When spraying the flat finish from Alclad, a white powdery coat seems to settle in corners and crevices. Since the overall flat finish is otherwise great, how can I reduce the powdery overspray?

I checked the website for Alclad, but this issue isn't covered there.

Probably air pressure is too high. Dilute lack a little and lower the pressure.

Jim,
All the Alclad clear coats are designed to go on "wet", and dry fast. You need to be 6" or less from the surface you're applying it to, with a wide nozzle pattern on your AB. I usually start in corners and nooks and crannies before getting into larger areas. The "dusty" appearance you're experiencing is part of the clear coat drying just as it gets to the surface, then being blown into the corners. Try spraying it at a lower air pressure. I spray Alclad at 8-12 PSI. This keeps the solution "wet" longer as it's going on, and work closer to the surface. Occasionally, due to an obstruction, I'll get the "dusty effect" too. When I see this happening, I let it dry and use a Tamiya "buffing swab" (available at Hobby Lobby), to buff it out, then I recoat that spot from a different angle. If I continue to have a problem, I turn up the PSI and narrow the spray pattern, which has the effect of putting more of the coating into a smaller area. Hope this helps.
VR, Russ

Thanks guys. I'll let the current coat set for another hour, then re-apply as suggested. The bottle recommended 15-20 lbs pressure, which apparently is too high. My distance was already as recommended by the comments, so we'll see if the reduction in pressure helps.

Just another note-- I don't know what airbrush Alclad uses to recommend air pressure. But I've found airbrushes can vary in spray patterns and PSI recommendations. I use a Peak C5, a Badger 150, and a Paasche Millenium, and I've found they all behave differently when using Alclad-- some require more and some less air pressure. My experience with Alclad is gravity flow brushes work better at lower PSI, while bottom feed brushes (paint cup) work best at a higher PSI. It's best to experiment.
VR, Russ