Painting questions

[Helper Monkey]

I am new to painting models with an airbrush but not new to airbrushing. Before I painted using a brush or rattle can.

I would like to know if anyone has ever painted in layers. My plan is using my airbrush to prime the car, sand it, paint a few layers of pearl and then then paint it again with a few layers of transparent blue. I was wondering if anyone thinks I should sand the Pearl before I apply the blue? I have noticed a few oddities in my pearl coat, such as what appear to be scratches. I  am assuming that If I do sand I need  to wet sand  or at least use a  super fine grit.

To let everyone know I primed using AK interactive white surface primer. I will be using Golden's new High-flow acrylics. I am going to use the Iridescent Pearl (fine) and then transparent Phthalo Blue (green shade). This  project is also serving as a test bed to see how the  paints hold up and act.

[Longbox55]

What grit are you using to sand the primer? If you're seeing "scratches" in the pearl, it's more likely sanding scratches in the primer coat. You may need to sand out to a finer grit on the primer before you do the pearl. You will want to void sanding the pearl, as it will ruin the pearl effect. If you do sand it, you'll need to give it at least 1 or 2 more coats to bring the effect back.

[Helper Monkey]

I was finishing off with a 800 grit. I recently bought some 1500 for use but did not use it on this model. I was also using some kind of nail buffer that I get cheap from a Japanese dollar store called Diaso. No idea what the grit is cause A I can not read Japanese and B not sure if they even put it one there. http://www.daisojapan.com/p-9852-nail-file-wcushion-3-steps-12pks.aspx They seem really fine something like a 900 a 1600 and a 2000 but this is only a guess. 

However, I am waiting about an hour to sand the coats and now I am noticing that the paint is easily marred. I assume its due to the nature of acrylic paint being softer than enamel or that it has not fully cured yet. If this continues to be a problem I am going to look into adding Golden's GAC-200 which should harden up the paint film a bit. 

I am gonna sand down those areas, and repaint again with a few more coats of pearl. I may post some pics to show how it comes out.