be run off one compressor like this"

lol. I know, I go off on a tangent sometimes. But sometimes I really want to know HOW something should work. 

Niblique and Fontgeek, what you guys describe is what I do now. Pressure regulators, run and test, watch and listen, all that. You are right on with your advice, IMO. I mean, that is how it is done, no doubt. Even at Pro Haunts. At least the ones I have been involved with.

But the OP's original question, in my mind, remains unanswered.

Like others have said, the answer can, absolutely, be "depends".

I just feel like I should be able to offer a range of pneumatic devices that operate within that compressors parameters. 

I'm not trying to be pedantic here, seriously. And I will, gracefully, let this go. But I will have to look into this further, it's a problem I have. Why can't I , off the top of my head, say " Oh, 6gal. 90 PSI compressor? Well, with 5.6 SCFM you could run such and such, or this or that."

I mean, jeez, I only work with this stuff everyday. Now that the question has come up, I feel like I am lacking some vital skill set.

It's gonna bother me.

I'm going to go work out, and think about it.


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## bfjou812

Hippofeet said:


> Compressor Math!!
> 
> Oy Vey.
> 
> Here is a page....http://www.cagi.org/pdfs/CAGIAirCompressorHP.pdf


Try starting around page 14....................


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## niblique71

I admire your tenacity and determination. Despite my earlier advice, I did seek out CFM and Output pressure needed for( I think) a 1.5"- 14" throw cylinder for "Karl". I determined that I'd need between 70- and 80 lbs of force to lift Karl by hooking up a rope in place of the cylinder and hanging a single pulley and a bucket from the ceiling of my shop and added weight until he lifted up. I Found a cylinder calculator (Google it), and determined that I'd need a minimum of 80psi just to lift him. The CFM wasn't really an issue since this prop was slow and cumbersome and only triggered once a minute for 1 cycle.

Reality didn't match the calculations and I ended adding a helper spring to get him through the most geometrically difficult part of the lift (The start).

Anyway, Find a good cylinder calculator online, and at least you'll get CFM's per cycle as well as Force per psi for any particular cylinder sizes. That should get you into a good predictable air usage range for your cool props 

If you really want to get technical, unlike hydraulics, Air cylinders actually use more CFMs as you give them more pressure per cycle


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## fontgeek

Most pneumatic equipment comes with estimated ratings for both pressure and CFM requirements, that being said, those ratings are often lower than reality, and they still leave the variable of the load you will actually put upon them. The heavier the load, the more pressure it's going to take to lift it or move it.
As already stated, I'd get as big a compressor as I could fit and afford. It's much easier to make a big compressor do small work than the other way around. Smaller compressors are often much more expensive too.
One of my airbrush compressors was close to a thousand dollars when I bought it twenty-some years ago. You pay for the portability and the reduced noise levels. That compressor has a six gallon tank, but for that price or even less I could get something with a fifty or sixty gallon tank and a much bigger compressor. Granted, it would be noisier and not really portable, but for most people, the portability isn't really much of an issue.
I'm sorry there's no easy or magic answer for you on this. You are not alone in this battle though, and it will get easier for you as you get more experienced.


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## scarybill

Here is something that happened to me two years ago. I was building a crypt with a top the lifted up. I figured the weight of the top and thought a 1 1/16" cyl would open it at about 70psi, using a cylinder calculator. WRONG, it ended up taking 90psi. OK you say, "you only missed the calc by 20psi". True that was not the problem. The problem is that the air compressor pressure switch operated from 75-125psi. This said, after a few cycles it quit working. The air had made its way down to 80psi. Not enough to open the prop, but not low enough for the compressor to come back on.
Just a little something more to think about. When I replaced the cylinder(with a larger one) I made sure it worked at under 60PSI. I would recommend this for anyone that is planning a pneumatic prop.


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