Posts Tagged ‘glue’

Beginning Two New Violins

Please share with your friends!

Beginning Two New Violins

First Things First:

I began by making sure that I had appropriate wood for both instruments: I wanted a one-piece back for the Guarneri model instrument, with deep flames sloping downward from left to right, and I wanted a heavily flamed two-piece back for the Stradivari model…both of European Maple, with ribs to match them, and European spruce tops. I had them, all right, so I bookmatched the two spruce tops, and the back for the “Titian” Strad attempt, and left them to thoroughly dry. Afterward, I visited my son’s guitar shop and used his power planer to flatten the plates, and bring them each down to the thickness I wanted for the arching height.

Prepared plates: European Maple and Spruce

Prepared plates: European Maple and Spruce

 

Working Vacation

I took a week off from work, intending to “get a lot done” on the violins, but ended up sick for most of the week. Besides, Winter is coming on, and we needed to get firewood in, so Ann and I loaded and hauled and stacked firewood for a couple of days, and I got about two good days of work on the violins. During that time, I installed blocks in the molds, shaped them to receive the ribs, thinned and bent the ribs, and installed them. Last, I installed linings, to add stiffness to the edge of the rbs, and additional gluing surface. The ribs, like the back plates, are European Maple, but the blocks and linings are willow…not sure what variety. I like weeping willow the best, because it carves and bends so nicely, but other willows work well, too, sometimes.

Guarneri form with blocks and ribs.

Guarneri form with blocks and ribs.

 

Ribs shortened

Ribs shortened

 

Adding linings.

Adding linings.

 

Linings installed, glued, and clamped.

Linings installed, glued, and clamped.

 

Then, once I had the linings in place, I trimmed the rib corners to their final shapes, and flattened the front face of garlands, after which I used the garlands themselves to trace out the shape of the top plates. Finally, I cut out the top plates and shaped them to the exact outlines I wanted, and I was ready to begin arching. I will do the same thing for the back plates later.

All four plates, both garlands, with neck blocks.

All four plates, both garlands, with neck blocks. Strad model on the right, Guarneri on the left.

 

Slow Start

I didn’t get much of anything else done, this week, as I was at work, mostly, annnd, Thursday, some fellow failed to yield on a roundabout, and totalled my wife’s car, as she was coming home from the grocery store. The roads were very wet, which may have contributed to why he was unable to stop, and why the impact spun her car around, 180 degrees, and hurled it off the road, into a field, next to the roundabout.

Ironically, she had also just gone to DMV, and had paid $193 to renew the DEQ testing, and registration, as well as filling her gas tank, to the tune of $40. So all that was wasted, too, but she is completely unhurt, for which we are deeply grateful. Guess it is time for her to get a newer car. 🙂 There was also a dented can of beans, and two squashed bananas…but I ate the bananas, and tonight we ate the beans. No loss there. 🙂

This evening, however, I got home fairly early, and I got most of the arching done on the Stradivari-model top plate, so at least that feels better, in terms of productivity. I will try to complete it tomorrow and repeat the effort on the Guarneri top plate.

I will post more pictures later.

 

Thanks for looking

 

If you found this post helpful, please share with your friends!

More Progress on the “Plowden-model” Violin

Please share with your friends!

More Progress: The Plowden-model looks like a violin!

Removed the Mold and Installed the Back Linings

One nice thing about this (French-style) mold is that it is easy to remove– it usually takes less than five minutes to get it out, provided I have waxed the non-glued surfaces of the mold, so there is no chance of an accidental adhesion to the ribs. I simply use a flat chisel to crack the glue loose at each block, where it is attached to the mold, and then slip my parting knife (in reality, it is an old potato knife) between the block and the mold, to make sure nothing is still adhering to the mold. After that I can slide the mold out by lifting as shown, while wiggling each individual block to make sure they are all moving evenly. The only drawback is that I have to install the back linings after the mold is removed, and the rib garland is pretty fragile. In the past, I have used a two-part collapsible mold, in the italian style (centered between the front and back edges of the ribs); but it is more difficult to remove. The only real advantage is that I can install all the linings while the corpus is still on the mold, and still get the mold out without too much trouble. I believe it does have a slightly greater tendency to leave the ribs slightly convex in the center, as well, and some people find that attractive. (I do too…. Perhaps I will eventually go back to using the Italian-style molds.)

Back before mold removal

Back before mold removal. You can see how thin and fragile those ribs are.

 

This time, the linings went in without a struggle, though, and the whole task took about 30-40 minutes. A few hours later, the glue had dried, and I was able to remove all the tiny spring-clamps, and get going on leveling the back of the garland, and cleaning up the interior.

Back linings installed,

Back linings installed, ready for shaping and smoothing.

 

Blocks and linings before shaping and smoothing.

Blocks and linings before shaping and smoothing. I had trimmed the front side of the blocks, and the front linings, before I installed the front plate.

 

Blocks and linings shaped, ready for scraping and smoothing.

Blocks and linings shaped, ready for scraping and smoothing. The blocks and linings are weeping willow…the bass bar is Sitka spruce.

 

Cleaning up the Interior

Cleaning the interior primarily means shaping the linings and blocks, after the mold is out of the way, but it also is a final opportunity to scrape any rough spots, and make any minuscule repairs. So, I put on my magnifying visor, and look things over very carefully. I use a knife to trim the linings so that they are triangular in cross-section, thickest at the edge, to suport the edge of the rib, but tapered so as to not restrict the vibrations of the middle of the ribs too much.

One thing I have to remember, at this point, is that it is also my “last shot” at the interior of the back plate, so, before I install it, I carefully check and scrape it, and, as a final “seal of approval”, I install my signed and numbered label, gluing it in place where it will be visible through the bass-side sound-hole. All my instruments are individually hand-crafted, and each ends up a signed and numbered original, not a mass-produced instrument. I’m really not interested in doing things the “factory” way.

 

Installing the Back Plate

I used to complete all the work on the back plate, including purfling and final edge-work before installing it on the garland. But I have recently altered my order of operations so that I purfle and do edgework after the plate is installed. This allows me to adjust the plate overhang boundaries, and make final decisions as to how I want things to look, before permanently locking the shape in place by installing the purfling.

I also used to “self-induce panic,” by spreading hot hide glue around the perimeter of the garland and plate, and then frantically trying to align the edges perfectly and adjust all the (25-30) spool-clamps, etc. before the glue gelled. That was a fool’s-errand, as the glue usually gels far more quickly than I could ever get everything clamped in place. The late Sam Compton shared how he applied the glue and allowed it to gel, then aligned everything at a leisurely pace, gently clamping everything in place.  Afterward, he went around the perimeter with a hair-dryer, gradually warming the plates until the glue re-liquefied. Finally, he tightened the clamps just enough to completely close the joints. Pretty clever.

I ended up clamping everything dry, then loosening a few clamps at a time, and slipping the hot hide-glue into the seams, using a very thin palette knife. That seems to work pretty well, and definitely eliminates stress. (His method probably is even better, but this is how I do things, for now.)

Back plate glued in place, using hot hide glue and spool clamps.

Back plate glued in place, using hot hide glue and spool clamps.

 

Label visible through f-hole.

Label visible through f-hole. The f-holes still will require quite a bit of smoothing.

Final Edge Shape and Purfling

Once the back is securely glued in place, I can trim the edges to exactly the shape I want, so that the overhang is matching the front plate, etc., and then begin purfling.

Front view: back plate has been installed and trimmed to size.

Front view: back plate has been installed and trimmed to size.

 

Back plate installed. Side view, before purfling and edgework.

Side view, before purfling and edgework.

 

Back plate installed and trimmed to size, before purfling and edgework.

Back view: before purfling and edgework.

I use the purfling marker to scribe in the double lines (except for the corners) where the purfling will be inlaid. I then draw in the corners very carefully. I have occasionally used a template for the corners, but it seems to not always work, since the corners are not always exactly the same. So I end up just making some layout marks to get the limits delineated, and then I draw the corners in, freehand.

I incise the purfling slot with a small, sharp knife, in three or more steps:

  1. The first pass with the knife is very shallow and light, only serving to deepen all the scribe marks.
  2. The second and third passes bring the purfling slot to the correct depth, and
  3. The last step is to use a purfling pick to remove all the waste wood between the paired cuts.

 

Purfling slot partially completed;

One-piece European maple back: the Purfling slot is partially completed; but still too shallow, and a little too tight.

 

Purfling slot complet

Purfling slot is completed… it turned out to be a little too tight: I used a tiny sharp knife to trim the tight spots, until everything fit.

I check the depth and width of the slot by inserting a small section of purfling into the slot, all the way around, until I am sure that the slot is correct. then I bend and fit the purfling strips, and make sure the fit is as exact as I can make it, terminating in the classic “bee-stings” at the corners, rather than a simple “mitered corner.”

Finally, when all is as close to perfect as I can manage, I lift each section of purfling partially out of the slot, one at a time, and slip hot, thin, hide glue into the slot, using the thin palette knife again. I press the purfling all the way down to the bottom of the slot, and allow the glue to dry before beginning the final edgework.

Back purfling completed.

Back purfling completed. Channel still needs to be cut and edgework is still untouched.

 

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 using gouges first,then scrapers, and bringing the smooth curve up to match the scribed limit. Then I file the outer edge to round in from the center of the edge of the plate up to meet the scribed margin. I true up lines using scrapers, files, and abrasives, and then I am ready for final varnish preparations.

We’ll talk about all that in the next post, and post pictures. I need to get this one wrapped up. I’ll show close-ups of the edges and corners next time. there is still a long way to go, but it is looking more encouraging. 🙂

Thanks for looking.

If you found this post helpful, please share with your friends!