Choose latex if you need to glaze and paint your window quickly, and oil-based if you’re concerned about a perfectly clean glaze line.
Consider placing a second cloth on the other side of the window to catch debris as well.
For an upper sash, remove the parting beads (the small vertical rails in the frame between sashes) first.
If you’re using a heat gun, wear gloves to protect your hands and keep the gun moving constantly to avoid overheating or cracking the glass. Place a thin sheet of metal (or even some folded-over aluminum foil) over the glass to distribute the heat of a heat gun evenly so the glass doesn’t crack.
If you’re going to install new glass, simply break the glass and remove the shards. Gently tap the glass with a hammer, trying to keep the shards as big as possible. Use a knife to remove any remaining putty or glass from the frame. [8] X Research source Old window panes are very delicate, especially if it’s a single pane window. Be extra careful during removal not to crack or break the glass.
Sand the epoxy first with 80-grit sandpaper. If needed, go over it again with finer sandpaper (like 100-grit or 220-grit). If desired, the repaired crack can be painted over with an acrylic primer and an acrylic paint.
Bring a shard of the original glass with you so the glass cutter can match the thickness. Double pane glass will be more expensive to cut and replace than single pane glass.
Be extra careful with thinner, single pane glass.
If the window sides are less than 12 inches (30 cm) long, placing 1 glazing point at the center of each side is sufficient. If you don’t have a point driver, use a putty knife to gently knock the point into place.
Leave no gaps or hollow spots in the putty. Make sure it’s evenly distributed all the way around the window’s edges. Alternatively, oil-based putty can be heated by setting the can in a bowl of hot water for a few minutes.
For a professional look, try to smooth out the putty in one single pass per side. Oil-based putty will take weeks to fully dry and harden. Avoid touching it after the smoothing process.
Take extra care during this process not to touch or disturb the smoothed out putty.
If you notice any stains on the glazing, wait for it to dry and remove the dirt later rather than trying to clean it while the putty is still wet.
Clean the glass before painting so that there are no remaining putty oils that can get under the paint. Use a small brush to paint over the glazing to ensure accuracy and a clean finish.
