You can buy an inexpensive air storage tank, fill it up with compressed air at the gas station, and use it to run your props. Even if you needed two or three $10 tanks, it would still be a lot cheaper than a decent compressor.
This is actually a workable plan, but it has the effect of shifting costs from the air source to the props and distribution system: you must make sure that your connections don't leak (avoid quick-connectors), your props use very little air, and you exhaust through the valve, not a bleeder.
Such tanks contain enough gas to run your props all night, but bring with them dangers of cryogenic temperatures and extremely high pressures. This is not a project for the amateur hoping to cut costs.
You can get small "spray cans" of compressed air, often used to clean off stuff. Jerry Chavez of SpookyFX has built self-contained pneumatic props capable of numerous actuations on a single can of air. But Jerry specializes in props that are very air-thrifty. Unless you master the art of low-pressure, low-volume pneumatics, canned air will disappoint you.
These are inexpensive pumps designed to be carried in you car and powered from the lighter plug. They are capable of high pressure (good), but only at a very low volume (bad). Such a device would require the addition of a storage tank, a pressure switch, and a power supply. And if you get it all to work, you'll have to replace the pump fairly soon, because the mechanism is made just to top up your tires now and then, not for extended service. The low price continues to be attractive (on sale for $10 as of August 2001), but they aren't really practical.
Your best bet is to borrow or purchase a compressor.
They should hold at least a couple of gallons.
Different manufacturers measure horsepower differently; so comparing horsepower is only effective between the machines offered by the same manufacturer.
When the maker wants to lie to you about the quality
of a compressor, creative means of measuring horsepower (to get larger numbers) is usually where it happens.
The lies start by finding a "peak" horsepower rating and quoting that number (as it were continuous).
If your motor draws too many amps, it will pop the circuit breaker.
Most companies quote running current, but the startup peak can still still pop the breaker.
Air delivery rates are quoted in terms of SCFM (Standard Cubic Feet per Minute)
at a given pressure.
The more props you have, the more often you actuate them, and the more each prop consumes - then the more SCFM your compressor must deliver to keep the props running.
A high RPM compressor will be louder than a low-RPM compressor.
Oilless compressors have a reputation for being noisy.
This is probably because oilless compressors tend to run at higher RPM, and
the higher the RPM, the louder the compressor.
Mid-size compressors are available with a single large tank, or two smaller tanks.
A Wolfstone reader says that there is a performance difference between the two
(if the total capacity were the same),
but didn't remember what it is.
If you have an opinion on this matter, please
contact us.
Generally, anything that can power a full-sized spray paint gun is sufficient for pneumatic props.
If you get too large a compressor, it may trip the circuit breaker when it cuts in.
There are plenty arguments about which brands are better, how large is enough, and oil-sump versus oilless.
We'll skip those issues for now (other than mentioning that).
You can find suitable equipment at:
Note that there are different kinds of compressors, designed for different purposes.
Just because a compressor only has a half-gallon tank, and is rated for 1 SCFM doesn't mean it
is a bad compressor.
It might be excellent for air brushes.
It's just the wrong compressor for this particular job (operating pneumatic props).
I suspect that most home haunters would be happy with:
A big commercial haunt that runs year-round would probably want a much larger compressor
with a belt-driven, cast-iron, oil-lubricated pump.
Shopping for a compressor
When shopping, consider these characteristics:
Every compressor in the range that we are looking at will have a pressure-switch that turns off the compressor
when the tanks are full of air, and turns it back on when the stored air has been used up.
If you manage to get the right size compressor and storage tank, the compressor will turn on only occasionally,
and most of the time, the props will run (quietly) on the stored air.
If you get the wrong size, the compressor motor will run all the time, and you will have a significant noise problem.
Such a compressor would also be capable of running most air-operated power tools (one at a time).
| air volume delivery | |||||||||||||
make
| model
| power | source motor
| noise
| type
| weight
| storage | tank max | pressure @40 PSI
| @90 PSI
| @100 PSI
| price
| store
| |
| Central Pneumatic |
40400 | 110 VAC ? Amps |
2 HP 3360 RPM |
? DB | oil lube | ? lbs | 8 gal single |
115 PSI | 7 CFM | 5 CFM | ? CFM | $ | HF |
| Hitachi | EC12 | 110 VAC 15 Amps |
2 HP 3450 RPM |
75 DB | oil lube | 60 lbs | 4.3 gal twin |
125 PSI | ? CFM | ? CFM | 3.6 CFM | $247 | HD |
| Campbell Hausfeld |
FP2020 | 110 VAC ? Amps |
? HP ? RPM |
? DB | oilless | ? lbs | 4 gal pancake |
125 PSI | ? CFM | ? CFM | ? CFM | $139 | HD |
| Campbell Hausfeld |
WL506255AJ | 110 VAC 14 Amps |
3 HP 3450 RPM |
? DB | oilless | 62 lbs | 4 gal twin |
125 PSI | ? CFM | 6.2 CFM | ? CFM | $248 | HD |
| Campbell Hausfeld |
WL6500 | 110 VAC ? Amps |
5 HP ? RPM |
? DB | oilless | ? lbs | 13 gal single |
125 PSI | 6.9 CFM | 5.5 CFM | ? CFM | $198 | HD |
| Campbell Hausfeld |
WL504355AJ | 110 VAC 13 Amps |
2 HP 1725 RPM |
? DB | oilless | 56 lbs | 4 gal pancake |
125 PSI | ? CFM | 3.1 CFM | ? CFM | $? | HD |
| Campbell Hausfeld |
WL505855AJ | 110 VAC 13 Amps |
2 HP 1725 RPM |
? DB | oilless | 62 lbs | 4 gal twin |
125 PSI | ? CFM | 4.3 CFM | ? CFM | $? | HD |
This is a Central Pneumatic #40400 from Harbor Freight Tools.
It is the new official compressor for use in our haunt, saving David from lugging his compressor back and forth.
I use it only occasionally (Halloween, and a bit of spray painting), and it seems to work well.
The wheels are a bit cheap - if you move your compressor around a lot, this may be a factor.
Harbor Freight occasionally changes their product line.
As of May 2005, I don't see #40400 listed on their web site,
but there are several that look quite similar.
It is important that the compressor be close to the outlet, because these machines take a lot of power, and ordinary extension cords aren't
suitable to run them. If you have to use an extension cord, make it as short as you can get away with, and use a very heavy duty model.
Remember the adage that "it is better to run hose than wire."
You want the compressor in a remote location because they tend to be noisy when they run.
Count on it - repeat after me "all compresors are noisy."
Whenever the pressure in the storage tank runs low, the
motor will come on.
Unless you can work random engine sounds into your haunt, it will be a distraction - move the compressor away.
Some enterprising haunters have
built housings around their compressors, with sound-deadening insulation.
This isn't a bad idea, but make sure that:
You should read and follow the maintenance instructions that come with the compressor.
Some highlights:
In order to drain condensation from the air storage,
look for a petcock located on the lowest part of the tank.
Open it a little at a time, slowly.
Sometimes you get a little water; sometimes none; sometimes a lot.
The amount depends on how long the compressor has been running and how humid the air is that day.
If you fail to drain the tank, the accumulated water will eventually cause rust inside.
This is unlikely to result in catastrophic failure,
but will probably cause small pinholes, so the tank simply won't hold air anymore.
Given the importance and nuisance of draining the air tank after every time you use the compressor,
automatic solutions have become available.
This is a Central Pneumatic automatic compressor drain kit from
Harbor Freight Tools.
Item #46960-0VGA, $10.99 [October 2004]
Different types of tools require differing amounts of air.
Check the air delivery rate in SCFM (Standard Cubic Feet per Minute) rating on the exact tool(s) you will be using.
Here's a rough list of air tool applications, sorted by increasing air requirements:
Air delivery rates are quoted in terms of SCFM (Standard Cubic Feet per Minute)
at a given pressure.
If you are using more than one tool at once,
take the highest pressure of the tools,
and check the compressor spec at that pressure (or next higher pressure that the compressor lists).
Then add together the SCFM for the tools and see if the compressor can do that.
Example:
Thank you for visiting. Your comments are welcome.
Compressors I have known
![[photo]](pnucmp_Dennis.jpg)
Locating your compressor in the haunt
Once you have your compressor, find a place to put it that is (a) close to a wall outlet and (b) far from your haunt.
Compressor Maintenance
A compressor is a significant investment.
You can't treat it as a disposable thing.
You have to take care of it.
![[photo]](pnucmp_HF_AutoDrain.png)
Personally, I prefer to drain manually.
I like to rock the compressor back and forth a little, and side to side - hoping to get out the last bit of water.
Air tools
I'm just starting to learn about this, but so far, I know...
This is a very conservative way of computing the requirements.
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