Plastic sheets expand and contract due to its relatively high coefficient of thermal expansion. Polyxpand is designed with a wing feature to cut an enlarged expansion hole in the skylight material to allow for skylight sheet movement under weathering effects. This expansion hole will prevent plastic sheets from damage as a result of stress and fatigue due to thermal expansion and contraction. The Polyxpand wing feature is also designed to break oﬀ automatically when it comes into contact with the steel substrate.
The Thunder-Shot point on Polyxpand provide precise positioning and is designed to penetrate batten thickness ranging from 0.75mm~5.5mm. For optimum performance, BDN Fasteners recommends drilling the Polyxpand screws @1800~2000rpm.