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Homemade compressed air dryer

Champ

Champ

Well Known Member
Water has been my biggest problem when painting so I've been thinking about a home made refrigerant dryer - cheap. Has anyone converted an air conditioner or refrigerator to an air dryer? Perhaps the evaporator coil could be replaced with a copper coil wrapped around an air line. The biggest problem might be recharging the system. A little more elegant than a coil in a bucket of ice.
 
Maybe you don't need a full on dryer. My first air drop is after about 35' of 3/4" copper pipe, my spray booth is about 40' after that. I've never seen a hint of moisture in either. That copper pipe has a lot of wall area.
 
I have had very good luck with Motor Guard compressed air water filters. It made a huge difference in the quality of my paint jobs.They're less than $100.

I live in the desert, but they were recommended to me by Randy Lervold who lives in the Pacific NW.

Guy
 
Good ideas. It's great to have alternatives to solve a problem. Thanks for the input. I have to repipe my shop for a better paint booth for exterior paint anyway. May still look into a refrigerant system as well - just for fun.
 
I've always wondered if you could use an old water cooler for this. They have a holding tank where the water stays pretty cold. I was thinking you could run copper tubing in there all coiled up. I'm not sure if that little refrigeration unit could keep up with the heat a compressor puts out though. On the plus side, they are relatively cheap.
 
Usually the reason for very much water at the gun is because the compressor tank has gotten hot and did not condense in the tank and at the discharge water trap. Is this happening to you? A box fan will do a world of good if it is. I have a sand/bead blast cabinet indoors and it will suffer from water entrainment

Also, an automatic drain will help drain the tank. I had all these issues when I used a 30 gal tank with a high speed compressor that made a lot of heat. My current 60 gal with 2 stage pump delays the issues but if it gets hot, I get the same problem. What equipment are you using?

After a cool tank, then you can apply the other cooling and separation techniques including desiccant at the paint gun.
 
I recently moth balled my 3 hp/20 gal, & put in a 5 hp/60 gal/2 stage with massive cooling fins (between & after stages). It turns slow like a big old John Deere. Got a real deal on a used industrial unit. It may go along way in curing my water problems. I'll also add overhead pipe to the booth sloped back to the tank with drip legs. More filtration, dessicant or refrigeration can also be added if necessary.

Hope to be painting the exterior by fall when it will also be less humid.
 
My setup is much like Dennis's. I have an inexpensive (but good sized) water separator filter *at* my paint booth. This catches any water which has condensed enroute from the tank (as SCard describes).

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... and as Bill says in the next post, I use a little "ball" filter at the gun.
 
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Champ said:
I recently moth balled my 3 hp/20 gal, & put in a 5 hp/60 gal/2 stage with massive cooling fins (between & after stages). It turns slow like a big old John Deere. Got a real deal on a used industrial unit. It may go along way in curing my water problems. I'll also add overhead pipe to the booth sloped back to the tank with drip legs. More filtration, dessicant or refrigeration can also be added if necessary.

Hope to be painting the exterior by fall when it will also be less humid.
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That should cure most (if not all) of your issues. If you are shooting water based paints then a desiccant at the paint gun will be the last step.
 
Run your air through a coil of copper tubing submerged in a 5 gallon bucket of cool water. It will condense a lot of water out of the air. Put a water trap downstream of the bucket and you'll remove all of that moisture.
 
A dedicated dryer/separator is certainly one way to go, but the standard shop air installation simply hangs enough metal pipe length to allow cooling. Here, in the background, you see 3/4" iron pipe in standard hangars with a few of the drops/traps. The last drop at the end is where I pull painting air or connect water-sensitive items. There is no water issue, ever.

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DanH said:
The last drop at the end is where I pull painting air or connect water-sensitive items. There is no water issue, ever.
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+1. I'm in the middle of painting (my first attempt - sure is a steep learning curve!) and have piping similar to Dan's. By the 5th drop where I get air for painting, I don't get any water.

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Before I moved my compressor to the garage and plumbed it to the shop using 50' of 3/4" type L copper pipe I had water problems during the spring rainy season.

My homemade dryer was constructed out of a 5 gallon bucket and a coil of copper tube. I put the coil (about 8 coils of 1/2 soft copper) with the air inlet entering the bucket at the bottom and a water separator at the exit near the top. Quick disconnects used on both inlet and outlet.

Fill the bucket with cold water and all water in the warm moist compressed air was condensed and trapped in the water separator. Some times I would throw a block of ice in the bucket as well.
 
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