I used to have a binks pressure pot that had a agitator driven by a air motor. Keeping the mix equally agitated is key as is spray direction, etc. the difference in vertical and horizontal surfaces can be noticeable. The weight of the metallic can cause it to drop or slide on vertical surfaces if your reducer selection and application technique isn’t dialed in. Base clear makes it easier... single stage, especially high solids, like acrylic enamel, are less forgiving.
I have had good results laying down a solid base color followed by metallic, then clear. That allows depth without multiple layers of metallics. This is helpful with colors like red that require numerous coats to become colorfast, it’s also a little cheaper. I’ve also experimented with various leftover mixes with different colors and sizes metallics, but it’s impossible to match if you don’t retain some for touch up. Painting is art, don’t fear it, just do some research and experiment till you achieve your desired result. I’m not sure of your experience level, but I learned to apply the base coat as a Matt finish, as opposed to trying to lay it out, as I would single stage or acrylic enamel, enamel, etc... if you just use the base to cover and achieve a uniform “base” color, the clear provides texture, or lack thereof, hopefully, and shine. I initially had difficulty switching from single stage to b/c because I tried to apply the base as I did with other types. Fortunately a long time friend was a automotive paint store manager and was sent to various factory training classes to support the gradual change to urethane and b/c products, so he was a helpful critic at the time. B/c is easier and allows for superior results, imho, because it is easier to repair, etc. Unfortunately supplies have become very pricey, so buying five or six chemicals after performing all body work and applying sealer adds up.
Good point on gun cup: siphon vs gravity feed. With siphon feed guns the paint is drawn from the bottom similar to gravity, but with gravity you get the high solids, heavy stuff first because it is drawn from the bottom like a funnel. When I paint, and it’s been longer than I care to admit, I am periodically twisting the gun side to side when not spraying to help mix, especially metallics. I also wrap a rag around the cup with tape or rubber band to absorb any paint that might escape through the vent or around the lid. (Prevention) The thing to remember is time. You aren’t going to have the mixed material in the gun that long. If you have to pause for any length of time, be cognizant to re- agitate. Consistent application, ie: direction, distance, speed, will be reflected in the finish. It’s really not all that difficult, just nuances to keep in mind. Buy a little extra and paint a old hood or door panel first to get a feel for it if you are concerned. Spraying a narrow part, such as a frame, may not give you the feel as a larger panel requires more care to achieve a uniform application. But don’t over think it, just be mindful.
