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Topic Review (Newest First)
09-04-2007 10:53 AM
oldred Exactly my point, the moisture is there be it vapor or liquid-it is there in whatever amount remained after it left the separator. You will have exactly the same amount of moisture exiting the gun regardless of whether it comes out of a cold hose or a hot one, the difference will be vapor or liquid. If it comes from a cold hose then a large percentage of the moisture will already be condensed into liquid water on the walls of the hose (this is why the separator needs to be AFTER the cooler since vapor will pass through most separators). Even at the colder temperature as the air expands upon exiting it will cool even more and cause more of the remaining vapor to condense into liquid, this will be in ADDITION to the liquid water being expelled that had already formed on the cold walls of the hose. If however the hose is kept warm, or better yet heated in the sun as you described, then the air will be hotter and the water will remain a vapor until it reaches the gun. All you will have to deal with at this point is whatever vapor condenses as it leaves the gun instead of having an already condensed liquid from a cold hose being dispersed with the air.
09-04-2007 10:30 AM
SuthnCustoms I agree totaly but what i was in fear of is IF there ANY moisture left in the hose itself at all,it would liquify when it hits the cool gun,been there and done that so many times,the gun actualy forms a "sweaty" film and drips while spraying,the humidity here in Ga is terrible
09-04-2007 10:23 AM
oldred You actually went backward in trying to insulate the hot hose, think about it. As long as the air is cold the water is in liquid form, exactly what you don't want, but if it is heated inside the hose it will then become a harmless vapor. (hot air hitting a cold hose would result in liquid water, cold air hitting a hot hose would result in vapor) I know this is the opposite of what we all have been saying forever about cooling the air to remove moisture but remember this is after the separator so now you are stuck with whatever moisture remains in the air in the line so you would be far better off to keep it hot so the moisture would stay in a vapor form. Some of the vapor will condense upon exiting whatever tool is being used at the time but this is still preferable to having the vapor already condensed into liquid on the walls of a cool air hose. I guess my point is that the goal should be to cool the air as much as possible BEFORE it enters the separator so that moisture can be more efficiently removed. But AFTER it exits the separator the remaining moisture is only going to be removed when it exits the hose through whatever tool is being used so at that point hotter air would be preferable in order to keep as much of the remaining water in vapor form as possible.
09-04-2007 09:35 AM
SuthnCustoms You'd be surprised at how much moisture the first trap caught right off the compressor.
I mainly wanted the first one to catch any contaminants (oil,dirt,dust etc) before it went any further in the line but it collected ALOT of water in it also.

Mind me,this was ALL a "redneck" makeshift backyard setup just to get the job done on a few vehicles.
I had an old shed type shop big enough to put a car in and build a makeshift booth.
The shed was 100 foot or so away from the house with no power so, i had to run hoses from the compressor behind the house where 220v is available, so i had 150ft of hose to the shed.

I had the first trap right off the compressor,ran the first hose in a downward circular motion around an old wire fence tomato steak,then to the second trap on the ground below the AC evaporator,then another trap below the exit side of the evaporator and to the gun in the shed.
We came across the idea of using the evaporator in ice but was kind of in fear the last part of the hose laying in the hot sun outside would cause alot more moisture in the line with all that cold air suddenly hitting the hot hose,so long story short we just ran the last part of the hose through some old 2" PVC pipe to keep the hot sun off it and go with that.

It worked WELL,so well i had everything on quick disconnects and only used that whole setup for painting untill i got a better setup to keep moisture and contaminates out of those lines while using air tools.

heard enough of the old"Redneck Engineering" ?
09-04-2007 06:15 AM
redsdad When it is time to paint, I intend to try the washtub and copper coil in ice water followed by a water trap. But I also might add a cooler between the compressor pump and the tank. Besides causing more water to "drop out" in the tank, you get "more" air in the tank this way.
09-04-2007 05:56 AM
oldred The A/C core has been used a lot, nothing new here, and I know of one (made from a core from a ranger PU) that works really good and this guy had a real problem before due to poor line layout, he still has a bad setup on his lines but the A/C core takes care of the problem. The twist here is in using an Air conditioner to cool the core instead of just a fan and it sounds like it might work really well. If the cool air from the A/C unit is channeled into the core and then a GOOD water separator is used it should take care of most moisture problems even with very short lines, maybe not work as well as a dedicated drier unit but I would think it should do pretty good.

Two of your driers would work a lot better on the down stream side of the cooler since the two before the cooler are in warm air where the moisture is still in vapor form.
09-03-2007 09:37 PM
SuthnCustoms Alot of guys have used the AC evaporators and they work well,just have to make sure the connections handle the PSI.

I used one from an old 86 F250( thing was HUGE) diesel for painting before i bought an air dryer unit,i didnt put it in ice,just a good fan blowing through it and have had to bypass it to use air tools because it dryed them out too fast it worked so well.
But i also had a water trap in 3 places,right off the compressor,down low right before the evaporator and after it and then a cheap dessicant disposible before the gun
09-03-2007 05:13 PM
oldred When you get this thing put together come back and tell us how well it works, you may be on to something there.
09-03-2007 02:52 PM
Air Dryer

I agree with you on the AC evaporator coil a large one. A roll or two of aluminum metal tape to seal things up so all the cool air flows thru the coil a water trap and you have dry air. Where there's a will there's a way! TF
09-03-2007 02:05 PM
oldred Jag, I too have used that trick it really does work and works well. The large A/C evaporator core and A/C unit would work on the same principle by cooling the air before the separator but not as well as the ice water. The A/C setup would be a permanent solution if it worked good enough for his application but then an A/C evaporator core with a simple fan forced air flow through it works pretty good too.
09-03-2007 10:49 AM
Air Dryer

We did a T-bird using a larger plastic tubb filled with ice and about 30 feet of 1/2 inch copper tubbing. You still have to have a water seperator at the end of it. But the rube goldburg dryer worked for a one time shot. The tubing is emersed in the ice-water mix (about 70-90 lbs.). The seperator worked great in removing the water with a constant blowdown removing the water.

If you are looking for a permant fix go looking for a regular air dryer. Used ones can be had off of ebay. Good luck TF
09-03-2007 10:27 AM
oldred Basically that's how the commercial drier units work so the idea is sound but I doubt it would be very efficient. Maybe if the air conditioner was big enough and you could box in the core so that all the air from the compressor had to flow past the cooler core but remember it would be under high pressure so I doubt seriously this could be done safely even if the multitude of other problems could be solved. IMO this would be far too impractical but I have to admit it is an interesting idea. A heat exchanger such as a larger auto air conditioner evaporator with the compressed air flowing through it and placed in the air flow from a large high output air conditioner unit would cool the air substantially and would make a water separator work very efficiently. If this separator were to be located just after the air exits the evaporator core while it is still very cool then I would think that most of the moisture would be removed. Not exactly converting and air conditioner to a drier but it would use the AC to make a standard separator work much better.
09-03-2007 06:38 AM
Air dryer

Is it possible to turn an air conditioner into an air dryer for an air compressor.

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