Varnishing Process for the 16-1/2″ five-string Viola:

All Smoothing and Varnish-prep is done:

When I last posted, the final woodwork had been completed. I had twice wetted down the wood, to raise the grain, and scraped and sanded away the rough raised grain. The wood was stable enough to commence the tanning process.

After the wood is smooth, there will be:

1. a tanning treatment,
2. a mineral ground treatment,
3. a sealer, to lock the mineral ground in place, and
4. finally, the varnish itself in a series of 6-12 coats, depending on color.

Tanning the Wood

People who live in very sunny regions (New Mexico, for instance) need no light booth: they simply hang their instrument out in the sun for a few hours and it takes on a deep yellow-tan color. I live in Oregon. Western Oregon, between Portland and the coast. We are more likely to achieve a patina of bird-droppings than a sun-tan, if we hang instruments outdoors. (Sigh…)

So, a number of years ago, I bought an old cabinet, about seven feet tall, lined it with aluminum foil as a reflector, wired it with a strong UV source (two 48″ fluorescent UV tubes in a shop-light fixture), and I hang my instruments in it overnight. To heighten the effect, I brush on a coat of very diluted Sodium nitrite and let it dry before I expose it to the UV. This works pretty well, and I have pretty much adopted it as a normal pre-varnish treatment.

Tanned front of 16-1/2" 5-string viola — Tanned front side of the 16-1/2″ five-string Viola.

16-1/2" Five String Viola tanned back side. — Tanned back side of the same instrument.

Mineral Ground:

Years ago, an excellent luthier in Europe posted a detailed explanation of why and how he employs a mineral ground in his instruments, to improve projection. I tried it (because, “if it is good enough for Roger Hargraves…”) and immediately started getting better reviews on the sound of my instruments.

So…obviously, that became part of my process, as well. I use gypsum powder, suspended in coffee (gotta wake up the tone!) so as to achieve a little deeper color in the same move. I rub it in vigorously, trying to get the particles of gypsum to actually penetrate the pores of the wood, then rub off the excess with a rag, before it is fully dry. When it is dry, it obscures the grain, and turns a chalky white color.

Mineral ground drying on 16-1/2" Five-String Viola. — Mineral ground drying on 16-1/2″ 5-string Viola. (5-string bass beginning in background.)

Mineral Ground is dry on the 16-1/2" Five-String Viola. — Mineral Ground is dry. I will sand off any excess mineral, and then apply the sealer.

Sealer

The sealer, in this case, is simply rosin, dissolved in turpentine and alcohol. The mixture soaks into the wood, causing the mineral ground to become transparent, then the solvents evaporate, leaving the rosin in the wood. The mineral ground will never again be visible.

Varnish Beginning

When the sealer is dry, I sand lightly, using 320 grit, to remove any lumps I may not have seen, and then I am ready to begin varnishing. I always begin with two base-coats of very yellow/gold varnish, so that the gold color will shine through the darker color coats.

16-1/2" Five-String Viola with Two coats of yellow varnish, side and front view. — Two coats of yellow varnish, side and front view.

16-1/2" Five-String Viola with Two coats of yellow varnish, back view. — Two coats of yellow varnish, back view.

I like the way the European Maple and Spruce are shining through the varnish. I think they will sound great, too. Tapping on the corpus, it sounds as though it will have a big, deep voice.

I will follow the completion of the varnish process in a later post.

Thanks for looking.

Varnish Progress on the Commissioned 5-String Fiddle

Varnish Procedure for All my Instruments:

Complete all scraping, shaping and smoothing: varnish preparation.
Wet the instrument down to raise the grain, then
Lightly sand with fine-grit abrasive, to remove rough bits of raised wood.
Rub in a mineral ground, then use a rag to remove excess.
After the ground dries, sand lightly again, to remove any rough excess mineral.
Seal using turpentine and rosin.
After the sealer is dry, begin adding coats of varnish.

Following the above format, here are the results:

Dried Mineral Ground, on the Five-String Fiddle, compared with varnished instruments. — Dried Mineral Ground, compared with varnished instruments.

Five-String Fiddle front view with sealer — Front view with sealer…mineral has disappeared.

Five-String Fiddle Side view with sealer — Side view with sealer…the grain is visible; the ground is transparent.

Five-String Fiddle back with sealer — Back with sealer; the grain is very visible, the ground has disappeared.

Now the varnishing begins!

The mineral ground was intended to close all the open pores in the wood so that the varnish will not saturate the wood. Then the sealer locks the mineral ground in place and causes it to become transparent. (Think “wet t-shirt material.” White stuff becomes transparent when wet, as a rule.)

So, now the varnish further seals the wood and begins to add gloss and protection from moisture, dirt, etc. And, if we do it correctly, it will add the color we want, as well, without losing transparency.

I have used both oil varnishes and spirit varnishes. I believe the old masters used oil varnish, but currently, I have moved to spirit varnish. Perhaps one day I will use oil varnishes again

Spirit varnish dries so rapidly that I can usually apply four coats of varnish the first day. So here is the fiddle with four coats of spirit varnish:

Five-String Fiddle with four coats varnish front view — Front, with four coats varnish…still pretty yellow.

Five-String Fiddle side with four coats varnish — Bass side with four coats of varnish: Too much contrast between side and front plate.

Five-String Fiddle back plate with four coats of varnish — Back plate with four coats of varnish… looking pretty nice!

Leveling the varnish

So, then, after the first few coats have dried hard, we sand lightly to remove brush marks, sags, drips, etc. and begin to add color coats. Usually, I have a pattern of shading I use, to emulate light “wear” patterns. This one has very little of that.

Five-String Fiddle Final color front plate — Final color front plate…the light patch on the upper left is a reflection.

Five-String Fiddle Final color treble side — Final color treble side: notice that the front and side match nicely, now.

Five-String Fiddle Final color bass side — Final color bass side.

Five-String Fiddle Final color back plate — Final color back plate.

Five-String Fiddle Final color bass side scroll — Final color bass side scroll.

Five-String Fiddle Final color treble side scroll — Final color treble side scroll.

Final Finish Work

So, now we will let the varnish thoroughly dry, and harden; after which there may be retouching and minor changes to make, but the main focus will become set-up after that. (In case anyone is interested, the customer has been kept abreast of every step in the build, and is getting quite anxious to take possession.) 🙂

Thanks for looking!

Tag: Varnish Process

16-1/2″ 5-string Viola Varnish Sequence