Subject: Re:vallejo primer to thin or not to thin. Vallejo's website recommends not to thin it. I shoot it unthinned, at 15-20 psi (I have a pretty bad compressor), and it works fine. I do have way more dry tips than with properly thinned paint, but nothing terrible.

Do you need to thin down Vallejo primer?

You don't need to thin it down, and thinning it can cause some flow and drying issues. I use a . 21mm needle in my airbrush and I can spray the primer through with no problem. It is designed to be thin enough to spray without added thinning.

Do you dilute Vallejo primer?

Vallejo recommends not diluting their primer ( , section 7), and using a 0.35mm needle should do the trick.