From The Ground Up

Since time immemorial, makers have searched for the perfect varnish recipe, and take great care of the ground – but often fail to realise the importance of preparing the wood first. Christopher Jacoby gives a crash course in ‘ground prep’

- Christopher Jacoby

There is enough lore associated with the varnishing of violin-family instruments to fill an encyclopaedia. The received wisdom is that, with the application of a few thin coats of refined oil, an instrument will outlive its owner by many hundreds of years, as long as it continues to sound good enough for subsequent generations to care for it. But those thin layers of pigment over the wood are not the heart and soul of fine instrument varnish. The preparation for the ground varnish (the ‘ground prep’) – and the sealing coat of ground itself – will make or break the look of your finished instrument, and maybe the sound of it as well.

A great ground can be arresting. It can illuminate all the years of the instrument’s history, shining through the numerous layers of varnish and patina above it, a testament to the incredible intricacy and heritage of a piece of wood only a few millimetres thick.

The purpose of the finished ground varnish is to prevent any damage to the bare wood beneath, to enhance the natural beauty of the wood, and to turn the open pore structures of the exposed wood into a material that will enhance both the quality and projection of the instrument’s sound.

‘Ground prep’ is anything you put in or on the wood to protect, beautify and enhance its natural colour, before applying a base (ground) layer to set thicker varnish on top of. Yet the most important part of ground prep is getting the wood dark enough in the first place. The question for makers is: how dark is dark enough? One of my mentors once gave me a good rule of thumb, as he was looking over my shoulder at a violin I thought I’d ruined during ground prep (the woodwork was the colour of a charred cream cracker, while the figure was burnt and the surface less reflective). ‘Go ahead,’ he said. ‘Once it scares you, it’s dark enough.’