The powder coating that I’ve done requires the powder to be applied, then it needs to go into an oven for a while to “flow out” (change from the powdery appearance to a liquidy appearance) then it needs to continue baking to cure. Almost everything from Eastwood (everything I’ve seen, except the clear powders) needs to bake at 450º F to flow out and then continue baking for 20 minutes at 400º to cure. Powders from other companies need different flow out/cure temps/times.
I attempted to change some powder coat from powder to liquid using my laser cutter. The results were pretty bad (not nearly as good as the results achieved by the person that @smcgathyfay linked to). The powder just pilled up and burned without adhering much at all. I was trying to coat aluminum though, maybe the reflective nature of the aluminum makes it trickier. Also, I tried it shortly after getting my laser cutter so maybe I made a rookie mistake or something. I also tried burning off cured powder coat, but that didn’t really work either. My laser is 30 watts, so maybe it didn’t have the necessary power. Also possible is that once the cured powder got thin enough that it became transparent, the aluminum underneath just reflected the laser away, preventing it from heating up enough to vaporize.
Toner is an interesting idea. It’s designed to cure very quickly so might work a lot better.