Secure Underside Masking

What happens here

After masking the initially exposed surface, carefully manipulate or 'flip over' the flexible weather strip to expose its underside. With the underside now visible, apply additional masking material to this newly exposed surface. This step is crucial for ensuring the entire weather strip is completely protected from paint, even if it moves or shifts during the painting process.

Goal: Completely mask the weather strip, including its hidden underside.