As per title, I've 3d printed a pattern out of PLA, my normal process is to sand, fill prep and 2k clear the pattern which I've had no issues with.
2k clearing the pattern is not easy access anymore for the time being.  I have access to plenty of gel coats etc
My question is can I sand, fill and prep the 3d printed pattern, then can I straight up paint a layer of polyester gelcoat (with a wax additive to cure hard) on to the pattern then sand/polish to a high gloss. In turn can I take a mould from said pattern using the Easy composites mould system.

One last question can using the same method be used but straight onto a 3d printed mould. And then laminate a part using wet lay epoxy or resin infusion epoxy?

Many thanks
Josh

Gel coat can't really be applied in a smooth and even way without a spray gun. So this might include an awful lot of sanding. And gelcoat has to be applied quite thick, wich will compromise the dimensional accuracy of your part. Finally, most polyester have poor adhesive propertys to almost anything except polyester itself.
Regarding epoxy there is a problem, that epoxy sticks very well onto polyester moulds, even with several coats of release agent.

An alternative might be an epoxy wich is specifically made for coating applications. This might still be a difficult task to get a perfect surface, but it would solve most of the problems if done right.