Hollow-core closet doors were varnished. I wanted to paint with semi-gloss white. I sanded doors first. First coat of white didn't really cover, so I put on second coat a couple of hours later. As it dried, I noticed several yellow streaks which appeared to be bleeding through. I then applied a third coat, and streaks are coming through again. I've waited 24 hours, and am wondering if a fourth coat will help (perhaps I didn't wait long enough between other coats?). I would hate to have to start all over with a primer. Can anyone help? Thanks!
Been there. It isn't pretty, and it doesn't go away. Use a shellac based primer to seal the entire door and then recoat with the semigloss. Shellac is totally compatible with oil or latex finishes and seals one from the other. Follow the directions on the can. I usually use a foam brush for this, but it will cause the brush to break up if you take too long. It requires solvents to clean up, so I like to just be able to pitch the brush. Sorry to tell you you need at least two more coats, but you do. These primers are really good for basecoating any previously finished surface because they block stains, have good hiding power, and are easy to apply and to recoat over. Saves on finish paint amounts and effort. Good luck.