Archive for January, 2019

Closure and Final Scraping

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Closure and Final Scraping

Graduation complete

When I last posted, I was beginning the graduation process for the back plate of the Titian copy. I had a pretty busy week, but this is where it went:

Completing the graduation of the Back plate on the Titian Strad copy.

Completing the graduation of the Back plate on the Titian Strad copy.

 

Once the graduation was complete, I removed the interior form (sometimes called the “mold”) from the garland, and trimmed the blocks and linings, so that the garland and back plate could be joined. I had already flattened the back of the garland, so this was a pretty simple step.

 

Graduation complete: ready to close!

Graduation complete: ready to close!

I aligned the plate on the garland as closely as I could, drythen began applying clamps to hold it. I adjusted the position slightly as I progressed, so that when I finally had clamps on all corners, and in the center of each bout, the position was exactly what I wanted. Then I began removing two or three clamps at a time, and slipping hot hide glue between the plate and the garland, using a thin palette knife. I quickly replaced the few clamps I had removed, and more clamps between them, so that the section was securely attached. Then I moved to the next section and repeated the process, until there was glue and clamps all the way around. I saved the neck block for last, because I intended to add that larger clamp, and it would have been cumbersome, had I used it early in the procedure.

 

Closed, clamped, and resting overnight.

Closed, clamped, and resting overnight.

I allowed the glue to dry overnight, and, in the morning, I removed the clamps and began carving the heel, and working on the edges of the back.

Closed, but a long way from done.

Closed, but a long way from done.

 

Shaping and scraping the heel.

Shaping and scraping the heel.

Finally, all the surfaces looked right, and the next step will be to remove the fingerboard, and prep the entire corpus for the varnighing process. The Guarneri copy is side-lined for the moment, which is what usually happens when I attempt to make more than one instrument at the same time. I usually get to a certain point on all of them, and then run with one to the finish, and come back for the rest. (Ah, well…at least they do get done.)

Ready for varnish prep. Front view.

Ready for varnish prep. Front view.

 

Ready for varnish prep. Back view.

Ready for varnish prep. Back view.

 

Full Front view: ready for varnish prep.

Full Front view: ready for varnish prep.

 

Full Back view: ready for varnish prep.

Full Back view: ready for varnish prep.

 

Next time, I will either talk about the varnishing preparation process, or I will follow the work on the Guarneri. Probably the varnish-prep. 🙂

 

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Purfling and graduating the back plate

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Purfling and Graduating the Back Plate

Purfling came first, this time.

I decided that I would prefer to purfle first, then graduate, on this plate. Maple is much tougher than spruce, and I wanted maximum mobility as I cut the purfling slot, as well as avoiding any danger to the rest of the indtrument when forcing the purfling into the glue-filled slot. It can require a great deal of pressure.

 

I used the purfling marker to trace out the location of the purfling slot.

I used the purfling marker to trace out the location of the purfling slot.

 

Then I began incising the sides of the slot, and removing the waste wood.

Then I began incising the sides of the slot, and removing the waste wood, with a purfling pick.

I always forget, between instruments, just how tough the European maple is. I always find that I have to take breaks once in a while, and allow my hands to rest.

 

Back purfling slot.

I always find the back purfling to be physically difficult, but it is easier to do clean work.

 

Back purfling slot complete.

Back purfling slot complete.

 

After cutting the slot and removing the waste wood, I double-check the width ans depth of the slot by inserting a scrap of purfling into the slot, and dragging it around the entire slot, so that I know the purfling will fit cleanly.

Then I use a bending iron to bend the purfling, I cut the miters for the “Bee-stings”, and I insert the purfling, dry, to get a perfect fit.

 

Purfling installed dry.

Purfling installed dry.

 

Before I start gluing, I also take time to mark the edge of what will be the “crest” of the edgework, so that I don’t gouge too deeply or too wide, when cutting the channel. After gluing, it is difficult to get the pencil to mark on the wood, if it is either damp or glue-coated.

pencilled-in crest marks.

If you look closely, you can see the pencilled-in crest marks.

 

Finally, I lift out each purfling segment, one at a time, and slip hot hide glue under the purfling, then quickly press the purfling back down into the slot. I use a hard plastic roller to help force the purfling deeply into the slot.

 

The purfling is glued in place

The purfling is glued in place, and I can cut the channel now.

In this case, I chose to work on the graduation, next. I did not get it done, but I am within an hour of completion. Then I can conplete the plate, add the label, remove the mold, and close the corpus.

 

 

Graduation in progress.

Graduation in progress.

I will also complete the channel and the inner edgework, before removing the mold and installing the plate. But it is getting there…

Vacation is a hard time to get things done, because the people take higher priority, and everything eats up the time. (Ah, well…always good to spend time with family.)

 

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Purfling and Neck-set

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Purfling and Neck-set

Purfling the Front plate

It is a lot easier to purfle the front plate before the neck is installed. But I have found that I can get better results purfling after installing the plates, than before, though I was taught to purfle the plates very early, before even completing the arching. But what consistently resulted was that I could not reliably produce even-looking edge-overhangs when I purfled before plate installation.

So…beginning purfling, here:

I have scribed the lines, and am beginning to incise them.

I have scribed in the lines, using a purfling-marker, and am beginning to incise them.

 

Removing the waste wood fromn the slot.

Removing the waste wood from the slot, using a “purfling pick.”

 

Slot beginning to develop.

The slot is beginning to develop. I use the piece of purfling to check the fit of the slot.

 

Purfling slot is complete: ready for purfling.

The purfling slot is complete: ready for purfling. A knife, two purfling picks and the purfling marker are in view.

 

Purfling installed, but not trimmed: channel is next.

The purfling is installed, but not trimmed: the channel is next. I used the roller to press the purfling deep into the slot.

 

Neck Setting

I did not take as many photos as would have been ideal. I was concentrating on the work, and not thinking about pictures. Sorry.

The heel-end of the neck had to be as close to exactly the final shape as possible before I laid out the neck mortise. As it turned out, I had set the taper incorrectly, forgetting that I had deliberately left the heel long, so I had to re-shape the neck-heel. Fortunately, I caught it early, and was able to make the correction.

 

Neck ready to install.

 

When setting the neck, I make no further changes to the neck-heel, but rather, I carefully shape the mortise to receive the neck-heel.

Five factors have to come together for a good neck-set:

  • The angle of the fingerboard to the front,
  • The height of the fingerboard above the front plate edge,
  • The transverse angle of the neck,
  • The transverse “roll angle”, and
  • The distance from the upper end of the fingerboard to the upper edge of the front plate. (130 mm)

All five really must be perfect. Sometimes I can get it quite quickly. This was NOT one of those times. (sigh…)

But the end result was quite satisfactory: all five were correct, and the fit was tight. I slathered in the hot hide-glue, and rammed the neck home one last time: no clamps were needed.

 

Neck Set Complete.

Neck Set Complete.

 

Next, I will check the back-plate fit, complete the back-plate graduations, install the label, remove the mold, clean up the interior, and install the back plate. This is the “Titian” Stradivari model. I decided to include a scroll-graft and an ebony “button crown” on the “Plowden” Guarneri del Gesu model. So there will definitely be some additional steps to completion, there. I will try to remember to take more pictures.

 

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