Dont use Gardz on doors or trim!!! Its for problem DRYWALL, or to seal cheapo flat paint. NOT for trim or door usage. Use a primer designed for your purpose.
What were you hoping to accomplish with Gardz, anyway? You doent need to 'seal' your black paint. The paint is self sealing. You need something that A; Sticks, B: is sandable, and C: white pigmented. Gardz is none of the above.
Unless the black is oil, I probably wouldnt even use a primer. I'd clean, sand and topcoat till it covers. If you fill any chips with spackle or anything, spot prime.
What were you hoping to accomplish with Gardz, anyway? You doent need to 'seal' your black paint. The paint is self sealing. You need something that A; Sticks, B: is sandable, and C: white pigmented. Gardz is none of the above.
Unless the black is oil, I probably wouldnt even use a primer. I'd clean, sand and topcoat till it covers. If you fill any chips with spackle or anything, spot prime.
