Usually my choices are towards wood and materials that are historically and geographically suitable. Sometimes for specific instruments tropical wood proves to be of good sound and stability.
Synthetic products such as industrial glues or varnishes are avoided. Natural glues are flexible and strong enough to hold while the wood joints accommodate to the humidity of the environment, and are better suitable for the restoring practise, being the object a modern instrument or a museum piece. Rabbit skin glue is used for the joints where flexibility is needed, and bone glue for the stable joints.
All soundboards are made with European Spruce. Good-quality pieces are easier to cut and better for carving. And I enjoy carving. Neutral parchment in different shades and thicknesses is used for the guitar, harpsichord, guittern and vihuela roses.
I make my own varnish with pine rosin, using a 30-hour cooking process, sun-dried linseed oil and pure turpentine. For the dark-brown coloured varnish, iron oxide is added during the preparation, as in the traditional recipes, through the use of rusty nails in the mixture. The red colour may be obtained with pure madder pigment.