More Plowden Progress

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More Plowden Progress

Graduation

Graduating hard maple can be a tough, laborious job. Besides, there is always the possibility of carving too deeply and ruining the plate. So, I try to cut the risks by creating a “map” by marking the thickness every few centimeters, and then carving the “dots” until each “dot” is about the thickness I want. Finally, I connect the “dots”, using planes and scrapers, checking for thickness as I progress.

Creating the dots. The circled numbers are already the correct thicknesses.

Grafted Scroll and Neck-Set

Once the graduations are complete, and the inside of the back plate has been scraped completely smooth, I install the label and I am almost ready to close the corpus. In this case, however, I also had decided to use the scroll I had carved, but graft a new neck to the scroll, as the original neck was too thin: so there was a good deal more work involved. Here is the grafted neck, partially shaped, with the completed back plate:

Completed back plate with neck-grafted scroll. The heel was still not shaped.

I had been anxious to complete the back plate, and had not yet set the neck. So I completed the neck and installed the fingerboard.

Next I set the neck, so that the angles were all correct.

Neck-set, front view. The mold is still in place.

Neck-set, side view. Notice that the neck heel has not been trimmed flush, yet.

Closing the Corpus

Then I removed the mold, and installed the inside linings on the back edge of the ribs, shaped the linings and the blocks, flattened the back of the garland, and installed the back plate. I use spool clamps and a single large spring-clamp to close the corpus. My wife thinks the spool-clamps look like old-fashioned hair-curlers.

Closed corpus with spool clamps and a spring-clamp.

Trimming the Button and Neck Heel

Once the glue was dry, I removed all the clamps, cleaned off any glue that had squeezed out of the joint, and trimmed the button and heel. The dimension from the juncture of the top edge of the front plate and the side of the neck heel (from each side) to the very center of the curve of the heel, should be right at 26 mm. You can see the two marks I laid out with a compass, testing that distance: it was still a little too high in the center of the curve, so the neck needed to be trimmed a little more.

Purfling the Back Plate

Once the neck-heel and button were trimmed, I still had to perfect the outline of the back plate, making certain that the overhang was even all around, as much as possible. Then I laid out the purfling slot, using a purfling marker, and began incising the outlines of the slot.

Incised purfling slot. It will be corrected, and fine-tuned as I work, and look good with the purfling.

Next I cut the slot out, using a small knife and a purfling pick, then dry-fit the purfling, after bending it on the bending iron. Finally I glue it in place, using hot hide-glue.

Edge-Work

I marked a crest-line, about 1.6 mm in from the outer edge, then used a gouge and scrapers to carve the channel, and fair it into the plate surface. The edges were all still quite rough,and crude, so I began shaping them, using a small plane, and a half-round file, then sandpaper to get a smooth edge all around. I don’t use sandpaper much, but this is one place where it is appropriate.

Trimmed purfling, smoothed channel, and edges taking shape.

The front edges have to be finalized as well.

Finishing Process Begun

Once all the varnish preparation is complete, I brush a coat of coffee all over the instrument, to tan the wood a little, and raise the grain. When that is dry, I sand off most of the raised grain, using 400-grit sandpaper. This ensures that the grain will not raise too much during application of the spirit varnish, later. Afterward, I rub in a coat of gypsum in a coffee suspension, to fill the pores of the wood with particles of the mineral. This keeps the varnish from saturating the wood, and possibly dampening the sound.

Mineral ground drying. See how it obscures the wood? that goes away when the sealer is applied.

Back with sealer. — The sealer renders the mineral ground transparent, and it will never be visible again.

I expect that, by tomorrow, the sealer will dry sufficiently that I can begin varnishing. I am getting anxious, as the show is a week from tomorrow, and I am far from completing this instrument.

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March 1, 2018March 2, 2018

Varnish Process

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Varnish Process

Sealer Coat is Dry: Start Varnishing!

Since the sealer was dry, I gave the violin a careful rub-down with worn 400-grit paper, and began to add varnish. I am using a spirit varnish, the first coat of which was a yellow varnish, which I had actually hoped would be a little more “amber” in color, but I think it will be OK.

First coat of varnsih on back plate. — First coat of varnish on the Back plate.

1st coat varnish on side. — First coat of varnish on the Side.

First coat, Front plate. — First coat of varnish, on the Front plate.

2nd Coat of Varnish

The first coat of varnish was really only intended to lay down a yellow under-coat, and I am satisfied that it accomplished that purpose. From here on out, though, I will be trying to lay down more color in the areas indicated, to try and match the original after which I am modeling this violin. So, here are coats two and three. Notice that I leave some areas light, as the original violin has fairly severe wear in those areas. (If you are interested, click here to see photos of the original.)

2nd coat on side — 2nd coat of varnish, on the Side.

2nd coat on back. — 2nd coat of varnish on the Back.

3rd Coat of Varnish

And, a third coat, in the same manner:

3rd coat, front. — 3rd coat of varnish, Front plate. The light was a little better, so it looks brighter.

3rd coat, side. — 3rd coat of varnish, Side view.

3rd coat, back. — 3rd coat of varnish, Back view.

4th Coat

The first few coats are thin enough that it is difficult to see the changes…but it is gaining a little more color and gloss.

4th coat, side view. — 4th coat of varnish, Side view.

4th coat, Back view. — 4th coat of varnish, Back view.

5th and 6th Coats

It is pretty obvious, now, even on the ribs, that certain areas are getting less color added. As I explained above, those are the areas that typically get the most wear, so, to imitate the wear patterns on the original instrument, I am minimizing the color added to those areas.

Also, I have been making the varnish coats quite thin, right now, trying to adjust the color early, instead of trying to fix it later…so, from here on, I posted the pictures as I saw relevant changes, rather than after every coat of varnish. I also switched over to a more intensely colored varnish for the 5th and 6th coats:

6th coat, front view. — 6th coat of varnish, Front view. Lots of changes still to come.

6th coat, side view. — 6th coat of varnish, Side view.

6th coat, back view. — 6th coat of varnish, Back view.

Starting to look closer to what I had in mind. 🙂

Final color coats, and two clear coats

I gave a careful look to the poster, again, and tried to get the “wear areas” closer to the original. It is still far from accurate, but it is beginning to at least have the “flavor” of the original. My color is still too bright, and some areas still too light, but it is getting closer.

Front, nearing completion of color coats.

Side, nearing completion of color coats.

Back, nearing completion of color coats.

“Dirt” and “Age”

There were a few areas to which I wanted to add more color…and to rub some pigment into the grain, to emulate dirt. (I had already rubbed in some real dirt, but it wasn’t very convincing-looking.) Then, I locked it all down with a clear coat or two, and will polish it to completion. But this is pretty much the final color:

Back, with final color, “dirt”, and “age.”

What’s Next?

The next thing will be to re-fit the fingerboard, dress the fingerboard, and begin set-up. I will continue to address “polish and finish” issues as I see them.

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February 21, 2018February 22, 2018

Sealer Coat

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Sealer Coat

Cleaning off the Excess Gypsum

I used scrapers, very gently, in tight corners, and very worn 400-grit abrasive paper, more aggressively, on the easily accessible areas, to remove all the loose, or overly thick areas of the gypsum pore-filler from yesterday. It took longer than I expected, but this was the result:

You can see that the grain is somewhat obscured, and the color is quite light. I am wondering whether I did not succeed in rubbing the gypsum into the wood, as thoroughly as usual. Usually, the color has been nearly chalk-white. I can see the gypsum in the wood, though, so I am going to press on with the sealer coat.

Sealer Coat

This time, the sealer consisted of ordinary rosin in a solution of “pure spirits of gum turpentine”. I probably should have made it a little thinner. It was about like light syrup; so, afterward, I dipped the brush in plain turpentine, and went back over the instrument to help the stuff penetrate a little better. The turpentine will all evaporate over the next few days (I hope), leaving only the rosin, solidifying in the pores of the wood. It is always impressive to see just how completely the gypsum disappears, under the sealer.

Front plate and side, with the sealer coat applied.

Different angle — Different light angle shows the curl in a more attractive mode.

Now What?

Until that sealer dries completely, I will have to find other things to do. But it is hanging in a warm room, so it should dry rapidly.

After that, It will be varnish coat after varnish coat, until it it is all done. Then the final set-up can occur.

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February 20, 2018February 21, 2018

Beginning of the Finish

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Beginning of the Finish

Gypsum Mineral Pore Filler

A world-class luthier in Germany (Roger Hargraves) shared this publicly…he accomplished it a little differently, in that he prepared his gypsum by hydrating plaster of paris very thoroughly, and using the carefully washed fines as his filler. I used the finely-ground gypsum available in gardening stores, stirred it into a suspension of strong coffee and ethanol (only there to keep the coffee/gypsum mix from developing mold, sitting on the shelf), and brushed and rubbed the mixture into the wood of the violin. Then I rubbed it back off, using a soft rag, getting as much as possible back off while it is still wet. The goal is that the fine particles of gypsum will plug the pores of the wood, so that the subsequent coats of varnish will not penetrate into the wood. I can’t say whether my method works anything like that of Mr. Hargraves. Perhaps someday I will try something else. But for now, that is what I do.

First, I removed the fingerboard, and did some miniscule corrections to the scroll, pegbox and button. Then I painted on the stirred-up suspension, coating everything except the handle area of the neck.

Gypsum mixture on the back...still wet, but already beginning to dry. — Gypsum mixture on the back…still wet, but already beginning to dry.

Lots of uneven coloration. I’m not certain why, and it may present a challenge during varnishing. Not my usual experience.

Gypsum on back-- dry. — Gypsum on back– dry. Notice how the flame is obscured.

I’m not certain why the spruce acted the way it did. I had wetted it with coffee before, without any mishaps. I am wondering whether I somehow compressed certain areas, in re-scraping, and they responded differently. I can’t be sure. But I have enough experience with varnish that I am not worried about the outcome. (After all, it was a very old, worn instrument I was copying.) 🙂

What’s next?

So…the next step will be to rub off all the excess dry gypsum, and clean up any rough areas where the grain may have raised again. (I’m not really expecting any, but I will be looking for them. Then, tomorrow evening, I hope to apply the sealer that will lock in the gypsum. It is always a little astonishing to me, to see the grain and flame suddenly “pop” out and become very visible. The gypsum becomes completely transparent, and is never evident again.

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February 19, 2018February 19, 2018

Final Shaping and Scraping

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Final Shaping and Scraping

The Channels and Edges

The last time I posted, the back purfling had been installed, but the back channel had not been begun, nor were the edges trimmed and rounded. I drew in the edge crest line, just as I did on the front plate, and carved the channel with a gouge, then began scraping the channel and fairing the curve of the channel up into the curves of the arching.

Beginning Channel — Beginning the channel

Sample corner, after preliminary scraping. — Sample corner, after gouging and preliminary scraping.

After I had gone over the entire instrument under a low-angle light, looking for “lumps and bumps” (any little discontinuity that will be visible under the varnish…and they all are), I wetted a cloth with black coffee, and rubbed the whole instrument down with the damp rag. This accomplishes two things: it begins to lend a very light yellow cast to the wood, and, more importantly, for now, it raises the grain, so that every little splinter that was pressed down by the scraper, instead of being severed and removed, will now stand up and be visible…easy to find and remove, using either a very sharp scraper or, eventually, a very fine abrasive. (In general, I avoid abrasives, because I am not convinced that the surface left by fine abrasives is the same as the surface left by a sharp scraper. But, as a means of smoothing between varnish coats, or just before varnishing, I feel it is viable. I also use it on the edges of the plates…especially the spruce.)

So…here is the instrument, dampened with coffee. When the coffee is dry, I will continue the smoothing and shaping process.

Coffee rubdown. When it dries, it will leave a pale yellow stain…very slight.

coffee surface — You can see the pale yellow color, and the shape of the corners. The surface actually feels rough, now, though it looks smooth.

Scroll with coffee dampening. Notice the splinters on the edge of the curves.

Front of scroll. See how rough the wood looks…lots of scraping still to come. And maybe some abrasive smoothing.

Back plate with coffee stain.

Final Scraping of the Whole Surface

Once the coffee was completely dry, I went to one of the few places in the house where I can get a fairly dim, very low-angle light across the violin, and went over the instrument, intently searching for either rough patches or places where the smooth continuum of the arching is interrupted by a ripple, a ridge, or a bulge, etc. I want the arching to be as close to perfect as possible, and every transition from curve to curve to be flawlessly smooth. (I have never actually achieved this level of perfection, but that remains the standard. Every time, however, after the varnish is applied, I find things I missed.)

After scraping every surface, very gently, with a sharp scraper, until all seem to be very smooth, I rub the instrument down with coffee again. Usually, this time, the grain will not raise as agressively as before, because I did not press the grain with the scrapers but just “brushed” the surface, taking off mere dust, but leaving the channels and transitions looking finished and shiny-smooth. This is an important time to watch for anomalies of any sort, because once the varnish is applied, it is very difficult to go back and “fix” things. Several of my earlier instruments have an odd pattern of dark stripes in the upper front bass bout, following the curve of the outer edge, and adjacent to the neck. These could have been avoided by careful scraping under a low-angle light. They remain as permanent record of my “learning curve.” (sigh…)

Here is how the instrument looks, ready to begin the finishing process:

Front plate, ready to begin finishing process — Front plate, ready to begin. (I will remove the fingerboard first.)

Detail of Center bout, ribs and corners.

As you can see, there are are a few things I will probably want to touch-up just a little more before I actually varnish, but, overall, I am satisfied that I am ready to move forward. There will always be little things I change at the last minute, but that is just my nature.

What’s Next?

So…the next “big” thing is to remove the fingerboard (easy to do…I only held it on there with three dots of hide glue), and then I will rub very fine gypsum mixed with coffee into the whole instrument, and rub it back off before it dries. The goal is to fill the pores, so that the varnish will not saturate the wood.

After that is dry (and it will look chalk-white), I will apply a coat of sealer (rosin dissolved in turpentine, at the moment), to lock the gypsum down, and further seal the pores. After that; varnish time!

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September 27, 2016September 27, 2016

Finishing Sequence Part Two

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Part Two: Beginning Varnish.

Sealer

When we last posted, I had just applied the sealer coat, and it was pretty fresh, still.

The sealer does lighten a little bit as the turpentine evaporates…and, of course, the smell changes a lot. I happen to like the smell of turpentine, but it is pretty overpowering when the sealer is still fresh. Once the sealer was dry, I took a few more photos, then did some varnishing. I think you can see the difference, here:

Dry Sealer

Beginning Varnish

But then I began the varnish. I usually try to lay down a golden base-color, and then add whatever other color I am working toward. I have ranged all over the board, trying different colors, but usually I end up in the browns or red-browns. I tried a really red violin with a student who demanded it, and he was thrilled with it…I was not. 🙂

So here is the viola after two coats of yellow-gold varnish.

fist two coats of yellow varnish — This is the first two coats… Not a lot of change, initially. Varnish takes a while to build up a good film.

Side view with two coats of yellow-gold varnish.

viola with two coats of varnish — Back of viola with two coats of yellow-gold varnish.

I let it dry for a few days (partly because I had a great deal of other responsibilities that week), and then sanded it gently with worn 400-grit abrasive, rubbed it clean with a dry rag, and added another two coats of varnish:

Subsequent Base Coats

Viola with four coats of yellow-gold varnish. — Viola front and side, with four coats of yellow-gold varnish.

Viola back with four coats of yellow-gold varnish. — Viola side and back with four coats of yellow-gold varnish.

The appearance changed a lot more dramatically with those coats, didn’t it? The colors are getting richer, and the finish is much more glossy. I used the flash on these last two photos, so, to stay consistent, I will try to use it (and the same background) on all the remaining photos of the varnish.

Color Varnish and (Maybe) Antiquing

The next step will be to decide just how far down the “antiquing trail” I want to go, this time. I will unquestionably do at least a little…but I really like the look it is developing right now, so I want to be careful to not lose it. (The neck stain and seal is the very last thing to go on, just in case anyone is wondering. I will explain that later.)

At the very least, I will begin adding some red-brown varnish, to darken things up a little. I will most likely do at least a gentle shading toward “antiqued,” but I am leaning toward minimalism this time. Nothing drastic.

We’ll see. 🙂

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September 22, 2016September 23, 2016

Finishing Sequence Part One

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Beginning of the Finish

We looked last time at the viola with the edgework incomplete, and final scraping not done.

Edgework

Here is the viola with the edgework done. Notice that the outer edges have been rounded inward to meet the edge crest, so that the junction between edge crest and purfling channel makes a clean ridge around the perimeter of the viola. This is just something I do, because I like it…as far as I know, it has no functional value. Many old master instruments have a much less clearly defined crest.

Coffee Stain and Re-smoothing

Then I wet the fiddle down with coffee, to raise the grain and add some color. One result is that my edgework all needs to be reworked with a small, sharp scraper. The other is that the whole instrument needs to be re-sanded, using 400-grit sandpaper. The water in the stain raises the grain, so that every random fiber that is not closely tied to the surface will swell, and raise up, making the whole surface very rough. So I deliberately raise the grain, and then scrape or sand off the rough surface. Using a very sharp scraper, very lightly, just “brushing away the rough stuff” is probably the best way to do this. I use a scraper for the areas where I want detailed, clean edges, and 400-grit abrasive paper for the broad surfaces. I perform this step at least twice, before moving on to the mineral ground. The result is a surprisingly light, yellow-tan color, all over. Almost just a cream-color. It will darken up nicely under varnish, though, and not glow white from under the varnish.

Come to think of it, the above photos already have the coffee stain, too. I forgot to take photos of just the edgework, I guess. So–those photos are right before I applied the mineral ground.

Mineral Ground

This is a suspension of very fine particles of gypsum…in a coffee-solution, because I still want to add more color, if I can. Other people use other minerals–finely ground mica, finely ground glass, microscopic beads of glass, clay, volcanic ash or other non-organic nano-particles. Some omit this step entirely. Roger Hargrave shared this as having had an important effect on his sound, so I have tried it, for the last several instruments, with what seem to be positive results.

I keep the solution well-stirred-up, and brush it on liberally, then rub it into the wood with my fingers, as vigorously as I can. Finally, I wipe off as much of the excess as I can, using a rag. The stuff goes on looking brown, because of the coffee, but dries to a chalky-white film. I don’t particularly want it on the wood– I want the microscopic particles to fill the pores in the wood, so that the varnish will be less likely to soak deeply into the wood, and deaden the sound of the viola.

The ground dries rapidly, leaving the whole viola a chalky-white, ugly object. I go over the dry instrument, checking everything, and scraping or sanding off all the excess ground. When I can see the grain of the wood everywhere (though dimly) through the gypsum film, I apply the sealer coat.

Mineral Ground, wet...back view — Mineral Ground, wet…back view.

Ground drying — The ground dried rapidly– this was only about three minutes after the above picture.

Dry Mineral ground — Here it is, dry–without the flash. In daylight this is chalk-white. See how the grain is obscured.

Mineral ground dry front view — And the front– you can see the excess pretty easily.

Here, you can see the excess ground in the f-holes, and along the purfling.

All that excess gypsum had to come off. It took a while, but I got it ready to seal:

Viola front is ready for sealer– all the excess mineral ground has been cleared away.

Sealer–What kind?

Different makers use different sealers:

Some use a very thin varnish.
Some use Rosin-oil (I’m not even sure what it is….)
Some use shellac.
Some use commercially available sealers.

Currently, I am using a very thin mixture of pine pitch and turpentine, with a little alcohol. The alcohol and turpentine cause the mix to penetrate deeply. The pine-pitch goes into the wood along with the solvents, and remains there. It is interesting to watch the sealer going on…the chalk-white gypsum instantly turns transparent, and effectively disappears, leaving the natural color of the wood, along with whatever staining was added.

Without adding any color to the sealer, this would leave the wood a somewhat pale color. Usually, I have been satisfied to add color later. I added a little amber color to the sealer, this time, though, because my last instrument was a little too light-colored, initially, and I didn’t like the result.

The alcohol evaporates nearly immediately, while the turpentine takes a few days to evaporate, and (I am told) it leaves a bit of residue, as well. But that is OK. Turpentine is a natural wood extract, and I don’t mind it being in the wood.

The pitch dries in the wood, locking the gypsum in place, and sealing the wood against any other substance. Again, the pine-pitch is a natural wood extract, which eventually dries hard, and I don’t mind it being in the wood. Besides, it smells nice. 🙂

Here is the viola with just the sealer. I will show the varnishing sequence in the next post.

Sealed viola back — And…here’s the freshly-sealed back; again, using the flash.

The wood will change color just a little as the sealer dries. But it will never go back to the dull-looking finish where the grain is obscured again. The varnish I apply will enhance, not obscure the figure in the wood…I hope. 🙂

Varnish (coming…)

I use a spirit-varnish, currently, though I have used oil varnishes in the past, and undoubtedly will again. I will start off with a yellow varnish to enhance the figure in the wood, then use darker coats to finish. I use enough coats to get the color the way I want it, including whatever shading I choose to do, then add enough clear coats to give it the depth and sparkle I want. Usually 6-8 coats, I guess. I sand lightly after virtually every coat, to reduce any bumps, sags, runs, or brush-marks, as well as looking for brush hairs or bugs, stuck in the varnish film (it happens….)

Finally I rub the surface with extremely fine abrasive (12,000-grit micro-mesh), and then polish it all over, using the dry skin of my palm, or thumbs, rubbing hard enough that the varnish gets uncomfortably hot. This takes away the “glittery” look of the fresh varnish, and leaves the glow of hand-rubbed work. Pictures in the next weblog post.

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July 28, 2016July 28, 2016

Varnishing Sequence: Part One

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Varnishing a New Violin

Finishing Sequence: Sealer coat first

In the last post, I showed the photo of the violin with just the turpentine/pitch sealer coat in place, and not totally dry. Remember that this was applied over a coffee stain, and a mineral ground that I had rubbed into the wood.

When that coat was finally dry, I checked for any distortions (from the coffee stain, I guess) and corrected them with plain water, just moistening any low areas with a damp rag, and watching them come back to normal. Since I just barely moistened those areas, they stayed in the correct position after drying the second time. This has been a rare occurrence in my experience, but I was grateful that it turned out to be a relatively easy fix.

Then I sanded lightly with worn 400-grit, to remove any bits of loose debris and/or any little fibers of wood that had lifted above the smooth surface. I had already done this after staining (both times), but it always pays to go over things again.

First Coat of Varnish

The first coat on this instrument was a very blond spirit varnish; not my usual. I am not entirely pleased with the result, but it is acceptable.

first varnish coat — First varnish coat, side view.

Scond Coat: Darker Yellow

I sanded it lightly, again, and then applied a darker yellow varnish. Fortunately, spirit varnish dries very rapidly, so I can sometimes get two or three coats in one day, early in the sequence. As the varnish gets thicker, it dries more slowly. I assume that this is because it can no longer soak into the wood at all, so every bit of the drying has to happen from one side of the varnish film; but perhaps there is more to it than that. At any rate, as the instrument nears completion, I have to allow longer time for drying. The other side of the “fast-drying” coin (or two-edged sword) is that it is extremely sensitive to the next coat of varnish, as the solvent in the new coat can easily lift the previous coats, forcing me to completely start over, in some cases. I really need to be patient, and work carefully, applying many thinner coats, rather than fewer thick coats.

Second coat of varnish-- darker yellow-- side view. — Second coat of varnish– darker yellow– side view.

Yellow varnish second coat. — Lots of room for improvement, here– and that is how spirit varnish works. I keep adding color, and “evening things out” until it looks right.

Yellow varnish back second coat. — Yellow varnish back– still pretty pale-looking, after that second coat.

Third Coat: Red-Brown varnish

After the yellow varnish dried I began adding (several coats of) a darker red-brown varnish, allowing each coat to dry, and sanding lightly between coats, to make sure the finished result is good. This is the first coat of the red-brown varnish, so, actually the third coat, overall. It will get at least five or six more coats of varnish before it is done, but the differences become less and less obvious, as the varnishing nears completion. I am enjoying looking at the beautiful European maple and spruce. I ordered this wood from International Violin Company, in Baltimore.

third coat of varnish — Third coat, using red-brown varnish.

third coat of varnish on back — Back, with the third coat of varnish. (Quite an improvement isn’t it?) You can see the brush-marks in the varnish, but they will be sanded smooth before I apply the next coat.

The Plan:

As I continue to add coats of varnish, I am keeping an eye on the general “flavor” of the instrument. I may skip certain areas for several coats, to leave the varnish thin in those areas. I deliberately try to emulate the look of some of the more gently-used “Old Master” instruments. I am not attempting to “fake age”, so much as attempting to capture some of the charm and appeal of those intruments. If anyone has a question about my motives, all one has to do is check the label: every instrument is signed, numbered, and dated. The date on the label is the day I actually closed the corpus, so, perhaps a few weeks prior to final completion, but no more than that.

I also may switch back to a yellow varnish at some point, to shift the color back toward gold, rather than just a red-brown. And, occasionally, I have stripped everything back off and started over. As the original maker, I have that option. and, invariably, the result the second time was far better.

I will post more varnish photos as the violin nears completion.

Set-up:

Once the varnishing is complete, I will replace the Fingerboard and begin the final fittings and set-up of the violin.

Fingerboard
Saddle
Tuning pegs
Nut
End Pin
Soundpost
Bridge
Tailpiece
Strings
Chinrest

Hopefully, all of that will be covered in the next post.

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July 24, 2016

“Beginning of the Finish”

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Finishing My Newest Violin

Introduction:

For every violin, viola, five-string fiddle, cello or double bass I build, the finishing process is nearly the same. After completing the last of the purfling, the order is as follows:

Channel (the concave curve in which the purfling is nearly centered, but which must fair smoothly into all the other surfaces, concave or convex.)
Final edgework (making the outer edge (and inside of the plate) curve together into the channel and arching)
Varnish prep (final fairing-in of all curves and elimination of all bumps and unwanted ridges)
Water-based stain (usually two or three applications)
Mineral ground (one application)
Seal-coat (one application)
Varnish (numerous coats)
All set-up issues: saddle, fingerboard, nut, pegs, soundpost, bridge, endpin, strings, tailpiece and (on the smaller instruments) chinrest.

The Channel, and Final Edgework:

I scribe a margin around the entire outer edge, usually about 1.6mm in from the outer edge. This will serve as the “limit” for the channel. I cut the channel to the desired depth, using gouges first, then small planes and scrapers, bringing the smooth curve up to match the scribed limit. Then I file the outer edge so that it curves in from the center of the edge of the plate up to meet the scribed margin of the channel. The other margin of the channels are scraped so that they fair into the curve of the plates themselves. I true-up all my lines using scrapers, files, and very fine abrasives, and then I am ready for final varnish preparations.

On my last post, I had just completed the back purfling. That seemed a good place to “call it a night”.

Back purfling complete: the channel has not been started. You can see the sharp edge of the purfling in a few places.

Then I began preparations for cutting the channel, by scribing in the boundary line:

Scribed line, marking the edge of the channel.

Scribed pencil lines where the channel will go at the corners. (I didn’t use the flash on this one–that’s why the color is different.)

Beginning the channel cut. The purfling looks cleaner, as the rough, glued edge is gone. I also began shaping the edges.

Varnish Preparations

I have a particular spot on my basement stairs, where I can get a very low-angle, not-too-bright light source, which casts shadows across the face of the instrument, and makes is easy to see irregularities. So, the last thing I do is stand there, holding the fiddle and rocking it very gradually, to see any shadows that indicate a rough spot or an irregular shape. When I find one, I gently scrape it away with a very sharp scraper. I want to move as little wood as possible at this point in the build: I already have the arching and graduation just about exactly where I want them to be. This is strictly fine-touch finish-scraping.

Some people are very particular about not using ANY abrasives. Sorry– I do use them, in a very limited way, but only at the very last part of the build. The edges of the spruce plate, for instance, are so soft that a scraper is simply too aggresive for final shaping, especially after I raise the grain with my water-based stain (strong coffee, in my case…yes, and I drink the leftover “stain.”) So I use a very fine (worn 400-grit) abrasive paper to make the edges smooth and pretty. I also use it later, between coats of varnish, to make sure that no bits of dust, splinters, etc. can spoil the next successive coat(s) of varnish.

Channel complete...no flash. — Channel and edgework complete…no flash. The wood isn’t really this yellow– we have a fairly dark house, and the sunlight filtering through makes it look this way.

Completed channel, with flash — Same shot of the completed channel, with flash. This is pretty close to the real color at this point.

Coffee Stain

I use a coffee stain because it imparts a gentle yellowish look to the wood, without doing any damage to the wood. Many people use strong tea, and I have done so. Some have a particular tea they use, for the color they want. That is fine. Some have alcohol-based, color-fast dyes to accomplish a similar result. That is OK too. I’m just telling you what I do. People have sometimes asked whether I use de-caf or regular. I love that question: I say, “Oh I always use regular, to wake up the tone!” 🙂 (Riiiight…)

Mineral Ground

This is something I got from Roger Hargraves. He is a master luthier living in Germany, and he wrote an online book as he built a magnificent double bass. In it he explained why he uses a mineral ground, and what it is (it is effectively exceedingly fine gypsum dust, introduced into the wood pores in a liquid suspension. He used a very thin varnish as I recall…I used coffee, again. It dries slowly, is easily applied, and cleans up with water.) So, I apply the mixture with a brush, one area at a time, rub it in with my fingers, and immediately rub back off as much as I possibly can, using a rag. I do NOT want a thick layer of stuff on top of the wood– I want the pores themselves to be filled with the particles. I coat all areas except the “handle”portion of the neck in this manner. Supposedly it leeps the varnish from saturating the wood, thus avoiding overloading the wood with varnish and deadening the sound. Does it help? He says it does, and I know for a fact that he did it…and I saw the bass in person, last year at the International Bassists Society convention, in Ft. Collins, CO.

The ground dries chalk-white, in spite of the fact that I used coffee for the liquid. I sand it gently to remove any excess gypsum (there always is a fair amount that comes off the surface at this point). Sorry, I didn’t take a picture at this point. You’ll have to take my word for the fact that it simply looked like a chalk-white violin, with the grain and purfling quite obsecured by the dry mineral ground.

Sealer

Then I seal the violin, all except the “handle” portion of the neck. There are many things people use for sealer: Some use special commercially available preparations (I have done that, too), and some use very thin varnish, or shellac. For now, my sealer is a combination of Pine sap (yes, that sticky gunk that flows out of a cut in a pine-tree) and turpentine. The turpentine penetrates the wood very readily, taking the pine pitch with it. I allow the turpentine to evaporate off, leaving the pitch in the wood. I am of the opinion that the pitch is an OK thing in the wood, and that it seals the wood against further penetration by varnish. That’s my theory, anyway. 🙂 The mineral ground turns completely transparent under the saturation of the turpentine and pine pitch, and remains that way after the turpentine evaporates. Here is a photo of the violin with the mineral ground rendered transparent by the sealer. It will probably take a few days to get absolutely dry, (turpentine evaporates slowly) so this is the last photo for this post:

Varnish

I have used a wide variety of varnishes, but currently I am using a spirit varnish concoction. If I need more color, I use the “Transtint” dyes available in woodworking stores and online. It does not take a great deal of dye…you want to go easy on this stuff. I have considered extracting dyes from plants, etc. Never have gotten around to it. 🙂

I’ll show the varnishing process in the next post.

Thanks for looking.

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