You may have dealt with this before…
A knothole in a piece of wood that you are trying to paint that no matter what you do to stop it from bleeding through your finish coat, just seems to magically keep reappearing.
Why is this???
In a nutshell, the knothole bleeding through is a result of the sap from the wood continuing to bleed out through the knothole.
As the sap continues to push, the natural resins of the wood begin to stain the topcoat.
What occurs from here is typically what could be a tiny bit of insanity as people often try every trick on the planet to contain the bleeding knothole.
Pine is a wood that is notorious for being associated with this (often thought of as) unsightly phenomenon.
Most times, what we have found does the best job of neutralizing the knothole from bleeding is a nice dollop of shellac.
Zinsser makes a REALLY fine product for this, it is their ‘BIN’ product.
This alcohol-based shellac sure does seem to work wonders!
For more stubborn knotholes, I would suggest two coats of BIN
If the knothole is really, really stubborn, my suggestion would be two coats of BIN, followed by one coat of a great oil primer
(available from most major paint suppliers).
Few things are more discouraging than having bleeding knotholes pop up on freshly painted surfaces a short time after they are finish coated.
When I first came across this type of failure years ago, I experimented with a number of different products to solve the dilemma.
Through this experimentation, I have found the above mentioned procedure to be the absolute best way of nullifying the bleed through.
If you have a knothole that is simply driving you batty, even after utilizing the above prescribed methodology, feel free to reach out to us, we would be happy to set up a conversation to see if we can help!