Don Vandervort, Head Homeboy, has written more than 30 DIY home improvement books, been a segment host on HGTV, served as MSN.com's home improvement expert and written countless magazine articles.
Old glazing compound can become brittle and fall out. When this happens, air can leak in around the glass panes or—worse—the glass can fall out. To replace glazing compound:
1) Remove the old glazing compound with an old chisel and hammer (wear safety glasses and be careful not to drive the chisel into the edge of the glass). If necessary, soften the compound with a heat gun, but be careful not to train the heat on the glass or it may break.
2) Use your fingers to apply glazing compound around the perimeter and then smooth it at an angle with a putty knife to match the other panes. Wet the blade if necessary.
3) Allow the compound to cure, about one week, and then paint.
