Master Luthier Otis Tomas

Now the guitar is ready to take for a test run. I always like to string it up before giving it the final touches and cleanup before varnishing. This is the time to check it all over and make any changes that might seem necessary. A set of Waverly tuners is installed in the peghead, and after notching the nut and bridge, the guitar is strung up.

I let the guitar settle in for a few days, playing it and taking in my first impressions, and tweaking the action a bit. It has a nice warm liquid tone and quite a bit of power as well. I am quite favorably impressed. I now give the whole instrument a final scraping and sanding, playing and listening all the while. I slightly loosen up the recurve area of the plates feeling for flexibility and listening for the tone to open up a little more. I use mainly my hands and ears, but if I want to double check the thicknesses as I go, I can use my Hacklinger Guage, a magnetic caliper that allows one to measure the plate thicknesses of a closed instrument. I will work on this off and on over several days, alternating between playing it and working on it until I am satisfied that it is done, and then I will take the strings and tuners off, and give it the final sanding to ready it for varnish.

I have had several days now to play and enjoy the guitar, so now I reluctantly strip it back down and start the finishing process. I like to use an oil resin varnish. It is what I am used to from my violin work, and I think has everal qualities that recommend it. It is tough and flexible, extremely durable, relatively unharmed by sweat, moisture, or solvents, and it looks good. It gives an appearance of depth to the wood, especially on the figured grain, and the process and materials are comfortably low tech and simple.

I start by cleaning the guitar up and giving it all a light sanding with fine sandpaper. I am going to start with a sealer coat of some materials I find upstairs in my varnish room. I mix a bit of thick heat bodied linseed oil and polymerized turpentine and thin it with a little turpentine spirit, then rub this into the surface with some extra fine pumice. The oil and resin will sink into the grain and bring out the figure nicely. It is slow drying enough that it allows plenty of rubbing and manipulation while drying in a few days as a varnish in the wood. The pumice will not only help smooth the surface, but the fine particles will help seal the pores and end grain cells of the wood, making a more impenetrable surface for the subsequent coats of varnish proper. Although the pumice looks like a bright white powder in the open air, when the particles are surrounded by the medium of oil and resin, it becomes for all purposes invisible. I will hang the guitar up for this first coat to dry for a few days out in the bright sunshine if the weather is good, or else upstairs in my ultra-violet light box.

I now have the first couple of clear varnish coats on the guitar. I have used a light varnish of copal resin and linseed oil and here I have rubbed it down to smooth out any specks or brush marks. These first coats will finish the sealing of the surface and complete the filling of the pores and endgrain of the wood.

I will continue with additional coats on the top and neck, but I want to shade in just a little more color to the maple of the back and sides. For this I will use several thin coats of a dark amber varnish. The rich color of this varnish comes from the cooking of the amber. It gives a nice natural brown with just a hint of red. These very thin coats are not meant to give a dark finish to the wood (I want the beauty of the wood to speak for itself). I want to give it just a hint of color and a sense of highlight and shadow. I use no artificial driers in the varnish, so patience is important in letting each coat dry thoroughly.

While I wait for the varnish to dry, I turn to my next project, which I will give a hint of here.