Some folks have been ringing lately about a seasonal problem which is coming back into, well… season.
Applying the solvent-based subdued glosses (i.e. semi-gloss, satin, matt) is an acquired skill which can still catch out even experienced players.
The most common problem is finding glossy patches on an otherwise good finish. The reason for this is simple. All the subdued glosses contain a matting agent, like a powder. As the solvents are rising to cure the finish, so are the matting agents. If any catalyst occurs to speed up the curing, the matting will not rise sufficiently and you’ll end up with a plain old gloss. Catalysts can be things like direct sunlight or a slight draft near a window or doorway.
With this in mind, no preparation is too thorough. Mask off doorways or sticky window jams. Pull down outdoor blinds to prevent direct sunlight. Don’t park your Piper Comanche near the front door with both propellers running full bore. That kind of thing.
Also, these subdued glosses need to “keep moving”. The roller should be moving well constantly to avoid lap marks. Lap marks are more of a concern with subdued glosses because the matting agent can make them more prominent.