One big part requires different sheens for each section.

How do I separate a different sheen of clear coat for a different portion of the same part?

Here is an example:

I glued the engine block in one piece. The block is not supposed to be in one sheen, but 3 different sheens of clear coat (gloss, matte, semi gloss).

How do I separate each portion of the engine, for a different type of sheen?

I’m guessing that you should mask the parts that don’t have the sheen.

Correct as usual, King Friday.

Bill

Could be a little time consuming but you’re exactly right. Just mask the portions you need kept as-is. Then spray your next sheen. Let that dry for a few hours, mask it, then spray the third sheen. It will look great when it’s finished. Just needs a little extra work.