Surfaces made of colonial wood, like teak, are the hardest to paint. The natural oils in this wood will most likely bleed through. When the wood looks dry or weathered, the oils will probably have dried out, and you won’t have issues when painting. When the wood looks very saturated, there are still a lot of natural oils present. These oils will migrate to the surface and bleed through. Sometimes the wood has been treated with protective oils, meaning even more oil! You can only prevent from bleeding-through by applying a layer of shellac. When shellac was applied, you will have to add bonding agent to your milk paint mix.