Although not necessarily in context, but whenever we have to prepare shitty composite mouldings for spraying we use the following sequence of operations..... (legal note - Mark, I am in no way implying the docks have a shitty finish so don't send the boys round).........

- Wipe on a "rag filler" - a creamy filler which is literally wiped on, allowed to dry and then sanded off (to address the surface porisity)
- Apply body filler to any blemishes & sand flat
- Spray with a filler/primer & sand flat
- Paint finish of your choice

As with all things of this ilk, you reap what you sow. NO EFFORT = SH*T JOB

Cheers, Sim