Painting a garden tractor

A single stage paint is one that provides both the color and the gloss in a single step. It is what most people think of in a paint. A two stage paint is typically used on modern automobiles where the color is applied as a first step (after a primer). This color coat (also called a basecoat) is not very glossy at all. The gloss is achieved by application of a separate clear coat on top of the color basecoat. A 2K paint is not the same as a two stage paint. The 2K really means a two component product. By convention, reducers added to a paint to thin it are not considered a separate component. The second component in a 2K paint is typically a hardener additive. Enamels usually can be either 1K (no additional hardener additive used) or 2K (if a hardener additive is used). Unlike enamels, urethanes require a hardener, sometimes also called an activator, and are therefore always a 2K product - as far as I know. A surfacer is a heavily bodied, easily sanded, product that is used to fill in sandscratches and very minor imperfections prior to applying the color coat. It is usually applied in addition to and over a bare metal primer such as an epoxy or etching primer. It has been my experience that for surfaces that have only been sandblasted and where two coats of epoxy primer are used and applied smoothly, that no surfacer is necessary prior to the color coat.

With the single exception (afaik) of a two part epoxy, all 2K products (enamels with hardeners and urethanes) have isocyanates in the second component additives. They therefore should only be used when a fresh air respirator system is available. Automotive type clear coats are almost always a 2K urethane product.

A sealer is used to "seal" an underlying paint film and avoid possible compatibility problems with whatever is applied on top of it. A sealer can also be used to provide a uniform shade of a multishaded surface prior to applying a top color coat. An epoxy primer can also be used as a sealer in most cases. If you are going to be taking surfaces to bare metal and using compatible paint products, there really is no need for anything called a sealer.

Typically you would apply at least two and preferably three coats of color using a single stage paint. If it were a basecoat/clearcoat (two stage paint system) you probably would apply two or three coats of the color basecoat and then apply two or three additional coats of clear over that.

A 1.7mm tip is really a little large for the majority of painting, assuming your gun is a gravity feed hvlp. A 1.5 tip would be more "universal" in nature except for those more heavily bodied surfacers, where the 1.7 or 1.8 would come in handy. If you are not doing a lot of surfacer work, you certainly can get by with a smaller than otherwise recommended tip for the surfacer. The application may take longer that way and the surface not as smooth, but the surfacer is going to have to be sanded anyway, no matter.

You can paint successfully down to about 60F but I really don't like to paint below 70F. Some people will push it down into the 50's but I wouldn't recommend it.

In an open door garage, you really need to have a significant amount of forced ventilation provided. You'll be surprised how fast the overspray and fumes can build up for any but small pieces in large rooms. No open heaters during spraying or until all fumes are removed. Too high a risk in my opinion.

If you using DuPont NASON, be sure you get the technical data sheets for all the products you are thinking if using. Unlike most enamels, the NASON Ful-Cryl (I think) acrylic enamel actually requires a hardener additive in order to dry properly. With other typical acrylic enamels, the use of a hardener is optional. The only NASON acrylic enamel that can be used w/o a hardener is their "Fast-Dry" acrylic enamel. You can get all the details from DuPont's website. If you need help in navigating to the NASON section, post back.

Rod

If your sheet metal is pitted, it all depends on the depth of the pits whether a surfacer will take care of it with a reasonable number of coats. If they are deep enough, you may want to consider a two-part finishing putty in addition to the surfacer. You can see how I dealt with pitting that really was too deep for a normal surfacer application by reviewing the photos of my AC-B fender painting here.

The 1.4mm tip on your SATA is smaller than normally recommended for applying a surfacer product. However, as long as you are not doing a lot of work with it, it will do OK. You will not be able to achieve a full pattern size because of the reduced paint flow (in oz/min) through the smaller tip with that increased viscosity. As long as you are not that concerned with speed, go for it. You're going to sand the surfacer anyway so it really doesn't have to be as smooth either. I have run surfacer through my DeVilbiss spot gun with a 1.0mm tip. It works - just slower and takes more passes than it otherwise would. If you have a lot of surfacer work to be done at the same time - like an entire car - you would be better off replacing the tip and needle assembly with something more like a 1.8mm just for the surfacer, in order to get the best performance out of your gun. But otherwise, I don't think it is absolutely necessary.

Your touch up gun should work fine for single stage color as well as the OMNI epoxy. As you see in the photos, a spot gun with a 1.0mm tip is what I used for my AC-B fender (including the surfacer - MP182). I also used the same gun for the hood, which is the largest single piece of sheetmetal on my B (with surfacer there too).

Rod