In response to many customer inquiries requesting a quick drying and easy-to-apply coating which enables a restorer to quickly topcoat POR-15 and other basecoats, POR15 has developed this Self-Etching Primer . With this product, you can even topcoat POR15 that has been in place for months or years. POR15 Self-Etching Primer is NOT a high-build primer, like POR15 Tie Coat Primer , but it can be sprayed on almost any painted surface and can be topcoated in 15 - 30 minutes.  This fantastic high-tech coating will gently etch tough and glossy, making the perfect surface for bonding to POR-15 Rust Preventive Paint , and all topcoats. It can be sanded lightly, and, if desired, multiple coats may be applied. Only available in an Aerosol Note: that very old, cured POR-15 finishes may still require light attention with some coarse sandpaper.