I am starting to wonder because the CO2 delivery guys are finding it harder and harder to entrust me with the stuff, and are telling me that my application is unsafe....like I'm hooking it up to a mask and pulling a Dennis Hopper in "Blue Velvet"
I find the 20lb tank with a fine point air gun is a must have for any booth not only for cleaning projectors, but for cleaning platter motor brushes, cleaning lamphouse blowers and exhaust fans and heat sink fans.
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John P. Pytlak, Senior Technical Specialist
Worldwide Technical Services, Entertainment Imaging
Research Labs, Building 69, Room 7525A
Rochester, New York, 14650-1922 USA
Tel: +1 585 477 5325 Cell: +1 585 781 4036 Fax: +1 585 722 7243
E-Mail: john.pytlak@kodak.com
Web site: http://www.kodak.com/go/motion
To John: My 7 plex was Kodak screen checked and they never had anything to say about the compressed air.
The Simplexes at the 4 plex were run by manager/projectionists for 9 years and they were bought used 20 years ago, so they are extremely dirty and are in need of a copius amount of TLC.
Sometimes a tube on the end of a can of dust off is the easiest way to dislodge a bit of crud, but CO2 is generally overkill. I've seen people use CO2 to try to clear backed-up toilets (NOT a pretty sight) and I have used it for cleaning the snot out of coke tray drain tubes... Boy, that came across more sinister than I meant. The plastic tubes under your coke heads... Crud. The flexible tubing under your Pepsi head drain trays. There!
It can be used to dislodge dirt in exhaust vents and around AC and condenser coils, but I'd avoid using it on anything with flexible seals and lubrication. As has been pointed out, that dirt under pressure has to go somewhere.
I have occasionally used a small 20gal horiz. compressor on wheels to help with heavy-duty cleaning of projectors. I have found it especially useful for getting dirty grease/oil out of corners & crevices and out into the open where I can wipe them up easily.
But this is when I encounter a machine that is FILTHY...and by the time the compressor joins the party all of the gears and bearings are laid out on a table away from the casting.
Wow - I never knew about the death threat from air bubbles in the blood! I was already intimidated by how loud this thing is, now I have a reason to be afraid...very afraid.
So, how the heck do those bubbles get into the blood?
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And, hey! Let's be careful out there.
~Manny.
I will run out and get some CO2 right away.
I also use safety glasses that protect from the sides as well.
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And, hey! Let's be careful out there.
~Manny.
As for CO2, I don't think those are the cylinders which punch through walls if the valve gets knocked off. It's high pressure but because CO2 liquifies the pressure stays at about 800 psi. It's the gases that don't liquify at room temperature and stay gaseous whose cylinders are carrying pressures measured in the neighborhood of a couple thousand psi.
And you can use a CO2 cylinder to make dry ice to impress everyone.
As far as projectors are concerned, it is a definate overkill, and can be very dangerous. Some people don't have the slightest idea how much pressure is in those bottles, and how easy it is to get a gas embolism which can kill. Not to mention how dangerous the bottles are if they are dropped and the valve snaps off. The bottles will propel themselves through concrete walls and level everything in its path.
As far as cleaning other electrical/electronic devices, I actually observed one individual who was the head of a certain theater chain (since went bankrupt) who used a full pressure CO2 bottle with the valve almost wide open (to the point where he had to hold the bottle upright to keep it from blowing itself over) to blow out his copier that was in the office. Hunks of drum wiper blades, and other parts (including toner) went flying all over the room. When he was done, he was pissed at the machine because it no longer worked.
He was not the smartest person in the graduating class.
People who use compressed air are usually in a hurry. Now, I'm not knocking them, since they just want a clean projector and don't have much time. But, problems happen when someone takes shortcuts. I can only say I didn't use compressed air at most of the places I worked at, and I thought my projectors were pretty clean. And I didn't spend too much time cleaning them.
Like anything else, common sense has to prevail. Don't crank up the pressure, keep the tank secure, watch what you point it at. I found oil and dirt getting blown onto the lenses, so I made it a habit to cap them.
I eventually found that (for me, anyway) it was better to give the projectors a quick wipe out between shows with a paint brush. Then, once every 3-4 weeks, do a good cleaning (vacumn out with covers removed, wipe oil, etc.) I also check for loose screws, worn parts, blah-blah.
I applaud the use of CO2 to blow out projectors instead of a compressor because of the moisture and oil that is contained in the stream of air. At least CO2 is a source of "dry air".
On the other hand, I don't recommend the use of compressed air (or anything like that) for cleaning out projectors on a regular basis. If you want to use it for the occasional "super-duper cleaning" I would aquiesce but that's as far as I go.
It seems to me that it can take longer to clean out the projector with an air gun than it would with a clean paint brush and a rag. There's overhead involved with lugging around a 20 lb. tank of "air". You can carry around a paintbrush and a rag in your back pocket. When you travel that light you can give all your projectors a right-fine cleaning each and every time you thread the film!
A projector, kept clean in the first place, takes literally 90 seconds to clean with a brush & rag. Try THAT with an air tank!
The same situation with CO2 will cause extreme distress well before a blackout. I, for one, would seek an exit or fresh air at the discomfort stage.
Regardless, using a tank or compressor in the booth is a bad idea.
For dusting, it just moves the dust around both creating a never ending dust problem (it never goes away, just moves around) and coating your platters of film with dust. Vacuuming or wiping is the solution to dust.
For anything else in a projection room - with very few exceptions - it is ineffective, potentially damaging to equipment, and/or dangerous to the staff.
Blowing dust off lamphouse mirrors before cleaning is one job I would suggest a dust-off can or CO2 bottle for. A compressor will often throw a lot of oil and water with the air - not good.
Don't ever play with an air gun!!
Eye damage results from flying debris. Blowing directly on skin can allow air to be forced into the bloodstream, especialy if the skin is broken. An air bubble in an artery will cause a problem, ranging from trivial right up to excruciatingly painful, debilitating, and even fatal.
I found that if I crushed the blocks into powder I got a better fog. So opening night, little did I know, that I put five feet of fog on the stage, engulfing our hunched over scrooge and nearly choking him to death. The first row of people also were choking rather heavily.
Scrooge was and still is played by the director of the show. After the show, he pulled me aside and said "young man, i thank you for the authentic london fog, however, please try to bring it to a more utah mormon level".
The next night the fog failed completely.
My point, yes, you can probably kill someone with that co2, I wouldnt use it. If you want to use compressed air, there is a new system out that you use the same cans over and it has a small compressor that you hook the can up to. It filters out all the impurities and gives you a nice dry air blow. You can find them at most office supply or computer supply houses.
Dave
You can pressurize it with air but when the keg starts getting below, say, half full the air starts replacing the CO2 and making it turn skunky. This is why when you go to a party and the keg is tapped with one of those air pumps the beer starts getting "icky" the lower the level gets... Especially when the keg isn't used up quickly. With the general quality of most commercial American beers, it's pretty icky to begin with. Skunky low-quality beer is even worse.
I suppose when you make your own beer you could force-carbonate it but like he said, good beer should generate its own gas. Otherwise you'll end up with something that tastes more like Alka-Seltzer. 
There are two ways of carbonating beer. The "traditional" method is bottle conditioning, or krausening.
When you brew beer, you basically make a malt-sugar water solution, and add hops, and yeast, then put the solution, or "wort", into a glass carboy with an airlock. The yeast consumes the sugars, and excretes alcohol and CO2. The CO2 escapes through the airlock.
As the yeast consume the sugars, the alcohol increases, and the sugar decreases. Once the fermentation reaches a certain point, the yeast can no longer grow, and become dormant and settle to the bottom of the fermenting tank. The homebrew "standard batch size" is five gallons, because that's the size of the big glass carboys used for fermentation. Once the fermentation completes, the result is a five gallon bottle of finished, but completely uncarbonated beer, with a large mass of yeast on the bottom. The beer is siphoned from one carboy to another, leaving the yeast sediment behind.
This is how all brewing is done. Whether you're Anheiser Busch, or a homebrewer, at this point in the brewing process, you have a large container of finished, but uncarbonated beer.
If you're going to bottle-condition, or krausen the beer, the procedure is to boil a small amount of malt extract (to sterilize it), and add it to the beer right before you bottle it. What happens is that inside the sealed bottle, the remaining small amount of yeast floating in the beer detect the extra sugar, and revive and start to metabolize and reproduce. As the yeast consumes the extra sugar, it produces more alcohol, and CO2. This time, however, the bottle is sealed, and the CO2 doesn't escape -- instead it dissolves into the beer. In a few days, the small amount of newly produced yeast goes dormant, and settles to the bottom of each bottle. The result is a small amount of sediment in each bottle, and natural carbonation.
If you're just starting to homebrew, bottling is part of the learning experience, but once you've been doing it for a while, bottling becomes the biggest royal pain in the neck. First off, you need to get some 48 bottles absolutely clean, or you'll have random bottles of bad tasting beer. Second, you have to get the amount of additional malt extract just right. Too little, and the beer will be flat. Too much, and the beer will be either too fizzy, or even worse, the bottles will spontaneously explode in storage. Plus, making beer is an exercise in kitchen-microbiology and the art of keeping things sterile. The more steps you carry out, the greater the likelyhood of bacterial contamination, which causes off-tastes.
However, there is an easier and better way. Instead of bottling the beer, you use a 5 gallon stainless steel cornelius keg -- a soda-fountain keg -- what they used to supply soft drink syrup in before they switched to boxes. Of course, the keg must be completely cleaned out of any syrup residue and the gasket replaced.
To force-carbonate, you pour the entire five gallon batch of finished, flat beer into the keg, then connect a CO2 tank to the pressure fitting, set the pressure to 40PSI, and vigorously shake the keg. The beer absorbs CO2 so fast you can hear the valve hiss with each shake. After about one minute of vigorous shaking, the beer is fully carbonated. All you need do is remove the pressure hose, and let the keg sit for an hour or so. Then, you vent the pressure from the keg, hook up the CO2 tank to the keg with the pressure set very low -- just enough to keep the beer flowing, and connect a tapper to the keg. Then you tap and enjoy.
Force carbonation is a huge time-saver. It gets you the exact same results as bottle-conditioning with none of the work. Kegs are better at parties anyway, and the beer will stay fresh, because as you dispense the beer, you replace it with CO2 -- no oxygen gets into the keg, so the beer doesn't go bad.
The result is a more predictable brewing process, and in general, better beer. Force carbonation removes a whole set of variables in the process. There is absolutely no quality difference whatsoever between beer with CO2 generated by bottle conditioning, and beer carbonated with CO2 pumped in from a tank.
1. 85psi or 90psi for cleaning can still be quite dangerous. In the US, OSHA limits air pressure for cleaning purposes to 30psi. Specifically, 29 CFR 1910.242(b) says
quote:
Compressed air used for cleaning. Compressed air shall not be used for cleaning purposes except where reduced to less than 30 p.s.i and then only with effective chip guarding and personal protective equipment.
2. On the other hand, DTS recommends the use of compressed air to clean their timecode readers. Page 17 of the DTS-6D manual: "The timecode reader lens should be blown off with compressed air once a day to remove any dust build up."
This thread seems oddly timely; we're just looking at installing compressed air in our principal booth to avoid going through those Dust-off(tm) -type cans. Of course, it's a little differenct since there's already a compressed air plant in the building... We only use air for the DTS readers and for parts of our projectors that are hard to reach by hand...definitely no substitute for cleaning with a alcohol, a toothbrush, and a Webril wipe.
--jhawk
Granted that a blast of compressed air can be invisible and theoretically more dangerous because of that invisibility; still, I find the disparity in limitations indicate the real level of danger.
I do think that pressure washers tend to be used at much greater distances (tens of feet) than compressed air (inches), so I would expect a lot more risk to the eyes from air than water.
--jhawk
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Adam Fraser
www.pinestheatre.com
More likely the pressure washer industry lobbied hard to keep regulations away. High pressure washing is the only way to properly clean some items, and a 30 psi limitation would immediately be met with howls of indignation. Pressurized air OTOH has no "protector" industry and gets the maximum limitations thrown at it that OSHA thinks it can get away with.
IMO, OSHA does some great things for safety, but suffers from overkill and political influence like the rest of U.S. government.
It sometimes reminds me of the mother in "A Christmas Story."
www.pp.okstate.edu/ehs/MODULES/cylinder/theone.htm
I really can't see a health and safety issue here - in a ventilated projection box of 100 cubic metres or so, the odd cubic centimetre of Co2 is hardly going to kill you (unless you squirt it up your nose or practice some other similar fetish). True, you can drown with a teaspoonfull of water in your lungs, but that's got to get in there somehow. In much larger quantities, i.e. from a compressor situated in the box, I can see that C02 poisoning might be an issue.
I agree with John P that compressed air is a waste of time for anything except surfaces which are too fragile to make physical contact with a cloth or a brush of some description - you're only moving the dust, not removing it.
Make sure this is done by someone who knows what is necessary! Compressed air tends to produce quite a bit of water in the lines, and they must be plumbed properly to drain properly.
I've seen booth installations where the air nozzle turns into a rusty water nozzle, one in particular would be fine for months and suddenly supply at least a gallon of nasty rustwater that had collected at a low point in the piping until it finally reached a siphon level.
Unless your compressed air plant uses a chilled or dessicating air dryer you WILL get condensation in the air lines. Try to insist on correctly plumbed pipes and self-draining droplegs.
Also.. unless you have an oil-free compressor (rare!) or you use a coalescing oil filter, the air will also carry a fog of oil droplets.
Likewise, spraying cold liquid CO2 or FREON will likely cause damage and condensation. (Although it can be used to diagnose thermally intermittent problems in electronic components):
http://p2library.nfesc.navy.mil/P2_Opportunity_Handbook/3_IV_3.html
http://es.epa.gov/oeca/fedfac/fflexp2/techtip/env-fs2.html
http://support.tandy.com/support_supplies/doc2/2968.htm
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John P. Pytlak, Senior Technical Specialist
Worldwide Technical Services, Entertainment Imaging
Research Labs, Building 69, Room 7525A
Rochester, New York, 14650-1922 USA
Tel: +1 585 477 5325 Cell: +1 585 781 4036 Fax: +1 585 722 7243
E-Mail: john.pytlak@kodak.com
Web site: http://www.kodak.com/go/motion
I will now adjust it downward to 30psi now that I've read your input.
Thanks.
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And, hey! Let's be careful out there.
~Manny.
The McMaster-Carr catalog has some good overview text about how you're supposed to build together compressed air systems, along with this nice diagram:
But yes, the quotation for what they're installing includes a filter and a regulator...
--jhawk
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