Re: Compressed air


Daniel Koller
 

Hi All,
   There is no such thing as "canned air" really.   All of the "canned air" products on the market have some sort of gas (not air), which when compressed, becomes liquefied.   It is the vapor pressure of the liquid which provides the pressure to blow off the dust.  As you let some gas out of the can, more evaporates to maintain a relatively constant pressure until the liquid runs out, and then the pressure quickly drops.   
    If instead you take a old can of "canned air" and put a Schraeder valve on it so you can re-fill it with an air compressor and put actual air in it, you will be sorely disappointed (as I was).   The physics is pretty simple and the pressure will just decrease exponentially as you let the air out of the can, and it rapidly becomes useless.   I get about 5 seconds of useful dusting pressure out of a can before I have to re-fill it.  It's good for a blast or two. 
   I HIGHLY recommend using an air compressor and plumbing your shop as opposed to using portable canned air products.  Even the Non-CFC versions are really nasty stuff to the environment.  They don't kill the ozone layer, but they contribute substantially to global warming.  See:
https://www.epa.gov/sites/production/files/documents/dusters.pdf

  I don't mean for this to roam off-topic, but since it was brought up, figured I'd mention it.   Also hope no one wastes their time trying to re-fill a duster can as it just doesn't work.
Dan

On Wednesday, May 1, 2019, 10:19:01 AM EDT, David Kuhn <Daveyk021@gmail.com> wrote:

I plumb the shop with a compressed air (and a compressor in the garage).  I
use a small dryer in-line with the spray naucial (sp).

On Wed, May 1, 2019 at 10:13 AM Caveman <digcam1@roadrunner.com> wrote:

Photographer as well as a repair tech here, and I say do not shake cans of
commercially available compressed air used for blowing dust away. They can
splatter whatever is in the can onto lens coatings, or in the old days
negatives, ruining them.

Not knowing what is in the can, but knowing that it can blow droplets of
whatever it is into what you are cleaning means that while you are blowing
dust away, you are also blowing moisture of some kind on what you are
cleaning. If that moisture is oily then it will become a dust collector.

I’ve heard some say that you can invert the cans of compressed air, like
Dust Off or other dust blowers, to use them for cold testing components. If
so just be sure to clean up afterwards.

FWIW,
Don Kemper


On May 1, 2019, at 9:17 AM, cheater cheater <cheater00@gmail.com> wrote:

Ah, I somehow lost the first sentence of the email which was: "should one
shake compressed air or not?"

I guess i need to learn how to post!

On Wed, 1 May 2019, 14:53 cheater00 cheater00 <cheater00@gmail.com
wrote:

I hear conflicting reports on what one should do. What's your take?
Are there different types where you should or shouldn't?

Druckluft 67 (aka Dust Off 67) from Kontakt / CRC says not to shake
the can "or otherwise the fluid might come out", but is it always the
case with all types? What is that fluid for, anyways?

I read reviews of some cheaper compressed air products on amazon and
they complained about the quality. What can go wrong with compressed
air? Two things people brought up were one brand produced very weak
pressure, and another produced flammable rather than inert gas.
Druckluft 67 touts as being oil free. Are there other things that
might go wrong?

Why would someone use canned compressed air rather than an air
compressor?

Thanks.




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