I painted a new pine bookcase and forgot to prime/seal it first!

You can use shellac.

You can rough the last coat and put a primer on it to prevent the knots from bleeding. I would go with Kilz Original or Bullseye 1-2-3. Those are the only ones that block it in my experience. Then paint over that. It will just mean that you quite a bit of paint on it.

You will need to shellac the knots - even if you primed first these will bleed through without shellac. Do that, prime and then paint. It will still be great. :)

Hello. They do make me aerosol primers and shellacs—- that might be an option to consider.

Knots are very tricky. Our contractor in advertently stained our porch ceiling and nearly every year we are shellacking priming and re painting white over the knotty constellations. They can be particularly annoying and persistent. Good luck.

Yes, use shellac to stop the bleed through from the knots. After the shellac has dried, then prime and paint.

I would use an oil based primer (such as Rustoleum and probably two coats) and then reapply your paint.

Another coat should be good but don't put on a heavy coat because you didn't prime. Thin coats that dry completely work much much better. You can always do a 3rd coat if need.

You can now prime and seal, then paint two more cats and seal it. No need to sand down to bare wood, but it would make the project look more well-done, if yoou sanded before priming.

Prime it with Kilz primer and two coats of paint should do it. You don't need to use shellac

Hi! It isn't too late! Apply the sealer now and then repaint. The sealer will be more effective if you lightly sand the dried paint first and then wipe it clean. I've had this happen and it will be fine!

just use a primer over what you have painted let it dry then add your paint color

Put a thick primer on it then keep going

After that many coats it should have covered. Perhaps try some acrylic latex or enamel if you can find it....

A good stain blocking primer such as Kilz or Zinser 123 should do the trick. Then you can repaint over the primer.

Give it a good sand, tack clothe it, then prime with Zinseer Bin to seal the wood oils and knots (I like to do 2 coats on knots), light sand, then use your semi-gloss.

Seems odd that after four coats of paint, you can still see the wood. Or are you referring to still seeing raised grain? If that’s the case, it won’t go away. But, you can put on a coat or two of primer and keep going.

Use "Stain bloc" all over, May need 2 coats. Good luck!