Author: Duffy Hoffman
Contributors: Bob Yapp, John Leeke
Title of Treatment: Clean Old Glass
Class of Treatment: [ ] Maintain, [ ] Stabilize, [x] Repair, [ ] Upgrade, [ ] Exception
Type of Treatment: [ ] Traditional, [x] Contemporary
Condition to be Treated:
Old glass panes have hard putty and paint along the edges.
Description:
Old glass must be cleaned before use in reglazing. This is a soak and wet-scrape treatment that focuses on the surfaces of the pane near the edges. When using this treatment, further glass cleaning will be needed after glazing and painting.
Typical Procedure:
1. Soak glass vertically in a container big enough to allow complete immersion. Fill the container with water and a small amount of detergent. Allow glass to soak until all the old putty and paint is soft enough to remove.
2. Scrape off the old putty and old paint with a plastic putty knife or plastic automobile windshield scraper to avoid scratching the glass.
3. If necessary, scrape carefully with a single-edge razor blade in a holder. First wet the glass, then scrape. Never scrape dry glass because it can scratch the glass surface.
4. Wipe off the pane with a soft cloth and set the glass aside to dry.
Materials:
Detergent, biodegradable, degreasing (do not use any products with the words "oil soap").
Single-edge razor blades
Soft cloths
Quality of Results
Best Work: Glass pane is clean around edges. There may still be soiling in the middle of the pane. No additional scratches were added from removal of putty and paint. Glass was handled carefully with no breakage.
Adequate Work: Glass pane is clean with slight hazy residue around outside edges. No additional scratches were added from removal of putty and paint. Glass was handled carefully with minimal breakage.
Inadequate Work: Glass is not clean with substantial residue left around outside edges. Additional scratches were added from removal of putty and paint. Glass was not handled carefully causing breakage.