The following notes were taken by Jason Viseltear at the 2008 Oberlin Violin Making Workshop. Mr. Scott did extensive varnishing demonstrations during the 2 week workshop. Jason Viseltear took comprehensive notes throughout and has allowed us to post them on our site.
1) Preparation of the wood:
Scrape the plates. Wet to raise the grain one time, to minimize swelling the wood later. Then one final scraping with a soft scraper or horsetail, to take off the raised grain and create a burnishing effect.
2) Tanning:
Tan instrument for 5-6 days in the light box. This tends to help the spruce more than the maple.
3) Imprimatura Dorata Primer
Apply with a 1" x 1½" household sponge. 2-3 coats on maple and 3-4 coats on the belly with 30 minutes between coats. Just prior to priming the top and end grains, turpentine is rubbed in evenly to prevent the primer from shooting into the end grain. One can put turpentine just prior to each of the subsequent coats on the belly as well. [Primer 1 will reach a saturation point after 2-3 coats, whereas Primer 2 will continue to darken and color wood with repeated coats.]
4) Imprimatura Dorata Sealer
After last coat of primer is applied, wait two hours until dry and add 1-2 coats of Magister sealer. This acts as a window into the wood. The sealer should be a controlled application so that no excess is left on the surface. It should have no body and not sit on the surface. Sealer is applied before exposing to UV light. It is a thin copal varnish and is brushed on thinly and then rubbed off.
5) UV Exposure
Expose to UV as long as you like. Overnight is all that is necessary. A diluted sealer and pigment combination might be used at this time if more color is desired in the flames of the maple.
6) Mineral Ground
Mineral ground is Magister Vernice Liquida and pumice for the belly. Add colored varnish to this mixture to control the color of the ground on the maple. The color should preferably be similar to the color of the subsequent varnish layers. A note on preparation: The pumice should be mulled in the varnish until it clarifies. The idea is to put it on, rub it in, and the rub all of it off the surface. Ladle on with a pallet knife, then spread it with a credit card (or other flexible plastic scraper) acting like a squeegee. Then rub it in with a white 3M medium grit synthetic sanding pad. Clean up any build-up before it dries, especially if in a hard to reach spot. Final polish the surface with a heavy canvas rag while wearing good latex or Nitrile gloves for a good grip.
6) UV Exposure
Dry in a light box overnight.
7) Repeat Mineral Ground
8) Varnish
3-4 gram of varnish for violin plus one drop of siccative per gram. The amount of drier (2-3% per varnish) will speed the varnish drying time 1-2 days. Mix it on a glass with a pallet knife. May mix something dark (i.e. lamp black, Van Dyke brown, or a color lake such as Lacca Rubia) into it at this time, especially if it is a Brescian model. Once it is on the instrument, rub cross grain to highlight the reed lines. This coat should be slightly thinner so that this ground enhancing effect will be best achieved. Small deposits of the varnish are moved from the glass plate onto the instrument with a pallet knife and then moved around the instrument with a pad, tamping it into place. Otherwise it might be moved from the glass to the plate with the pad itself. The pad is a prosthetic foam from a prosthetic supplier. Be careful to pad it on with a rolling motion- a pulling motion may pull off varnish. Once the varnish is padded on, it can be rubbed with fingers cross-grain to give some texture along the reed lines or padded with the hand for some pre-antiquing/ shading.
9) UV Exposure
Leave it in the UV box at night and take out of the box during the day. 6-12 hours in and 6-12 hours out of the box for full, thorough curing.
10) Repeat 2-3 color coats
11) Patina
Introduced between 2nd and 3rd coat if desired. Prepare the surface with a moderate sanding with microesh. If antiquing, dents and scratches can be introduced gradually at this point. With a judicious application of sepia water color, apply over an area of the instrument, rubbing until it evenly glazes the instrument. This should dry immediately, at which point, proceed to polish off all the dull glaze, cross grain and then circular, keeping your fingers clean enough of water color not to leave dirty deposits. You will notice there to be a delicate balance between pressure and friction which accomplishes this correctly. If you get the balance right, it polishes, creates a patina, and makes micro deposits of water color that will imitate the accumulation of dirt, smog, etc. Varnish can be applied immediately after this procedure. This can be repeated another time if minimal antiquing is required, otherwise tube colors in oil can be used for a heavier application of dirt for that effect if desired.
12) Final coat
Vernice Liquida (or a clear finish varnish) is used to apply a clear glaze. This can later be rubbed out/ French polished.
|