Saturday, April 16, 2011

The Leg Repair

Usually when a leg breaks on any piece of furniture its an easy task to put the parts back together. In the case of this leg however, there is little if any support for such a cross grain break. 

The rule of thumb I was taught was that the gluing surface should be a minimum of 6 to 1. Six times longer than the thickness.

Obviously not possible here so it has to be doweled through the break.The next problem is - how can you possible get a dowel aligned straight through the break when the surface is so irregular?

If the break was closer to either end of the leg you could glue it together and then drill through the break after it had dried.  In this instance the break is 16 inches from the closet end so not a possibility.

So... I squared the leg up on my mitre box and cut through the leg just above the break. Glued the break together, centered the two sides and drilled the dowel hole. I glued the joint using West System epoxy, a material best known for boat building. It provides an incredible amount of strength and ages well.

With the addition of a small amount of micro balloon filler it also fills gaps and voids in the joint. Slight pressure from a packing band to hold it together until it dried and we're on to the finishing process.

              

Glues and Adhesives

In most situations I avoid using epoxy like the plague. It is completely irreversible making it unsuitable for most conservation work. If you make an error in reassembly or the piece shifts as it cures you are left with no options for realignment of the joint.

While it should never be used in a cut joint, occasionally when a section is broken in an area that needs structural stability, it has is purposes. With this repair, the leg is delicate and holding up a 6 foot long mahogany sideboard. The use of the dowel will add strength (that 6:1 ratio) and keep the joint true and square until cured. Other options would require replacing the leg or removing so much of the original material as to disfigure the piece.

mea maxima culpa...