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Lance and Ted, I'll add to what CNKS said. I used to use a 2hp (true hp), 6.3 cfm@90 psig, 20 gal tank single stage compressor for painting cars years ago. Despite what most will tell you, that can be made to work - but - you have to want to do it very bad and you have to make a number of compromises in paint, equipment and procedure. Plus it's brutally hard on the compressor and it increases the problem of moisture contamination. I would not recommend something that small to anyone for most regular sized spray guns. If you are talking a full sized spray gun, I think you should have up in the 10 cfm area at least - unless you are willing to paint cars a panel at a time. Panel-painting is not a good idea with metallic paints. Even with 10 cfm, you have to carefully select the gun for capacity requirements. Many require more than this and therefore would only be good for panel-painting. You must be able to complete the first coat on a part before the air pressure at the gun drops below the minimum. It can happen fast. If you use a gun that has a capacity rating (at any inlet pressure) less than your compressor rating at 90 psig, then you are always in a race against time to complete a first coat such that you can take a break for the compressor to recover. I am now using a 2 stage compressor rated at 17 cfm@175psig with an 80 gal tank. It will keep up with most (but not all) full sized guns continuously. The situation can be a little different as far as painting tractors, instead of cars, goes. For most tractors without large individual parts, a spot gun can be utilized quite effectively. Even an entire chassis can be done that way since areas like the final drives, engine block, transmission, etc can be masked off and done one piece at a time, even if assembled. I know it's a pain but it is a way to proceed. I have done all the sheetmetal on my '42 AC-B using only a spot gun - even the hood. That gun (DeVilbiss SRI) requires 4.8 cfm and can be used easily with the smaller compressors, even for lengthy periods. The issue you have in that case is to be able to complete a single coat on a part within the gun cup paint capacity - for my gun it's 4 oz. You don't absolutely have to do this but I don't like to stop midcoat to refill paint, even if it is already mixed. It's a fairly expensive gun but has a relatively large pattern for a spot gun - claimed to be 6" but I put at 5" maximum. If you were painting for profit this would not be the way to go. Most would frown on it, especially the car painters. However, I disagree and for the individual with limited compressor capacity and time to do things piecemeal with a tractor, it can be a very acceptable course of action. I wouldn't recommend it for car parts since the areas of door panels, hoods etc, are relatively large and broad. They do not lend themselves to area reduction by masking - you really need the larger pattern of a full sized gun for such parts. As far as sandblasting goes, you really want lots of air. If you are less than 10 cfm, you can only do small parts or just spot areas and it takes a long time. You will tire of that very quickly for anything of significant size. Even my 17 cfm compressor can barely keep up with my 1/8" nozzle pressure pot blaster. I wouldn't attack an entire tractor with that - it would take me days. I can do an individual fender with it but it still takes a while. Sandblasting is an area where more is better as far as air goes.  Rod
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