I'm sure that people have seen this where you would be painting something white or lightish colour only to have the resin from the knots bleed through paint sometime later. Similar to what you see in the following picture.
For my latest project I knew this was a possibility so I coated the knots with some shellac. However after about a month it still came through. I am sure if it was dried properly this might not have happened but the project was a large storage shelf that did not fit in my oven.
So I have 2 related questions:
- What should I have done to try and prevent this?
- What can I do to correct the damage after it has occurred.