A concave mirror curves inward in the middle forming a hollow. These mirrors are used in automobile headlights to focus the light from the headlight. The light does not get diffused. In addition, these can be used to focus light rays at a point for heating. Generally, these mirrors come with a molded or metallic frame. You can be frame a concave mirror with a wooden frame in round shape; the frame can be provided a wooden handle. You can frame the mirror by cutting circles from sheets of plywood and laminating them to make the round frame to accommodate the curvature of the mirror. The process is simple. Finally the frame can be paint finished.
Step 1 - Measuring the Dimensions
Measure the diameter and height of the mirror. In this article, we will use a mirror measuring the diameter is 5 inches and height is 1/2 inches as an example.
Step 2 - Cutting the Plywood Pieces
Cut a 3/4 inches thick plywood piece in 8 by 8 inches square shape (about 3 inches bigger than diameter of the mirror). Cut 2 more pieces of 1/8 inches thick plywood also 8 by 8 inches square. Nail all the ply wood pieces together at the center.
Step 3 - Cutting the Outer Diameter
Attach the circle jig to the router. The jig has a row of holes for different diameters. Select the hole that matches nearest to the outer diameter 6 1/2 inches and fit this hole on the nail fixed in the center of plywood pieces
Rotate the circle cutting jig anticlockwise around the center pivot point and cut out the outer circle using the router.
Step 4 - Cutting the Inner Circle
Separate all the 3 pieces of ply. The 3/4 inches circle is to be used in the middle of the frame as a ring while one 1/8 inches thick piece will be fixed on back and other 1/8 inches thick ring is to be fixed in front.
Fix a nail in the center of 3/4 inches circle and mount the jig on it to the nail hole for 5 inches or slightly larger diameter that matches it to cut inner housing diameter for mirror. Cut out the inner circle, which is slightly over 5 inches in diameter. It is now a ring.
In the same way, cut a 4 1/2 inches diameter circle in one piece of 1/8 inches thick circle to make another ring.
Step 5 - Assembling the Frame
Join both 3/4 inches and 1/8 inches thick rings together with adhesives so that their outer circumferences are matching. Let it dry. Fix the back ply circular piece with small screws on back.
Step 6 - Fixing the Handle
Drill a hole to match the wood handle on periphery. The hole should be aligned axially and be of correct in diameter and depth. Glue the handle to frame and allow it to dry.
Step 7 - Finishing
Sand the edges at mirror opening and outer side. Paint the frame both inside and outside with a brush and let the paint dry.
Step 8 - Assembling the Mirror
Place the concave mirror in the frame to rest its rim on the front ring. Put some tissue paper behind the mirror. Pack it on the back with foam to avoid shaking. Fix the back with screws. Your mirror is ready for use.