How I use filler primer, gray primer, and black primer to inspect and prepare 3D printed helmets, plus the spray-can grip that makes long coating sessions easier to control.
Quick answer:
Use filler primer when shallow print texture still needs refinement, gray primer when you want a neutral inspection surface, and black primer under metallic, dark, or battle-worn finishes.
The important part:
Primer reveals problems; it does not replace proper sanding or repair deep seams. Match the primer to the finish going over it, and check product compatibility before layering different coatings.
Safety:
Follow the product label for ventilation, protective equipment, temperature, drying time, and disposal. If the spraying environment is not suitable, wait for better conditions.
These recommendations come from my own workshop process. I explain where each item fits, including the tradeoffs, so you can decide whether it suits your build.
Best for: Building and refining shallow print texture and sanding marks before colour
This is the filler primer I use after the major seam work is complete. It gives me a consistent inspection coat that can be sanded back where needed.
Shop This Product on AmazonBest for: More comfortable, controlled trigger-style spraying during longer coating sessions
I use the grip on compatible cans to reduce finger fatigue and keep my passes steady. It supports good technique but does not replace it.
Shop This Product on AmazonBest for: A dark foundation under metallic, dark, and battle-worn finishes
I use black primer when the finish benefits from a darker foundation. It unifies the surface and gives later metallic tones and weathering more depth.
Shop This Product on AmazonBest for: A neutral inspection surface before lighter colour coats
I use gray primer when I want an easy-to-read surface for spotting scratches, low areas, and other defects before moving into colour.
Shop This Product on AmazonWant to see more of the build process? Visit the workshop page for behind-the-scenes progress, or browse the finished prop catalog to see what is available now and what can be made to order.