Yes, KBS Motor Coater can be applied directly over zinc chromate primer. Zinc chromate is a rust protection primer, and as long as it was applied correctly and is fully cured, Motor Coater will go over the top of it and adhere well to the nice flat finish zinc chromate provides.
Key Facts Zinc chromate is a rust protection primer. Correctly applied and fully cured zinc chromate gives Motor Coater a flat, sound surface to bond to, no additional prep needed. Only step in if the primer is glossy or dirty. |
When Does Zinc Chromate Need Prep Before Motor Coater?
Most properly applied zinc chromate primer needs nothing more than a coat of Motor Coater on top. But if the zinc chromate finish came out glossy for any reason, or if it has picked up dirt, oil, or handling residue, prep it first:
| Step | What to Do |
|---|---|
| 1. Scuff | Lightly scuff the glossy zinc chromate with 320 grit sandpaper to knock down the sheen and give Motor Coater something to grip. |
| 2. Clean | Wash the surface with KBS Klean to remove sanding dust, oils, and grime. Rinse and let dry completely. |
| 3. Coat | Apply Motor Coater by brush, roll, or spray once the surface is dry. |
Pro Tip If the zinc chromate is already flat and clean, straight from correct application, skip the scuff and clean steps entirely. That flat finish is exactly what Motor Coater bonds well to. |
Why Zinc Chromate Works as a Base for Motor Coater
Zinc chromate primer is applied to protect bare metal from rust. Once it's correctly applied and fully cured, it dries down to a flat finish that gives a topcoat something consistent to bond into. Motor Coater is a high-heat engine enamel rated to 500°F that bonds direct-to-metal on both ferrous and non-ferrous surfaces, and that same adhesion carries over onto a sound, flat, properly cured zinc chromate base.
Frequently Asked Questions
Can Motor Coater be applied over zinc chromate primer?
Yes. Zinc chromate is a rust protection primer, and as long as it was applied correctly and is fully cured, Motor Coater will go over the top of it and adhere well to the flat finish zinc chromate provides.
Do I need to prep zinc chromate before painting over it with Motor Coater?
Only if the zinc chromate finish is glossy or dirty. In that case, lightly scuff it with 320 grit sandpaper, clean it with KBS Klean, let it dry completely, and then apply Motor Coater.
Why does a glossy zinc chromate surface need to be scuffed first?
A glossy surface is too smooth for a new coating to mechanically key into. Scuffing with 320 grit breaks the gloss and gives Motor Coater a profile to bite into for a strong bond.
What happens if I paint Motor Coater over zinc chromate that isn't fully cured?
Motor Coater needs a fully cured base to bond to. Coating over zinc chromate primer that hasn't finished curing risks poor adhesion between the layers, so let the zinc chromate cure completely before topcoating.
Ready to Coat Over Zinc Chromate?
Motor Coater ships same day in 40+ OEM-matched colors, rated to 500°F.