Refinishing Nitro over Poly - questions

[Twigman]

I have a bright yellow precision that I built a few years ago.

It was a finished Warmoth body in Grafitti Yellow Poly.

I don't like the colour.

I am planning to refinish with black nitro over the yellow poly.

I plan to sand the yellow but not all the way off, perhaps with 400grit just to key the surface for the nitro paint.

Will this be enough or should I really strip all the yellow back to wood?

I don't really want to have to then fill and sand so would prefer just to leave the yellow on.

I plan to airbrush the black nitro on.

A couple of questions:

1  How dilute (xparts paint to xparts thinner) would be best?

2  What volume of paint is required to cover a precision body? Diluted or Undiluted?  - I ask this to establish whether my current (modelling) airbrush would have sufficient capacity in its resevoir without having to refill it too frequently.

 

I know these are proper newb questions but we all have to start somewhere.

Edited 2 hours ago by Twigman