Should i use primer or just paint?
You should use primer. Here are some thoughts, in no particular order.
Your “primer” can certainly be a first coat of the final color. A primary use of primer is to show any flaws in seams, gaps etc. during the final prep with any sanding or putty work. That works more effectively with a light color than a dark color.
I have more success getting an even coat of the final color over a base that’s close but not quite the same color. That makes it much easier to check the coverage.
A white or light gray base gives more “pop” to other color finishes. In particular white, yellow or another light shade. Yellow is pretty tricky to get right over a dark base.
Most paints will bond to bare plastic without problems. There are some acrylics that have bonding problems, although most do not. I’ve always struggled with Tamiya Flat Black, so having a primer that reliably bonds to plastic is helpful.
I hope that’s helpful.
It does thank you!
What he said for sure [dto:]
Also if you add PE or resin parts,I find it ties them all together.