- Making a picture frame begins with choosing the type of mold to be used. Picture molding is made from wood, aluminum, plaster or plastic. Picture molding, just like architectural molding and counter top edges, is designed by the profile. View a mold from its end or cut a mold in half top to bottom and turn the end toward you---this is the profile of a mold. Picture framing molds are referred to by the name or number of their profile. Mold can be purchased from frame shops and picture mold distributors. Molds, like any decorative item, can be visually classified by style and era.
- Picture molds are measured by height and depth and are sold in varying lengths. Molding specifically designed for picture framing has a lip along the inside edge that the artwork and glass (if used) sits behind and against. Frames are created by measuring the work to be framed, choosing the mold profile and cutting the length of mold needed for each side of the frame by using a miter cut (a 45 degree angled cut). Picture molding is sold in standard sizes and frame shops stock their mold profiles according to these standard sizes. Any time an item requires the framer to cut a standard mold length to fit the work being framed, the frame order is noted as a "custom frame" and the customer is charged more due to the extra labor and expertise involved.
- Once the picture molding is cut, the pieces are assembled in their final shape and attached to each other at 90 degree angles thus forming a square or rectangular frame. Attachment methods are dependent upon the type of material the frame is made of. Metal frames have extruded channels in which to fit an L-bracket that screws adjoining frame sections together. The pieces of a wood frame are usually attached through a process called underpinning which involves using V-nails and a clamping mechanism to ensure a tight and even assembly. Plastic picture frame molding is assembled using glue designed specifically for adhering plastic frames. The pieces of molding are glued at each mitered angle and then clamped together using a band clamp and allowed to cure. Frames ready for placement of glass and art should lay flat when placed on the work surface and offer a stable environment for the item inside it.
