Ask the Expert Question-and-Answer Archive

by Ron Joseph

December, 2004

Clear Lacquer Over Epoxy

Q. Can clear lacquer be sprayed over epoxy?

I principle I would say "yes", but you need to bear several things in mind:

What is the resin of the clear lacquer? Some resins might not have as good adhesion to epoxy as others.

Will the coated part be exposed to the elements and especially to sunlight? Epoxy coatings tend to chalk after they have been exposed to sunlight and this can affect intercoat adhesion.

Will the coated part be exposed to chemicals and/or solvents? Nitrocellulose lacquers do not perform well when exposed to solvents and some chemicals.

If it is exposed to sunlight will the clear lacquer incorporate a UV blocker? This might prevent the epoxy from chalking.

How long after you apply the epoxy will the lacquer be applied? Epoxy coatings become inert after they have fully cured and you might not get good adhesion between the lacquer and the epoxy.

If you intend to apply the clearcoat over the epoxy I strongly suggest that you conduct some laboratory exposure tests to confirm intercoat adhesion after the coating system has been exposed to the environmental in which it is intended.

Good luck.

Ron Joseph