Air Quality for spray painting

[Troll Hunter]

I thought I'd post up my attempt at getting reasonable quality air for my novice spray painting programme. I'm approaching the rebuild stage of the total strip down and rebuild of my 110 CSW, and with all the panels removed, and available to be prepped and painted separately, I've turned my attention to trying to get reasonable quality air. As far as I can gather, entrained oil from the compressor and water condensation from the compressed air are the main contaminants that degrade spray painting results, so I have attempted to address both of these problems. I've had a gasoline powered compressor for a few years, and am very pleased with it. I decided that I needed a means to remove water from the compressed air and I needed to be sure that I had an adequate air reservoir. From these basic criteria I came up with the following design.

Air from the compressor passes through a 3/8" hose initially to a small entrained oil filter and then through the recycled evaporator unit from my LR A/C system. This is cooled by a 12 volt fan, also from the original A/C system. On the outlet of the cooler is a water KO pot with drain. Air then passes into the accumulator, which is a recycled 100lb propane cylinder rescued from our local dump. This ensures that I always have adequate air pressure even if my instantaneous demand exceeds the compressor capacity. My final air polishing is via a 36" long desiccator filled with desiccant pellets. This feeds my spray gun, via a 1/2" hose, which has an air pressure controller mounted immediately upstream.

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The photo above shows the air inlet from the compressor and the oil filter. The water KO pot is shown right of centre with a drain valve at the bottom.

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The water KO pot is more visible above.

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The photo above shows the reservoir outlet and the desiccator. The top outlet feeds the pressure controller at the spray gun.

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The final business end, what all the effort is intended to support.

I've hung the cooler/fan combo on wiresfrom the neck of the reservoir. This seemed the easiest way to allow me to get the cooler "horizontal" - more or less! This could be important since the air passages go back and forward five times between inlet and outlet, and I don't want to waterlog the system. The desiccator is also hung similarly. For safety, I pressure tested the whole system to ~200psi. I totally filled the system with water, flushing and venting until all the air was out, closed the valves at both ends, I had to install a temporary one on the inlet, and stood the reservoir in the sun for a couple of hours. As the water warmed, only slightly, so the pressure went up. I was chuffed that there wasn't a single leak in all those soldered and compression fittings.

So, I had a free reservoir, I already had both the cooler and the fan, and I spent about $50 on fittings and copper pipe. If I get reasonable quality air I'll be well pleased!

Before I start to use my Heath Robinson contraption, are there any other concerns or improvement suggestions I should incorporate?

Mike

Edit: Sorry for the lack of photos, but if the site doesn't support *.jpg, I hope you've got a good imagination! Or, you can go here:

https://forums.lr4x4.com/topic/102897-s ... -painting/

Mike