Bigger Mirrors Demand a Glazier's Skill 1. Glaziers transport large, fragile, custom-cut mirrors upright in racks on specially outfitted trucks. Once on site, they bring the mirrors indoors so they can reach room temperature before installation; this helps moisture evaporate and reduces the chance of cracking during installation. 2. Rubber gloves help maintain a firm grip on the glass, protect hands and keep body oils and perspiration from corroding the protective backing of the mirrors. Large suction-cup "handles" that create a vacuum grip allow glaziers to handle mirrors easily. 3. All sizable mirrors must be mounted with some type of mastic; these adhesives differ according to the mounting surface and drying time. Larger installations typically require two mastics - one that dries quickly to secure the mirrors immediately and a second that dries more slowly to keep them in place over time. Mirror manufacturers recommend mechanical fasteners in addition to mastic. Black bedding compound allows installers to even out the wall and hang the mirrors level and plumb. 4. The quality of the job relies on the skill of the glaziers and their accuracy in duplicating the careful job-site measurements they have taken on the glass when creating cutouts for light switches, outlets and moldings. These cuts are made on large water-cooled saws. The edges are then polished on other specialized equipment.