The subject chair is a casualty of the larvae of the common furniture beetle, aka ‘woodworm’. At the top of the front right hand leg the larvae have eaten away sufficient timber to reduce the cross sectional strength to a catastrophic level.
The common furniture beetle seems to be attracted to Walnut, possibly due to its scent, and sees it as an attractive place to lay its eggs and woodworm damage is common in Walnut furniture. When the eggs hatch the larvae head inwards away from the light feeding on the timber for between two and three years and in this case much of the structural strength had been eroded. The exterior surface may show little sign of infestation until the larvae mature into adult beetles when they exit by boring out.
On examination of the adjoining pieces it became clear that the damage was fairly localised and the remainder of the leg was sufficiently strong enough to be able to withstand a repair rather than the more expensive task of making an entirely new leg. It was therefore decided to make a replacement section for that eaten away.
There were no signs of any live larvae and it was thought that the infestation was historic. However it is considered good practise to treat the remaining components with a chemical woodworm killer regardless and this was duly performed.
The design of the leg is such that there exists convenient points at which to cut away the damaged wood in order to create new flat surfaces to accommodate a replacement piece without it being noticeable. A new ‘bobbin’ shaped section was therefore turned on the lathe including a mounting spigot at each end. Mating holes were bored into the existing pieces of the leg to accommodate the spigots.
Before gluing the new section in place it was necessary to adjust the colour of the new Walnut timber because once polished it would be much darker than the faded original. The colour was removed using concentrated Nitric acid and heat, a rather hazardous process requiring much care. Having achieved the new base colour the section was glued in situ and coloured and polished to match the original timber. Small areas of gilding were restored where these had been damaged.
The chair now has a new lease of life!