Putty [better] | Repair Window

Here’s a concise, practical guide for repairing window putty (also called glazing compound).

When to Repair vs. Replace

Repair – Small cracks, minor shrinkage, or a few loose spots. Replace – Large missing chunks, widespread crumbling, or rot underneath.

Tools & Materials

Heat gun or hair dryer (for old, hard putty) Putty knife / glazing knife (1½″–2″) Painter’s tool or stiff scraper Glazing compound (oil-based for traditional; latex for modern) Linseed oil (to soften old putty if needed) Primer (exterior wood primer) Caulk gun (if using tube compound) Mineral spirits (cleanup)

Step-by-Step Repair 1. Remove Loose Putty

Scrape out any cracked, loose, or missing putty with a putty knife. If it’s rock hard, warm gently with a heat gun (keep moving to avoid glass damage). Leave sound, well-adhered putty in place. repair window putty

2. Clean the Area

Remove dust, old paint flakes, and debris. Clean the glass edge and wood rabbet (the groove where putty sits). Let dry completely.

3. Prime Bare Wood

Apply exterior wood primer to any exposed wood. Do not prime the glass – putty needs bare glass to bond. Let primer dry per instructions.

4. Apply New Putty