I’m starting to weather rolling stock and I have a question about clearcoat selection for a particular case: On a couple of cars, I built up chalk weathering in layers, setting each layer with hairspray. The results have been pleasing, except for the facts that I don’t regard hairspray as a permanent solution, and that it leaves a glossy surface. What caused me alarm was, when I went to add a chalk layer over an existing layer set with hair spray (using a brush dipped in 70% alcohol), it broke down the dried hair spray and nessed up the underlying layer. I had planned on using Testors clear flat laquer, but now this has me worried. Should I look for a water-based clear flat? Shellac? (although that is alcohol-based) Something else? I decided to eschew using a clear flat between coats due to ventilation/weather limitations. The hair spray , I can do small spritzes in my bonus room. I was also concerned about too many layers of clearcoat obscuring detail. If hair spray under clear coat is a non-starter, the nice thing about the chalk/hairspray combination is that it comes off with soap and water, and I don’t have a lot of time invested in the small number of cars I’ve done.
I suspect the second coat partially dissolves the first, but if you just spray it on instead of brushing, nothing runs. However, don't use anything alcohol-based over the Dull Coat; it creates a white haze. You can make a faded paint effect using that technique but its hard to get it even.
I don 't know of any clear coat that will work over hairspray. But, sans that, I would try out some Krylon, or similar, dull coat on the inside of a car. That would ascertain wether or not it reacts with the paint or plastic. Then spray it over the chalk, from as far back as you can and get a good coat.
Gotcha. Right now, it’s not the dull coat I’m worried about spraying over, it’s the hair spray. The ability to start over completey with a soap & water treatment, when using hair spray between coats is too much to give up. (Right now, anyway.) But maybe a hardier intermediate clearcoat is in order - I can apply a chalk layer for paint fading wetbrushed with 70% alcohol, but I can’t come back to do a mud splash layer over it the same way, not even just in water. That chalk layer has to be brushed on dry. A proper clear flat intermediate coat might let me get away with a chalk-in-water technique on second/third/etc. coats. I guess it’s time to bite the bullet and spray clearcoat on one of these early cars and see what happens.
Hmm. I use powders dry and carefully put stuff in place. Here's a video of how I did one car, I have not, and do not plan to, clear coat them. I have found that the powder I use seems to just stick very well.
I found that things like chalk and pan pastels work a lot better if you dull coat the car beforehand.
Anyone try Krylon Fusion paint and clear coat? I believe it comes in a matte finish as well as gloss. Krylon claims it is safe to use on plastics.