# Compressor alternative?



## joker (Sep 25, 2007)

I happened to see a truck today loaded down with various gases (oxygen, acetylene, CO2, etc...) and it got me to thinking about the days I used to play paintball. We used a lot of C02 and compressed air to power our pneumatic guns.

With the proper regulators I wonder if you would you be able to power pneumatic props with compressed air? You can rent/fill tanks pretty cheap. 

I guess it would all depend on the amount of volume needed for a nights worth of haunting.

Any thoughts?


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## time2dive (Dec 29, 2007)

I run all of my pneumatics using scuba tanks. I use a scuba regulator to drop the pressure down to about 125 psi and then use standard pneumatic stuff after that. I scuba tank will run a prop all nigh long. The other advantage of air tanks is that you can use batteries to run the solenoids and then have a remote prop.


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## joker (Sep 25, 2007)

time2dive said:


> I run all of my pneumatics using scuba tanks. I use a scuba regulator to drop the pressure down to about 125 psi and then use standard pneumatic stuff after that. I scuba tank will run a prop all nigh long. The other advantage of air tanks is that you can use batteries to run the solenoids and then have a remote prop.


Thanks for the input time2dive!

I may have to pull out one of my compressed air tanks out and see how long it would operate a prop. What size scuba tank do you have? At what pressure?


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## hauntedcampers (Jan 1, 2007)

i used a CO2 tank at the campground but you have to watch out not to freeze the regulator. Worked nice no noise


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## time2dive (Dec 29, 2007)

I use either 72cu' tanks or 80cu' tanks at either 2400 or 3000 psi. 80 cu'= 640 gallons of air.....so they hold considerably more air than those 6-30 gallon air tanks that come with compressors..... The only problem is that a scuba tank cost between $50-150 depending if it is used or new. An air fill costs $3-6 to fill. I have lots of scuba tanks AND I work at dive shop so air is free for me.....makes things easier.


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## Gory Corey (Nov 17, 2006)

FYI, bang for the buck, go CO2.
CO2 compresses to liquid under 700 psi, and comes out as 8cu ft and change per pound, air will not compress nearly as much.
A 20# tank will yield 174 cu ft for 1300+ gallons of gas. 
This is smaller than the 72 or 80 cuft 2800 psi air bottles.
You can rent co2 tanks for a few cents a day, or buy them outright.
If you rent them, you can avoid the hassle of transporting them and have them delivered to your door 

I did all the research some time ago while calculating yields for the BoomPak from a 2.5# bottle.

Ignore nitrogen, its a waste.

Dive air has to have specialty gear to refill tanks and the shop should insist you be padi or such certified to refill tanks.

CO2 can be had at any welding supply, or AirGas distributor, and all you need is to walk in with either a tank, or arrange a rental

Heck we offer Aluminum co2 set ups for our Boomer Cannons with everything ready to go for running props. Includes a very nice micromatic single stage hand settable regulator with lock ring, 10' coil hose and quick disconnect outlet .


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## randyaz (May 26, 2006)

off topic...but... i wonder if welding shops are going to have to tack on a charge for CO2 carbon offsets in the near future...


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## Gory Corey (Nov 17, 2006)

Doubt it, CO2 is an extracted gas not a mined gas like helium.
It is not like you are putting any more into the atmosphere than is there already.


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## Revenant (Mar 17, 2007)

The liquid CO2/expansion chamber method was what Creative Visions did to power their Rock Monster when they put him on a parade float. Lasts a good while, and a lot safer than using high pressure gas tanks.


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## joker (Sep 25, 2007)

As C02 warms up it expands. I'm considering adding a prop in my hearse, but C02 wouldn't work as the inside car temps would cause the burst disc on the tank to blow. Would compressed air say like in a scuba tank be ok in a warmer temp like inside a closed up car?


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## Revenant (Mar 17, 2007)

I would think it would be exactly the opposite. In a compressed air tank, the pressures are already very very high... the pressure soars when heated; they have warning labels on scuba tanks not to leave them in a car. Liquid bulk CO2 is a lower pressure system; pressure doesn't become an issue until the temperature exceeds the safe working limit of 130 degrees. Are you planning on parking this hearse w/props in the summer sun for long periods? If so pneumatics probably wouldn't be a good approach; you'd be better of with actuators.


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## mandodude (Aug 31, 2008)

Rev is right. Scuba tanks and heat (in the trunk in the summertime) are not good companions.


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## Gory Corey (Nov 17, 2006)

joker said:


> As C02 warms up it expands. I'm considering adding a prop in my hearse, but C02 wouldn't work as the inside car temps would cause the burst disc on the tank to blow. Would compressed air say like in a scuba tank be ok in a warmer temp like inside a closed up car?


Unfortunately you are left with nitrogen for your purposes, at 1800 psi you get about 20 -30 cu ft per bottle.

I would ask a local gas supplier about the thermal expansion, as I have heard of it being used with cars for effects purposes.

Another alternative is a portable on demand compressor and tank system for low pressure air system (sub 150psi) used by a lot of low riders.
That is a proven and I believe safe method and takes almost no engine load.


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## time2dive (Dec 29, 2007)

The burst disk on a scuba tank is set to blow between 125-150% or 4000-5000 psi for a standard scuba tank. Yes a car does get warm, however not that warm. For every 1 degree of temperature change you will get a 5 psi change, so to get you 1000 psi extra you are going to need to get a 200 degree change in temperature If you have a defective burst disk it may go early. They are designed to blow in case of a fire.... the burst disk blows before the tank does.
I routinely keep scuba tanks in my vehicle here in Hawaii, I have not had one blow yet.

Tim


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## GhoulishGadgets (May 13, 2010)

Hiya,

One year, I used an old car wheel, pumped it up and used a with a home made (converted bike pump) air ram, operated by a low voltage solenoid, the whole prop powered by a car battery (LED lighting, sound, sensor and solenoid control)

The power wasn't as strong as a compressor, but operated well all night.
(without the need for cables and pipes across the yard)

Si


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