Frames are made of food grade polystyrene (PS).
A material of frames does NOT endure a steam smelting. The maximum heat resistance is 65 ºC (149 ºF). At the same time, the polystyrene frames stay straight well in use. Experience has shown that polystyrene doesn’t absorb hydrocarbon from wax, and that is why it doesn’t bend over the years.
The frames need a beewax treatment before use. They can be waxed by diving them in smelted wax or painting them with a little roller with utmost care. Applying too much pressure with a roller, you can cause the frames to bend. Due to hard pressure and high temperature the plastic bends, “remembers” this position and stays there. Even if you apply the same pressure from the other side, the plastic is already deformed.
We recommend the temperature of the wax to be at 60 ºC (140 ºF) when waxing the frames (right at the point when the wax melts). A need of wax is, approximately, 50 g per one frame.
The plastic frames used only in honey supers will stay reusable many years. An advantage of them is durability in extracting process. That’s why many producers of heather honey prefer them.