Picture frame - Box frames
A box frame is a frame that is deep enough to accommodate a frame slip. The frame slip is made from the same material as the frame, is mitred in four pieces and fitted into the frame inbetween the underside of the glazing and the backing / item.
The depth of the frame slip in the frame is included within the frame code and description. For example, the frame Bx1 – 33mm Painted black grain 30mm Deep Box, is a 33mm wide frame with a 30mm deep frame slip inside. If you look at the cross section above, the frame slip is the material in-between the glazing and the backing / item. In this example there is a 30mm space in-between the glazing and backing / item.