Select a brushed nickle frame style that is rated for the weight of the mirror. Smaller metal frames often assemble with slotted, pressure-held screws that may be insufficient for substantial weights. Mirrors larger than 24-by-36 inches often look best with frames wider than 4 inches.
Assemble the frame using the fasteners provided with the frame by the framing company. Place the assembled frame face down on the table.
Cut cardboard the same size as the mirror. Place the cardboard over the back of the mirror to protect the mirror from gouges and scratches.
Insert the mirror and cardboard face down into the frame. With some frame styles, you will need to assemble the top and sides, leaving the bottom part of the frame detached. With these styles, the mirror will slide into the frame through the bottom opening. Attach the bottom part of the frame following the manufacturer's recommendations.
Position pressure springs between the cardboard back and the back of the frame. Place the springs every six inches along all sides. Typically the spring is 2 inches long and shaped like a soft bell curve. Press down on the center of the spring and slide it into the frame. When you release the pressure of your finger, the spring will press against the back of the cardboard to hold the mirror forward.