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Choosing and Buying Glass

You probably don’t live in an all-glass house or throw stones. You should, however, know how to buy and install glass for that broken window or storm door that eventually seems to be an affliction for us all. Standard glass, available at most home centers and hardware stores, is the most common. Unless the pane is very small, spend a little more for double-strength glass; single-strength glass is likely to crack if bumped lightly. A glass shop carries more types of glass. For a very large older window, or for shelving or a tabletop, purchase plate glass, which is very thick. Tempered glass is recommended for doors because it has extra strength.

Safety glass, commonly used for automobiles, breaks into rounded pieces rather than sharp shards. Wire-reinforced glass provides security where you might expect a break-in. Acrylic is often chosen over glass in situations where the pane is likely to be bumped. Acrylic has some disadvantages, however. It scratches easily and may look dingy in time. In addition it is flexible, making it easy for a burglar to break. A variety of tinted, frosted, or patterned glass styles allow light in while obscuring the view; they are sometimes referred to as “obscure glass.”

Glass block is several inches thick and comes in several styles. The blocks are mortared together like a brick wall. The result is a decorative wall that admits filtered light, yet is nearly as strong as a masonry wall. You can order a grouping of blocks preassembled to fit your opening, or you can assemble them yourself using special mortar, spacers, perimeter gaskets, and wire reinforcement. If a double- or triple-glazed pane is broken, take the sash to a glass shop and have them make up and install the pane. Be sure that the new pane has the same special features of the old one - low-E glazing, for instance.

If a standard pane has broken, first remove all the broken pieces and clean out the opening. Measure the opening carefully, then subtract 1/8 inch from the measurement in each direction. The resulting extra space allows the glass to “float” in the sash and helps prevent it from breaking. Either have a glass dealer cut it for you or buy a large piece and cut it yourself.

Selecting Glass

Type

Strength

Installation

Cost

Uses

Standard SS

Poor

Easy

Low

Windows, doors, storm doors and windows, cabinet fronts, pictures

Standard DS

Fair

Easy

Low

Same as SS

Plate

Good

Easy

Medium Tabletops, shelves, high-quality mirrors

Tempered

Excellent

Easy

Medium

Windows, doors, patio doors, skylights, shower doors, and fireplace doors

Safety

Excellent

Difficult

Medium

Storm doors, patio doors, skylights, and tabletops

Wire

Excellent

Difficult

High

Doors, commercial jobs, basement windows, and crime-prevention placement

Insulating

Good

Difficult

High

Windows, patio doors, and large glass areas

Tinted

Good

Moderate

High

Windows, doors, large glass areas, commercial windows, and skylights

Frosted

Good

Moderate

High

Bathroom windows, shower doors, and tub enclosures

Patterned

Fair

Easy

High

Entrance windows, decorative accents, cabinet fronts

Mirror tiles

Poor

Easy

Medium

Accent walls, bathrooms, bedrooms, cabinet liners

Glass block

Excellent

Difficult

High

Translucent windows and interior walls

Cutting Class

A smooth, even score with a glass cutter lets you snap the glass with ease. The trick is to make the right score in a single stroke. If you exert too little pressure on the glass, the cutting wheel will skip; if you exert too much pressure, the edges will crack or chip. Always work on a flat, clean surface. Guide the cutter with a strip of hardwood that’s been dampened so it won’t slide across the surface, or use a carpenter’s square. Don’t wait too long after scoring to snap glass—it tends to heal itself. Do not attempt to cut safety glass.

Tools: Glass cutter, square, tape measure, wooden straightedge, and light all-purpose oil.

1. Score a line. Measure and mark each end of the cut with a short score mark. Place the straightedge about 1/8 inch past the marks—the glass cutter does not actually cut right next to the straightedge. Lightly lubricate the line, then draw the cutter along the straightedge in one firm, smooth stroke.

2. Break the glass. NOTES Wear work gloves and safety glasses. Lay the glass with the scored side up over a board, with the score line directly above the corner of the board. Press down on both sides until the glass snaps. If you need to cut off a sliver that is less than an inch wide, use the glass cutter’s teeth.

3. Nip the glass edge. Nip away irregularities with pliers. Teeth in the glass cutter also are designed for this purpose. Smooth rough edges by rubbing gently with a sanding block. For a very smooth edge (say, for glass that will be used on a tabletop), rub with an oilstone dipped in water.

Secure a mirror with clips. Secure large mirrors with special steel clips or strips sold at glass outlets and home centers. You can cover the clips with molding. To cover a wall with mirror tiles, square them up as you would ceramic tiles . Secure with double-sided tape or mastic.

Safely store extra glass. Secure extra windowpanes by sandwiching each between two pieces of plywood and taping the package together. Store the glass upright rather than laid flat. Mark the package so when you go to the storage area it’s not handled roughly.

Replacing Windowpanes

Faced with a broken window, you have three options: Remove the sash and take it to a hardware store or glass shop for reglazing; buy a new pane that is cut to size, and install it yourself; or cut the glass yourself from standard-sized sheets kept on hand for such emergencies. Dismantling a window is sometimes far more work than simply replacing the glass. Cutting glass isn’t difficult, but you might break a pane or two before getting the knack. A hardware store will cut glass to the size you need.

Tools: Putty knife, scraper, caulking gun, and paintbrush.

1. Chop off the old glazing. NOTES Wear heavy gloves and long clothing when handling broken glass. Carefully pull out all the pieces of the old pane. Chipping off old glazing compound can be the hardest part of the job. Use a putty knife or old chisel, or soften old glazing with a soldering iron or heat gun.

2. Roughen the groove. Scrape away the last of the old compound, then roughen the groove with a scraper so the new glazing compound will adhere properly. Be sure to remove all the old glazier’s points, which may be tiny metal triangles instead of the push-type points shown in Step 6.

3. Measure the sash. Sashes aren’t always perfectly square, so measure at several points, then subtract 1/8 inch from each dimension to determine the glass size. Have the glass cut at a hardware store or glass shop, or cut it yourself.

4. Prime the groove and apply a bead of glazing. Prime the groove with linseed oil, turpentine, or oil-based paint. Untreated wood will draw oil from the glazing compound, shortening its life. Before you insert the new pane, apply a 1/8 inch-thick bead of caulk or glazing compound. This helps seal and cushion the glass.

5. Press the pane into place. Line up one edge of the pane in the sash, lower it into place, and press gently with your palm or fingertips to seal it into the glazing compound.

6. Add glazier's points. Approximately every 12 inches around the perimeter, press a glazier’s point into the sash with a putty knife. Don’t push too hard - you may crack the glass.

7. Apply glazing compound. If the glazing compound is in a can, grab a hunk and roll it into a “snake.” Alternatively, use glazing compound in a caulk tube. Apply a generous bead of glazing compound. Press it into place to make sure it sticks to both the glass and wood.

8. Bevel the compound. Working in only one direction, firmly draw a putty knife all along the bead. If the compound sticks to the knife, wet the knife with turpentine. If small ridges appear, lightly run your finger in the opposite direction to smooth the compound.

9. Paint the compound. Let the compound dry for a week before painting. Paint should overlap the glass about he inch for a tight seal.

Clips for a metal sash. Spring clips substitute for glazier’s points in steel sashes. Install as shown here. Metal windows needn’t be primed before installing the glass.

Gasket for storm window. In an aluminum storm window, a rubber gasket, forced into place with a putty knife, holds the glass. If the gasket is cracked or broken, replace it.

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