Priming procedures

can i paint(paintbrush) the liquid surface primer just over a particular area where there are scratches or sink holes?

Sure... But you'd be better off filling the sinkholes first...

Will unsmooth finish of the primer affect my final coat of color?

Not enough to matter, IMHO... Unless you have like, grey primer on the base material that's very dark, and are painting with a color that is very light... Then you're going want a uniform undecoat..

Hi there,

can i paint(paintbrush) the liquid surface primer just over a particular area where there are scratches or sink holes? Or do I have to paint it over the entire surface evenly and fully coated? Will unsmooth finish of the primer affect my final coat of color? Thanks for all replies.

THREETRAN

"And we did our computing in priMORDial darkness—

    back when I was a boy!"  

Oh, sorry, I forgot to mention that I'm paintbrushing it. Thanks for your reply.

Btw, what software did you use for your program?

1. Dilute priming paint to spraying viscosity.
2. Put paint in airbrush. Adjust air pressure and distance to model.
3. Point airbrush at model.
4. Press valve on airbrush.
5. Wait for primer to dry.
6. Wait for primer to cure.
7. Look for surface imperfections revealed by primer.
8. If found, fix surface imperfections. Else, go to step 10.
   
9. Go to step 1.
10. Apply finish coat or coats.

Okay, enough sillyness. There are three reasons to apply a primer:

1. To find surface imperfections. The flat finish and slight contrast in color of the primer makes this much easier.
2. To back up a finish color, such as white, yellow, orange and some reds that need it.
3. To improve adhesion of the final coat. This is rarely needed in scale modeling if you get the plastic clean. That being said, some resin parts benefit from priming even when clean.