Acetone for paint thinner

Acetone is becoming more and more prevalent as a paint thinner or thinner component because of increased air emission regulations (VOCs). It is a solvent that is exempt from regulations. Don't ask me why it's exempt. I'd like to know myself. Rustoleum products used to have their own proprietary "thinning oils" and cautioned not to use anything else. I am not a fan of Rustoleum for spraying so I have no experience in "experimenting" with it. The best I can recommend is to follow the label instructions. Anything else is somewhat of a crap shoot unless you can find someone else who has done successfull experimenting with the exact same components.

Acetone is a fast evaporating solvent so you might try uping it to the recommended maximum 15% ratio. Also review this regarding orange peel, courtesy of Martin Senour:

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ORANGE PEEL
( Poor Flow, Texture)
Paint film having an uneven texture that resembles the skin of an orange.

CAUSE
(A) Under reduction and/or air pressure too low.
(B) Thinner/reducer evaporates too fast for spray conditions.
(C) Excessive film thickness or piling on of heavy wet coats.
(D) Improper spray gun set-up.
(E) Improper painting technique.

REPAIR
(1) Compound or polish to reduce surface texture.
(2) Or, sand smooth with 1200 or finer grit sandpaper, compound and polish to restore gloss.
(3) Or, sand smooth and refinish.

PREVENTION
(A) Use proper reduction ratio and spray at recommended air pressure.
(B) Select recommended thinner/reducer based on temperature, humidity, air movement, and size of repair.
(C) Avoid heavy coats and excessive film thickness.
(D) Use recommended spray gun, fluid tip and air cap for the material being sprayed. Always adjust the gun for best atomization and balanced spray pattern before paint application.
(E) During paint application, hold the gun perpendicular and parallel to the surface. Adjust speed of pass, pattern overlap, and distance from the panel to achieve the desired appearance.

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Be sure to check the air pressure directly at the inlet to your gun. Install a pressure gage right at the inlet as shown below and check the pressure with the trigger pulled. Make sure the fan pattern adjustment screw is wide open and the fluid control adjustment screw is also wide open. There does not have to be any paint in the gun to do this. Set the pressure using whatever regulator you have back at your compressor. Never mind the pressure at the regulator. It's the pressure right at the gun inlet that counts. An HVLP gun should have the "maximum" pressure indicated on the handle or in the instructions that came with it. It typically will be about 30 psig but could be anything from 15 to 50 psig. Set the pressure at least to that number. If that doesn't do the trick try going 5 or 10 psig higher (if you are not regulated by some law in your area) to get a little better atomization.

If you still can't get it to work well, I'd look at using a different paint.

Rod

Good for you. The absolute best way to learn and get confidence in spray painting is to PRACTICE. It is the rare individual that can turn out good work the first time, no matter the cost of equipment equipment or the brand, quality or cost of the paint. I think there are as many "opinions" and "preferences" as there are painters so take what you hear verbally with that in mind, even from pros. The best source of information is the written technical data sheets from the manufacturer of each product. There is more information on mixing, compatibility and usage in those sheets than is usually indicated on the can labels. The larger automotive paint manufacturers have pretty good web sites where you can download such information.

If you decide to move up from the Rustoleum, I suggest you look at some of the automotive paints that are available. Each manufacturer usually has two or more product lines of quality/cost products. DuPont has their high end line(s) and their economy line known as NASON. PPG has their own high end and an economy line known as OMNI. Martin Senour (NAPA) also has different lines but I am not familiar with them. I recommend you try out an acrylic enamel in the economy line of either NASON or OMNI. In NASON, it's called "Fast Dry". In OMNI, it's called "MAE". Here's a data sheet for the Fast Dry and here's one for the MAE. If you want to spend more money, try out Centari in DuPont or Delstar in PPG (if it is available in your area). They are the better acrylic enamels but pricey for what they are nowadays.

The acrylic enamels are a little more resistant to premature fading than the alkyd (or synthetic) enamels common in hardware stores and "tractor paint" outlets. I could recommend higher performance products (urethane or hardened acrylic enamel) than the unhardened acrylic enamel but I suspect you do not have the proper breathing equipment ($400 minimum) to safely use them. The best primer is a two part automotive epoxy such as PPG's OMNI MP170. Here's a data sheet. It is a two part product but can safely be used with a simple cartridge mask. The appropriate thinner (called reducer in this case) and mix ratio will be spelled out on the can label or the data sheet. There are usually several different ones to use, depending on temperature at the time of spraying. Stick with the exact proprietary reducer that is specified by the manufacturer of the paint. Don't mix and match - that is a potential for unforseen problems. And don't try to paint below about 60 deg F. Wait until it gets warmer.

Rod