Usually the compressor will have the specs printed on a label or plate. If it doesn't have anything like that, do you know how many HP the compressor's motor is rated at? If it's less than 5hp, it probably won't meet the minimum for a typical HVLP spray gun. 

I would say the absolute minimum for painting a car is 2-3 HP compressor with a 20 gallon tank, and that's marginal. If it's a two-stage compressor (rare for a smaller one) that helps a lot. If you go for a low-flow gun like the Eastwood types I mentioned, it could work. It will just be slower because those guns won't cover as much area in one pass due to the lower air flow.

With the cost of automotive paint being what it is, I'd experiment with some cheaper paint first, seeing if you can lay down a smooth non-pebbly finish. (maybe you can get some leftovers from the paint shop for experimentation.) If it works out, then try painting the Mini, maybe do the subframes first, then try the interior or inside of the bonnet, and work your way to the exterior panels to make sure things are working well.

An air-supplied respirator is ideal - if the paint you are spraying has isocyanates (usually present in the higher-quality paint lines) it is essential to have an air supplied respirator. Isocyanates are the most lethal of the automotive paint additives, and are odorless. A quality cartridge respirator can filter isocyanates - for a while. The problem is that you can't tell when the cartridge is no longer effective, and when that happens the isocyanates will leak through.

Isocyanate damage is cumulative - you might get away with breathing the fumes a couple times, but it builds up and then suddenly you become sensitized to it and even tiny exposure causes breathing problems and allergic reactions (not to speak of worse medical problems later.) This happened to me - now, if an isocyanate paint mixture even touches my skin (like some spilled on my clothes and seeping to the skin) I get a burn-like reaction. Think of what would happen to the inside of my lungs...

So if you don't want to go with an air-supplied respirator, avoid isocyanate paints and clear coats. IMHO if you're really serious about painting cars, you should have one. Once you see the price of a gallon of decent automotive paint, it's not that expensive an investment. (BTW that's another subject - auto paint prices from the big names have gone through the roof in the last 10 years - triple what it was at least...)

Blue, thank you for your comprehensive list. I do have a 3M respirator, which use for rattle can spraying. Do I need a fresh air supplied respirator?
I do have a small compressor, how do I tell if it can maintain the 90 PSI and 9cfm? Jim

My advice is to buy the best compressor you can afford. To run a good finsh spray gun (HVLP these days) you need plenty of air flow - otherwise you'll have to watch the air pressure and stop when it drops off if your compressor is too small.

If you need a portable compressor it makes your options limited. A unit good for painting cars (even a Mini-sized one) usually runs on 220v. Hopefully you can bring your sculptures into the paint booth so you can use a larger 220v compressor, if possible 9-10CFM @90psi or greater (greater is better.) A 14 CFM unit keeps up with almost any spray gun. 

Try not to use long extension cords for power - use the shortest cord you can and run longer air hoses instead.

Eastwood sells some low-CFM guns which are said to work OK, if you're compressor-limited.

As for the guns, the primer gun need not be anything terribly expensive - you just need a large tip to spray the viscous primers (1.8mm usually.) Some of the Harbor Freight guns or the inexpensive DeVillbis Startingline guns will do the job fine. 

For the finish gun, remember that practice and technique is by far the most important factor in getting a good finish. A novice painter will probably get the same finish from a $100USD gun as they would from a $700USD unit. The more expensive gun will probably last longer and have better support (caps, needles, spare parts, etc.) which is what professionals need.

Once you get some experience you may see where a more expensive gun can be of help. Sometimes buying the more expensive gun can be a detriment to a novice if it has too many adjustments and options.

The other items to think about are 1) a good at the gun pressure regulator so you can set the spray pressure accurately 2) if you live in a humid climate you probably will need something to take moisture out of the air supply, and it's a good thing to have no matter the climate 3) good hoses, at least 3/8" in diameter or larger - don't use 1/4" hose.

And most importantly, invest in good respiratory protection for your lungs. If you can't or don't want to get a good respirator don't bother with self-painting, it's not worth it.

You painters, I'm going to jump into the paint finishing scene. I don't much about it. Watching YouTube videos.
I will be paint a few minis and my outdoor sculptures. Will need a primer gun and a finish gun & compressor.

What are your recommendations and likes? Thanks Jim, [email protected] 631 566 4989