Professional Resources — primers

Blackbutt and Tallowwood are two of the most commonly sanded hardwood species in NSW — and two of the most likely to cause problems if you prime them wrong. Tannin bleed is the culprit: a dark, streaky discolouration that appears through light-coloured waterborne finishes when soluble tannins in the timber migrate upward through the coating system. If you've ever applied a waterborne finish to Blackbutt and had the result come up patchy, dark at the edges, or with a greenish-grey tint — that's tannin. And once it's happened, your options are limited. Prevention is everything. Why High-Tannin Timbers Need a...