Most thermoset powders keep 6 to 12 months below about 80 F with low humidity; low-cure and fast-cure grades keep less. Heat starts the cure reaction early and fuses particles into lumps, a fault called caking or sintering, while moisture makes powder fluidize badly and charge poorly. Old powder often loses flow and shows more orange peel even when it looks fine in the box.
This box sat in the hot trailer all summer, it's caked solid, way past its shelf life.
Also heard as
- storage life
Related terms
Low-cure powder
Powder formulated to cure at lower oven temperatures, used to save energy or coat heat-sensitive parts.
Flow
How far and how smoothly melted powder spreads out before it gels, which sets surface smoothness.
Feed hopper
The fluidized container that holds powder and supplies it to the gun pumps.
Orange peel
A dimpled surface texture like the skin of an orange, the most common appearance complaint on powder.