Which self-drilling fasteners should I use to fix a composite panel?
- Read time: 2 minutes
- Date: 04 May 2021
- Rainscreen & Façades
High thread: a larger diameter thread under the head of the fastener also known as a high thread, which ensures the bonded washer is clamped tightly to the top sheet of the panel, creating a weatherproof seal
Free-spin / washer compression zone: to prevent thread stripping in thin materials, while creating a superior seal
Why are high threads important?
Composite panels are made from a thin bottom sheet of metal, a layer of insulation material and a thin top sheet. If there is any loading (weight) on the panel, it can cause the insulation to compress. This causes the top sheet to move away slightly from the bonded washer – a gap of less than 0.5mm can cause a leak. The high thread engages the top sheet of the composite panel ensuring an effective seal even under loading.
What else is important when selecting a self-drilling fastener for composite panels?
As with any application, when choosing a self-drilling fastener, you must consider the build-up depth, substrate depth and the type of materials being fastened. Here are some important points to consider:
Fastener length
Type of drillpoint
Fastener material
Head style and shape
