Painting tricks

[Anticept]

I was taught to paint by a person who painted cars for a living. If you want to fix that paint job and the defects, here's how. You might want to practice on something else first, obviously.

The type of paint used in CTs are an acrylic urethane. Acrylic makes the shine, the urethane part protects against UV radiation. PPG Concept is the stuff I use. To spray, it's a 3 part. Paint, hardener, and reducer. The reducer is only required when spraying, don't use it for touch ups.

First, fill and glaze the site as necessary. Filler is body filler, a thick paste. You can use a microballoon mix or an actual body shop filler. Rarely needed, used to fill areas that glaze would seep out of, otherwise skip this. If used, fill to the surface then sand down below slightly, starting with 40-80 grit  finishing with 150-200 grit. You will use body glaze on top and we need the rough surface to help the bonding.

The body glaze is a very thin body filler like compound, but flows so much easier. THIS IS IMPORTANT. I have ALWAYS topped off composite with body glaze, the results have always been substantially better than just using body filler. USC Icing is HIGHLY recommended, best stuff I have ever used and makes leveling the surface easy. Apply it with a flat plastic applicator. Apply it so it feathers into the nearby paint. When sanding, do not remove the feathering, this is important for that smooth transition. Some of it may go away on its own, that's fine, but don't make an effort to remove it. Start with 300 grit or so to rough sand, then 500 for smoothing. This is the part you will need to spend the most time on getting it right, because imperfections WILL SHOW when you paint. You can use higher grits if you want for even smoother. Wait an hour or two for the filler and glaze to really set.

Great three part series on fillers:

 

Note on part 3: ignore the epoxy part, we're not using epoxies used in cars, it's different.

 

Generally speaking, primer won't be needed when working with an acrylic urethane. It will bond nicely to the body glaze and previous paint layers quite well.

Next, prepare environment conditions according to paint instructions. Wash an area 3 times larger than the repair site with very mild soap and water, then mask off.

Put on respirator, mix the paint, then spray a tack coat. A tack coat (or dust coat) is where you hold the paint gun a lot further away than normal, and do a quick sweep across the surface, leaving a heavy dust like coating. Let sit for a few minutes. This helps keep paint from running.

Next, the main phase of painting. We need to aim for paint blending. Don't EVER paint all the way to the edge of the masking or it will cause a very pronounced paint line.

The first coat is centered mostly on the repair area and RAPIDLY feathers out to dust coatings as you work out, and you should stop spraying before reaching the masked area. Now the technique for this will be HEAVILY dependent on the type of paint gun you are using. If you have a paint gun that engages air before allowing paint into the stream, then congrats, this will be easy, because you don't have to worry about the paint gun spitting out splotches of paint as soon as you pull the trigger. You might even be able to control paint flow depending on how hard you pull the trigger.

When painting, you're going to quickly move the gun from one feathered edge, to slowly moving the gun where you are laying a coat, back up to quickly moving the other feathered edge, in a smooth motion. Or if your paint gun supports it, press the trigger harder and let up easy. The idea is you want the heavy coat in the center, and a feathering along the edges.

To illustrate the point, If you were to use two different colors, the feathering would look something like this upon very close inspection (white coat under, dark coat on top).

 

With each paint layer, follow the paint's instructions on time between coats. Each time you lay a new coat, you're going to work the feathering further away from the repair area. Generally you only need two, maybe three coats. Again, you should not be dusting the edge of the masking! You want a nice gradient. People more skilled than I am won't have to do this "working outwards", but I'm not *that* good yet.

Once finished, let the paint set according to the instructions. Maybe let it sit a day. Come back, and start sanding with something around 1000 grit. You'll have to just learn what calls for what on your own. Move to 1500, then 2000. By now it's going to be pretty smooth if you've done it right. For most people, you can stop here. Let it dry and look at it.

If you REALLY want it to shine, you will need rubbing and polishing compounds. However, you will not get a shine like a car, we're not using a pure acrylic. The urethane part does dull the shine a little bit and there is nothing you can do about that. In addition, if you make this look TOO good, then the rest of the plane will look like crap.