I just tried spray painting (compressor and spray gun) for the first time.
I water down the paint to 4 parts paint, 1 part water. The resulting paint
job is a little chalky or sandy. And the satin sheen is no where to be
seen. Meanwhile, my hand paint (with Purdy brush) job, while has a little
brush mark, but it retains the satin finish and looks and feels smoother to
me.

How can I maintain the satin sheen with spray gun? Is it because I didn't
water it down properly?

thx in advance.