Sticker Stain
A discoloration appearing on lumber at points where drying stickers contact the wood surface during seasoning, typically showing as dark or grayish bands across the board.
In-Depth Explanation
Sticker stain develops when moisture, heat, and chemical reactions between the sticker material and drying lumber cause localized discoloration at each contact point. The stain is most common in light-colored species like maple, ash, and birch, where the contrast is most visible. Chemical sticker stain results from tannin or extractive migration and oxidation, while fungal sticker stain is caused by mold growth in the warm moist micro-environment. Preventing sticker stain involves using dry clean stickers made from the same species, ensuring good air circulation, and beginning the drying process promptly. While primarily cosmetic, it can reduce the grade and value of appearance-grade lumber.
Usage Example
Several maple boards had visible sticker stain every 24 inches where the drying sticks had been placed.