Originally posted by Robcolo
...Most air from compressors is pretty dry. The process of compressing it removes most all of the moisture [like wringing out a towel] and most compressors have a centrifugal separator to remove the rest.
GO ahead and air it up ! Those small 12v compressors pass the moisture right on through so maybe wait for a low humidity day.
Rob, not meaning to flame you, but your statements are completely false and without facts. You obviously have deduced these things on your own...perhaps when you make a statement like this you should maybe look into some factual information to see if maybe what you are saying isnt complete drivel.
This issue is something I have a fair amount of experience with, so I will offer some of what I have learned.
First of all, when moisture (water) is in the vapor form, it is relatively harmless to nearly all pneumatic applications. However when this vapor changes to a liquid state, it can wreak havoc on nearly ALL pneumatic applications.
There is a fine line between vapor and liquid, this line would be called the Dew Point. The dew point is when vaporized water will condense to a liquid state.
Atmospheric air at 75degF and 75% relative humidity will contain one pound of water per 1000 cu. ft.
At 100psi. line pressure, free atmosphere is compressed as a ratio of 8:1 and 1000 cubic feet of free atmosphere will then become 125 cu. ft.
The 125 ft. of compressed air, at 100psi, will contain ALL of the contaminants of the 1000 cu ft. of free atmosphere inlcuding the one pound of water vapor.
Due to the heat of compression, nearly all of the water contamination will remain in vapor form immdiately after the point of compression. However when the due point is reached, all of this water vapor condenses and will be liquid contamination.
Just for an example of how much water can be produced with a compressor:
At 75degF and 75% relative humidity and 125cfm at 100psi, the potential of water content of the compressed air lines is 125cfm=1 pound of water/minute, 60 pounds of water per hour, 1440 pounds of water per day, 10,000 pounds of water per week,or 1,210 gallons per week.
Normal shop compressors will not create the example CFM, but it gives you a good example of how much water can potentially be in your air lines.
If you do have an air compressor then you know that the reciever tank will and does collect water. The collection is intially in vapor form, but due to the condition of dew point, the water condenses to a liquid state inside your compressor tank. Just open your drain at the bottom of the tank and you will see the result. BUT, this is not all the water that was in the air. Much of it still remains in the air that has exited the tank.
Not only does the air provide contamination water to your compressed air, it also causes oxidation of the tank and line metal introducing another contaminate to deal with...iron oxide.
With filtering of the compressed air, some of the moisture can be removed at the point of use. Also some of the solid cantaminate can be removed. However, with normal filters on the market, complete removal of the water is not possible. Also, a normal air filter will cleanse the air down to a point of 40 microns solids. This means that if there is iron oxide, the filter will keep any particles of it from passing IF they are larger than 40 microns in size. This cleansing is fine for some applications, but when we are talking about seals and bladders, 40 microns just doesn't cut it. A particle of oxide as small as 10 microns can kill a seal fast. (40 microns is the smallest size of any particle that we can see with the eye...this is why filter mfg's just make filters that cleanse to 40 microns...out of sight, out of mind)
Also, normal filter rigs do not remove all of the water, in fact they remove very little water form the air. So the water contamination, as well as other contaminants, will remain in your shock even if you filter it with normal filters.
There is a solution to the problem though. If you use a filtering process called "Coalescense" virtually ALL of the moisture can be removed from the compressed air. Also with proper filtration, solid contaminants can be removed down to a point of .01 microns. Only when you have filtered your compressed air with proper filtration equipment should it ever be used in a shock.
Any particulate or water left in the air can damage seals, and the water can also cause catostophic problems when it freezes. Not to mention the vast varying the air in the shock will undergo with temp changes, due to the water content.
So, unless you have proper filtration equipment at the "point of use" then using compressed air for your shocks is a mistake. Although they won't show such a drastic problem as a bad filled shock will, tires aired up without proper filtration can change with the temperature due to the water content. That is why you can have a given psi in your tires in the morning, but when you check them later in the heat of the day, they will have changed. Proper filtration can eleviate this condition as well.
I have what it takes, but I don't want to SPAM, so PM me if you are interested.