Wednesday, May 18, 2016

When Compo Goes Bad

Frame as delivered

This frame is typical of late Victorian compo (composition) work. This material, composed of whiting, rosin and glue has the consistency of cookie dough when fresh, and can be pressed into molds. When dry, it is steamed, which reactivates the glue and also allows it to be pressed onto curved shapes, such as the half-cylinder outer rails of this frame. Over time, however, compo dries out, and can separate from the wood - particularly if the frame is knocked around.

Missing sections of compo ornament

Repairs like this, which look minor, can be difficult because molding and casting is done on a curved section. The original compo was in relatively large sheets that were attached to lengths of molding. Since you cannot easily mold a single piece to match this, you wind up piecing it in, trying to use as much of the original as possible.

Molds and casts

Piecing in replacements

More falls off while frame is being worked on

A tedious job, but now the frame is once more complete.