Paint day - 1 of 2

Apart from the compressor and spray gun, you are pretty much looking at it.

The spray gun is a Devilbiss GFG-670

The trick to working with any paint is to make sure it is thin enough that the gun will atomize the material but not so thin that the integrity of the coating is compromised.

While SW specifically states not to thin/reduce Acrolon more than 10% I have been running closer to 15% with no ill effects so far.

SW sells 1 qt mixing cups with ratios printed on the side. Those work well when mixing the hardener and thinner. Mix up about 3/4 of a quart of paint and hardener and then add thinner and when done the total is almost 1qt of paint. I went through about 2 quarts of paint painting the following:

30" mower deck. top and bottom
50" deck - top and bottom of deck and top and bottom of stiffening plate
old power brush including the brush guard.
plow drive
30" mower drive
a-frame for 50" deck
Two extended front guards for 30" mower - top and bottom
rear guard for 30" deck ( the wide one) inside and out.
Rotary plow dirt deflector/shield.
two long style 30" deck skids
A few misc small pieces

There was a fair amount of surface area involved. I would say that 2 quarts would do a 4 wheel tractor and have some left over.

The Devilbiss cup liners are great. They allow me to paint in any direction, even upside down with no paint spills. Makes cleanup a lot easier too.

Next week I will strip and repaint a new style cultivator, another 30" deck, a 50" deck or two, a steering sulky, and a snow plow or two for a 2 wheel tractor. Why paint the snow plow if I almost never see snow? It is just sitting there rusting and there is no point in letting it sit and rot away.

The better SW stores have a deal on respirators/filters. Buy the filters and they give you the respirator free. The respirator is actually pretty good. When painting I can smell nothing except clean air. There are a variety of filter types available. They don't have them out front. You have to ask about it.

One more note about the recipe and the paint.

The colorant system is "844" as indicated on the label. Not all stores have that. The "844" tinting system MUST be used with Acrolon. Use of the normal tinting system guarantees a finish failure. While SW will pay to have the paint removed and supply the paint to do the job again if the sales droid tints it with the wrong colorant system, avoiding a mess like that is preferable. The 844 system can be used with any paint but it is more difficult for the sales droid to deal with as it is a powder. Most times, there is only one person in a store qualified to operate that tinting system. That person is not a sales droid but more of a Coatings Engineer.

Acrolon requires that the colorant be added at 150% of "normal". That means that if a different paint is used like SHer-Kem, the amount of tint has to be reduced by 33%.

The various columns of the recipe are as follows:

ounces - 1/32 of an oz - 1/64 of an oz - 1/128 of an oz.

In short, more than enough granularity for any color. Literally billions of colors.

For a brilliant color like the Gravely Red/Orange, the base is a gloss "ultra-deep base". The ultra-deep base an almost a clear. It also means that it doesn't cover as well so priming is a must.

For Acrolon I am using "recoatable epoxy primer". Other primers are are available including some "zinc clad" primers. The zinc clad is a marine primer.

Some might feel that I am being excessive about the paint. The Acrolon is not cheap. It runs a bit over $100 per gallon. As hard and durable it is, I feel it costs less than rattle cans in the long run. Rattle can/Industrial enamel will last a couple of years before it starts looking bad with it wearing off, fading, and oxidizing. The Acrolon will last much longer especially under a mower deck where grass, dirt, and sand is constantly abrading the coating. How many times of stripping and repainting do I want to do over the next 15 years? Once is plenty.

Since it is a true paint and not a plastic coating (powder coat is a plastic), I believe it will have less of a tendency to spider-web rust underneath. I only see spinder-web or Lightning rust under powder coat. Lightning rust is invisible. It only shows up when the powder coating is being removed. In the picture below, I would see one small spot of rust about the size of a pencil eraser, but when I started to strip the powder coat off is when all of the rust tracks appeared. The tracks extended far from the original rust spot.



"Lightning" rust.

Richard-tx said:

The trick to working with any paint is to make sure it is thin enough that the gun will atomize the material but not so thin that the integrity of the coating is compromised.

Click to expand...

I don't recall Valspar Tractor Enamal giving the thinning ratio. What then?

Rust is so strange! What caused the "lightning" rust under powdercoat?
Bad prep? After sand blasting, humidity will cause immediate rusting.

LilysDad said:

I don't recall Valspar Tractor Enamal giving the thinning ratio. What then?

Rust is so strange! What caused the "lightning" rust under powdercoat?
Bad prep? After sand blasting, humidity will cause immediate rusting.

Click to expand...

I can't speak to Valspar enamel.

The lightning rust is not flash rust. It actually rusted the steel away leaving a measurable trench in the steel. Why does it happen with powder coatings? I am not sure. I think it has to do with the fact that powder coating is really a thermoplastic. I have not seen anything like that on painted surfaces.

I don't think it is due to poor prep. It seems to be a universal problem. It might have to do with the application process but that is a guess. The coating (and part) is heated after the powder is applied. The heat melts and flows the powder creating a nice shiny finish. The powder adheres to the surface electrostatically. Since heat is applied parts will expand and contract. It may just be the nature of the plastic to allow water and air to migrate under the surface.


Flash rust isn't bad. Steel or cast iron that has flash rust on it can be painted without issue. Rust is an oxidation process. Like any oxidation process, it requires oxygen, a fuel source, and heat. Since the heat is uncontrollable and the fuel source is uncontrollable (steel or iron), the only thing that can be controlled is the oxygen. A proper coating on the metal will keep the air (O2 and H2O) away from it preventing further oxidation.