I recently had to do a repair on the bottom of my Surftech Caddy SUP. The color is a gray and some years ago I bought a can of Surftech gray spray paint. I didn't match very well. I also fly RC gliders and they are carbon fiber or fiberglass too so the repair process is pretty similar. The problem is what kind of paint to use once the repair is done. I started digging into paint from all sorts of different sources. In this process, I realized how little I really knew about paint. I have looked at hobby paint, car paint, and boat paint. In the hobby world, Testors makes a pretty full line of both oil and water based paints. I have been using the oil based type on my planes and hand mixing to match colors. I also happen to have a Grex air brush so I have been spaying my repairs with that. The problem with Testors paints is that the only come in tiny 1/4 oz bottles.
For my SUP, I wanted to paint a bigger area so I starting hunting around for "oil-based enamels" in bigger cans but not huge cans. I found that Home Depot and Lowes no longer carry oil based enamels. Sherwin Williams does carry an oil based enamel for about $25 bucks a quart. They can also use their scanner to try to match a given color. I have not tried their sutff yet
For my board, this time I ended up using something called 1-Shot Lettering paint. They come in 4 oz cans for about $15. I bought a can of White and a can of Black and tried my best to mix them to get the right shade of gray. I ended up a tad too dark but not bad. 1-shot is pretty slow to dry which is problem for backyard operations like mine because bugs and stuff tend to land on your nice wet paint job. I don't know how well 1-shot will hold up under use but I will see as I start using that board again.
One problem I have run into is trying to find true bright white. I have a can of "white" spray paint that I bough at an Auto parts store. It looks white until you compare it to something that is really white like Testors White Gloss. The spray paint has a definite gray tint in comparison. The 1-shot white is also a tad gray which is disappointing.
Event though I used the 1-shot for my most recent repair, I have continued to research about various paints.
So my general question is what type of paint should I really be using or should I just use whatever and then coat that with clear epoxy?
I went into a West Marine to see what they had for boats:
Seems like Oil-based enamels (like the 1-shot or Testors) are more or less out. I assume but don't know that those are all actually some form of Alkyd-type paint. West Marine had 1-part poly Urethane and 2-part Polyurethane which I guess is pretty much what auto paint outlets like Finish Masters also have. I probably part to stay away from the 2-part type and even the 1-part stuff doesn't come in anything smaller than 1 quart cans. So it is expensive to get a few colors for mixing.
Yesterday I stumbled across System 3 WR-LPU which is a water based Polyuretane. It can be had in 4oz "sample size" direct from S3. It is technically a 2-part but can be used as a 1-part. The additive is refereed to as a "crosslinker". I searched Swaylocks for that stuff and did find a thread or two. Curious if others have tried it. The available colors do not look like bright true colors for mixing. I was surprised to see S3 claim it is as durable as solvent based products like Interlux Seabright.
So what type of paint do you all use for repairs? Do you leave paint as the final surface or coat over with epoxy?
Here is what I would consider my ideal paint product:
1. Whatever the formulation, it doesn't need a clear over coat.
2. Comes in various colors to allow mixing including a bright true white. So at least White Black yellow red and blue
3. Comes in reasonably small sizes like 4 oz.
4. Sprayable with my Grex