Yes, RustSeal can be top coated, and on anything that sits in direct sunlight it should be. RustSeal's rust protection does not degrade under UV, but its color and sheen will chalk and fade, so an opaque, UV-stable topcoat is what keeps it looking right. There are three proven ways to get the two coatings to bond.
A clear coat will not protect RustSeal from UV. DiamondFinish Clear and KBS MAXX Clear let ultraviolet light pass straight through to the RustSeal underneath, which still chalks and fades. For sun-exposed work use an opaque topcoat such as BlackTop, KBS Top Coater, or KBS MAXX.
The Three Methods
Pick whichever one fits your schedule. All three produce a properly bonded, fused coating system.
- Wet on dry. Apply the topcoat once the final coat of RustSeal is dry to the touch and does not leave a fingerprint, usually 3 to 6 hours depending on temperature and humidity.
- Cure and scuff. Let the final coat of RustSeal fully cure for at least 24 hours, scuff with 320 grit, then apply the topcoat.
- Cure and prime. Let the final coat fully cure for at least 24 hours, dust with Fusion Self-Etching Primer, let the primer cure about 30 minutes, then apply the topcoat.
Out of direct sunlight, such as the underside of a car or an interior frame rail, RustSeal does not need a topcoat at all. It seals and serves as a good-looking final finish on its own.
Frequently Asked Questions: Top Coating RustSeal
Yes. RustSeal can be top coated with any opaque paint system. There are three effective methods: apply the topcoat while the final coat of RustSeal is dry to the touch, usually 3 to 6 hours; or let it fully cure at least 24 hours and scuff with 320 grit; or let it fully cure at least 24 hours, dust with Fusion Self-Etching Primer, and let the primer cure 30 minutes first.
No. A clear topcoat such as DiamondFinish Clear or KBS MAXX Clear cannot provide the UV protection RustSeal needs, because ultraviolet light passes through the clear layer and reaches the RustSeal underneath. Use an opaque, UV-stable topcoat such as BlackTop, KBS Top Coater, or KBS MAXX instead.
Only where it sees sustained direct sunlight. RustSeal is not intended as a final finish on surfaces consistently exposed to the sun, because repeated UV exposure cosmetically alters its color and sheen. In areas out of direct light, such as the underside of a car, RustSeal seals and serves as a good-looking final finish with no topcoat needed. Its rust protection does not degrade under UV either way.
If you are top coating while the RustSeal is still dry to the touch, that window is usually 3 to 6 hours after the final coat, depending on temperature and humidity. If you miss that window, let the coating fully cure for at least 24 hours and then use the scuff method or the Fusion Self-Etching Primer method instead.
Use 320 grit. Scuffing is only needed if the final coat of RustSeal has fully cured for 24 hours or more. If you are still inside the dry-to-the-touch window, no scuffing is required.
Still deciding which topcoat suits your project? Read the full RustSeal directions or contact us.
