Please can you help. I had my door stripped back to the wood I primed them before painting and yellow streaks keep coming through. I then used Polycel stain block painted this on and two weeks later the yellow streaks have appeared again, what can I do to cover these streaks. It would of been cheaper to replace the doors.
It sounds like tannic acid bleeding through to the finish coat. The primer that you used may have been for smoke damage or water stains. Check the label. Make sure the primer is designated to prevent tannic acid bleed through. There are several manufacturers that make this type of primer. If all else fails try a Shellac Primer . We use Bullseye from Zinnser.