Posts Tagged ‘back plate’

Closure!

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Closure!

Leveling the Garland

Last time I posted, I had installed the back linings, shaped the blocks and linings, and was nearly ready to close the box. It looked like this:

The blocks and linings are shaped.

The blocks and linings are shaped…but the garland is not leveled, yet.

 

To the unassisted eye, the back of the garland really looked pretty flat. In fact, I had used a hand-operated abrasive tool (a Sandvik tool…they apparently went out of production, years ago…but I love the few I have) to try to level it all the way around, thinking it might be easier. But when I clamped it up, to test the plan, it was not even close to level…so, back to the sanding board!

To level the garland, I made pencil marks all around the mating surface of the garland, and then rubbed the entire structure on the abrasive surface until all the marks disappeared. Presto! Flat!

 

Installing the Back Plate

Then, while the glue was heating up, I carefully went over the perimeter and inner surface of the back plate and made sure the curves were smooth and consistent. Once I was satisfied with it, I carefully aligned the back plate on the garland, pushing and pulling a little to get the overhang even, all the way around. I clamped only at the blocks, initially, then began using a thin-bladed palette knife to insert glue into the joint. I removed the clamps at the bottom block, first, and inserted glue so that the joint between the bottom block and the back plate was fully coated, then slid the blade left and right, as far as it would go, spreading glue on the joints between ribs/linings and back plate. I quickly reapplied the clamps at the bottom block, and added more between there and the corners. Loosened the next set of clamps, and repeated the routine.

Once the entire perimeter was glued and clamped, with an extra clamp at the button-to-heel joint, I could set the whole assembly aside to dry. It is closed!Ā  (I really like looking at that one-piece European maple back.) šŸ™‚

Closed corpus, back view.

Closed corpus, back view.

 

Closed corpus, side view.

Closed corpus, side view.

 

Closed Corpus, Front view.

Closed corpus, front view.

I will let the glue dry overnight, then remove the clamps and trim the heel to the correct profile, trimming button to match the heel, so that they are shaped as one unit. Then I will carve the slot in the back plate for purfling, install the purfling, and, finally, prepare the whole instrument for varnishing. I hope to be ready to begin the finishing process by this weekend.

 

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More Progress: Plates and Scroll.

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More Progress: Plates and Scroll.

Completing the Back Plate

I continued planing away wood from the inside of the back plate until it was very nearly correct, then switched to scrapers, and completed the inside surface, so that it looks to be a smooth continuum of curves, transitioning without a ripple. TheĀ  plate will require no further attention until I am ready to install it. Unlike the front plate, I intend to install the purfling later, after I am completely sure how the garland will respond to having the mold removed (sometimes they can move, and change shape a little.)

Back Plate Graduation complete.

Back Plate Graduation complete.

 

Scroll Progress

I also continued working on the scroll. My hands were getting pretty tired, so I took a break from that. It is still quite rough, but, here’s how it looked at break time:

scroll beginning

Long way to go.

 

scroll progress

On the right path, but “miles to go before I sleep.”

 

Bass Bar Fitting

To fit a bass bar, I begin with a completed front plate, and lay out the position of the bass bar, so that the distance from the center to the bar, level with upper and lower bouts at maximum width, is 1/7th the full distance from centerline to the edge at those respective points. Usually, that means that the lower point will be about 15mm from the centerline and the upper one about 12mm (as it is in this case.) I lay out a line through those two points, and observe where it is, nearest to the bass-side f-hole. If it is too close, I “fudge” it away, a bit, trying not to change the angle. (The bass bar has to clear the f-hole.) Then I mark the two ends, 40mm away from the ends of the plate, and that is the place to fit the bass bar: the “footprint”, so to speak.

Bass bar position laid out.

Bass bar position laid out.

 

I use chalk to fit my bass-bars. I have never had a good enough eye, and a sure enough knife-hand to accurately fit a bass-bar without the use of chalk, though I have known master makers who regularly did so…perfectly. (Sorry… I’m not good enough for that.) On the other hand, I have had some nasty experiences with the residue of blue chalk mingling with the yellowish hide glue when installing a bass bar: it left a very ugly green stain…and it never completely came out. So…what to do? In the first place, I switched to pink chalk. If a little chalk is left, the glue will simply make it look a bit orange. (No problem.) But, I really don’t want chalk residue at all.

A friend showed me the paper “gauze” tape available in pharmacies. It is thin enough to completely conform to the surface of the plate, andĀ  produce a good fit, and, it is slightly translucent, so I can see my layout lines through the tape, and keep the chalk on just the path of the bass bar. I first use a compass to mark the general shape of the bottom of the bass bar, and then trim it with a knife and a small plane. That gets me “in the ball-park,” so to speak. After that, it is chalk-fitting time.

The front plate is made of European spruce, but I chose Sitka spruce for the bass bar. There is quite a contrast in color between relatively fresh European spruce, and well-aged Sitka spruce. It actually made it a little difficult to see the pink chalk against the dark wood. But it worked.

Bass bar blank, knife-trimmed after tracing the shape with a compass.

Bass bar blank, knife-trimmed after tracing the shape with a compass.

 

paper gauze tape

This is the paper gauze tape I use for chalk-fitting.

 

Paper gauze tape and pink chalk

Paper gauze tape and pink chalk, ready to begin chalk-fitting.

 

Layout lines visible through the tape.

Layout lines visible through the tape.

 

Layout lines traced over on the tape, to make them more visible.

Layout lines traced over on the tape, in pencil, to make them even more visible.

 

Chalk on tape.

Chalk on tape.

 

Chalk transferred to bass bar

Chalk transferred to bass bar

 

The idea, in any chalk-fitting procedure, is to press the fitted part (being fitted) into the chalked surface to which it is being fit, then trim away only the portions where the chalk transferred. So, in the case of the bass bar, I need to press it into the chalked top plate, and then check the bottom of the bass bar blank, to see where to cut. I trim off the obvious spots, and try again. Ideally, every time I try, I will get a broader transfer of chalk. When the whole area gets a light dusting of chalk at one time, the fit is as close to perfect as I can get it. I remove the tape, wipe off any chalk residue, slather the hot hide glue onto the bottom of the bass bar, and clamp it home. On a good day, it takes me a half-hour. On a bad day? Don’t ask… šŸ™‚Ā  This time wasn’t bad, though.

Chalk-fitting complete; Dry-clamped to check fit.

Chalk-fitting complete; Dry-clamped to check the fit.

 

Tight fit

The fit is good!

 

Glued and clamped

Glued and clamped. 

More Scroll Progress

While the glue was drying on the bass bar, I went back to work on the scroll. It was looking verrry rough when I had to take a break, so it is nice to see it progressing better, now. There is still a lot to do. I have to excavate the pegbox, and cut the fluting in the volute. But this is as far as I am going tonight. I am glad to call it a night, and let my hands rest.

More scroll progress

More scroll progress: there is still a long way to go, but it is looking better.

 

Scroll partly complete.

Final status for tonight. Looking a lot better, and more encouraging to see.

 

I have other things to do tomorrow, so I may or may not get to work on the violin. At the very least, I expect I will be able to trim the bass bar to the shape I want it, but beyond that, I don’t know.

 

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3/4-Size Violin Completion

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Completed the 3/4-Size Violin!

I had a number of other projects going, so I neglected to maintain the website presence…the only post lately has been of another violin resurrection. But…I hope to change that.

The last post was of the neck-set on the 3/4 violin. It looked like this– but the back plate was not made, yet. Most makers complete the entire corpus, then set the neck. I complete the rib garland and the front plate, then set the neck while the inside mold is still in place. This allows me to get the neck-set perfect, and to level the back of the garland,Ā including the back of the neck-heel, before making the plate. When I install the plate, it fits perfectly, only requiring the final trimming of the heel and button together, to establish the optimum height in the center of the curve of the heel.

Neck-set side view

Neck-set side view

Completing the Back Plate

So, the next thing was to trace the back plate, and complete it:

Corpus with back plate blank

Corpus with back plate blank

 

Beginning to carve the back archings

Beginning to carve the back archings. There is a long way to go!

 

Once the arching is complete, I cut the purfling slot

Once the arching is complete, I cut the purfling slot

 

 install the purfling, dry

Then I install the purfling, dry, to make sure everything fits correctly. That strip of aluminum is my bending strap.

Then I glue the purfling in place.

Then I glue the purfling in place.

 

Edge Crest marked

Then I mark the edge of the crest, so I know where to carve the channel.

 

channel complete

Then I carve the channel, using a gouge, and use planes and scrapers to fair-in the curves of the channel and the archings.

 

Arching and purfling complete

Here, the arching and purfling are complete…but the graduations (inside arching) are not begun.

 

Graduation

I begin by measuring the thicknesses all over the plate, so as not to run into any surprises and make the plate too thin. Then I use gouges and planes to bring all the thickness close to what I want. But, to make sure I don’t go too far, I measure and carve out small spots all over, to the exact thickness I want in each little “polka-dot”. That makes a “graduation map” that allows me to follow my plan to completion, by removing all the excess wood between the dots, thus “connecting the dots.”

There are other ways to do this. One involves a special tool, commonly called a “Strad-Spike”, because one was found among the tools of Antonio Stradivari. I have seen them and and have actually used them, but have never gotten around to building one. So…

 

graduation map laid out

Graduation map laid out.

 

Final thicknessing in progress.

Final thicknessing in progress.

 

Graduations almost completed.

Graduations almost completed.

By the way, I think it is interesting to hold the plates up to a lamp and see how much light comes through:

translucent spruce

That is a lot of light coming through that spruce plate…it is about the thinnest plate I have made.

 

translucent maple

Even the maple lets a little light through.

Closing the Corpus

Finally, to install the label and close the corpus. (I always forget to take a picture of the label…sorry.) Most makers put their label in after everything is fully completed. I usedĀ to do that, but I found it so frustrating to get a glue-coated label through the f-hole, line it up correctly and get it smoothed out on the back plate…all working through the f-hole…that IĀ decided my labels will go in when I close the corpus; always. That means the label predates the completion by a few weeks at most, as a rule. I think one time there was a long wait, Ā but that was the lone exception.

Closing the corpus

Closing the corpus

 

Fully glued and clamped, using hot hide glue and spool-clamps.

Fully glued and clamped, using hot hide glue and spool-clamps.

 

Closed corpus from the back.

Closed corpus from the back.

 

Closed corpus from the front.

Closed corpus from the front. Dainty little thing, isn’t it? This is my first 3/4-size violin, and it feels pretty tiny.

 

Finishing

I removed the fingerboard so as to be able to easily access the entire exterior, for final scraping and finishing.

After that, I had a lot of “scraping and looking” to do. (Scrape and look, using a low-angle, dim light, then scrape and look some more.) When everything was as smooth as I could make it, and exactly the shape I wanted, I stained the entire violin with coffee, to get rid of the stark-white bare, new-wood look. It takes at least three coats, usually, to get the color dark enough that it will not shine through the varnish. The collateral effect is that the grain raises because of the water. So, I sand it lightly, to smooth the grain “just enough.” I want the grain to be visible in the final state, but notĀ too visible.

Coffee stain

Coffee stain

 

Then, I rubbed in a coat of the mineral ground. I brush it on liberally, rub it in hard, with my fingers, then wipe it off as hard as I can, using a rag. When it dries, the instrument will be whiter than ever– chalk-white, all over. The first time I did this I was pretty alarmed at the look, but I had just watched Roger Hargrave do the same thing, and knew that the white mineral would completely disappear with the first coat of sealer or varnish. And it did!

Here is the violin with the sealer applied:

sealer front view

With three coats of coffee, and the dark sealer, the wood looks pretty dark. But it will look good under the varnish.

 

The back, with the seal-coat.

The back, with the seal-coat.

 

After that it was a case of applying several coats of golden varnish, then a few coats of red-brown varnish, and a final two coats of the golden stuff.

 

Front varnish nearly complete

Front varnish nearly complete

 

Back varnish nearly complete

Back varnish nearly complete.

 

front with the final coat of varnish.

There is the front with the final coat of varnish.

 

Set-up

Standard set-up, and the violin will beĀ done! That includes the saddle and endpin, as well as re-installing the fingerboard, fitting and installing pegs, a bridge, the nut, the soundpost, tailpiece, and strings. A chinrest completes the instrument.

Bottom of the violin before the endpin

Bottom of the violin before the endpin and saddle were installed.

 

Endpin installed

Endpin installed: saddle is next.

 

Heres the plan: a rounded saddle

Heres the plan: a rounded saddle to prevent “saddle cracks”. They work because there is no sharp corner to act s a stress riser.

 

 footprint of the saddle

There’s the footprint of the saddle: no further shaping is done until I cut out the mortise in the front plate.

 

Traced saddle mortise

I traced the footprint onto the front plate, and began cutting out the mortise.

 

cut out saddle mortise

Then I cut out the mortise using sharp gouges and a small knife. Any nicks in the varnish will be retouched later.

 

The varying thicknesses of the top plate can then be traced onto the saddle itself, and final shaping can begin.

 

Saddle and endpin complete

Saddle and endpin are nearly complete. The saddle will be filed a little more, and the varnish retouch will happen later on.

 

fingerboard and pegs installed.

I reinstalled the fingerboard, and while the glue is drying, I fit and installed the tuning pegs.

 

Fingerboard and pegs complete.

Fingerboard and pegs complete. Notice the nut is also intalled.

 

Completion

Finally the little violin is complete!

 

Front view of completed 3/4-size violin

Front view of completed 3/4-size violin

 

Side view...

Side view…

 

And the back view.

And the back view.

 

finished scroll

Close-up of the scroll

Thanks for looking. Please keep in mind that the Marylhurst Musical Instrument Show will be April 29th and 3oth. If you can make it, I hope to see you there. This little violin will be there for you to test drive, along with others.

 

 

 

 

 

 

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