Brush Liquid Masking Onto the Glass Before Painting Window Trim

The Problem

Painting window trim means protecting every pane, and taping glass is the slowest masking there is — straight runs, corners, and glazing lines on every light of every sash. It's the reason painted windows stay unpainted for years.

The Technique

1. Brush liquid masking tape over the glass along the trim lines — a coat right on the pane. Precision doesn't matter: getting it on the glass is the job, and where it laps onto the trim it acts as a primer rather than a problem.
2. Let it dry, then paint the trim normally — she did three coats, painting over the masked glass edges without ceremony.
3. Let everything dry overnight.
4. Score along the trim edge with a utility knife, then peel — the film releases from the glass in satisfying sheets, taking the overpaint with it and leaving a crisp line.

The comparison isn't masking versus not masking — it's peeling film versus scraping dried paint off glass pane by pane.