The black paint coating (KTL) has the following function:
- protects the steel from rust during storage
- protects the steel against rust outdoors after installation
- enhances the parts optically and haptically
- extends the life span
From a static point of view, small defects do not play a role: All parts are dimensioned so that rust does not matter. The big advantage of the tree screws: As the tree continues to bind the screws, the connection becomes stronger from year to year (see thickness growth and reaction wood). Optical defects can be easily corrected with black paint: paint spray, car paint stick, permanent marker, etc.