Tuesday, July 26, 2011

Harmony H1203 Sovereign - Beginning the Rebuild

It was June, and the heat in my shed was already starting to be unbearable in the daytime hours.  But, after months of research, deconstruction and prep work, it was finally time to start the rebuild!

Back in the early 1980's, when I built that classical Torres-style guitar, we did not have the Internet.  What I had to go by were some pictures and drawings I found in the SUNY-Binghamton library, and the advice of Associate Professor John Thompson.  I took two studio art courses with John before approaching him to be my advisor for this independent study.  In addition to teaching art, John played and made violins and other musical instruments, and was interested at the time in making a line of musical instrument kits.  Besides earning a grade for me, we figured the build would provide an opportunity for John to make some decisions on how to split up the kit build into what would be done in manufacturing and what would be left to the builder.

1984 Torres-style guitar.  Rosewood back, sides, neck.  Sitka Spruce top.

How we attached the front and back panels to the sides of that classical guitar is something I have forgotten over the years.  Considering that John built violins, my guess is that we used lots of spool clamps.  After building some spool clamps for the Sovereign, I did a dry fit.  To be sure I had enough to go all the way around the edge, and to be sure to clamp up the full surfaces of the neck and end blocks, I used a pair of quick clamps at each block.

Next, I removed the clamps, and put on some tape to protect the sides and front binding during full force clamping.

I found out pretty quickly how much things slide around with wet glue, so I used another pair of quick clamps at her waist to help hold things steady while putting on the spool clamps.

With the rest of the spool clamps in place, I replaced the bar clamps at her waist with spool clamps.  After cleaning up the excess glue from the edge, I left her alone to let the glue dry.

The next evening, I was very disappointed to find that my spool clamping did nothing to counter the sliding effect in a few spots.  In the picture below, you can see how the back panel is shy of the side at one of the bouts.  The slippage in the joint varied as much as 1/8", too much to be properly concealed with binding. 

After researching and designing a better clamping method, I removed the back for the second time.  Getting the back off without letting the heat of my iron detach the braces from the back panel was a bit more challenging.  All went well, and the only collateral damage she suffered was a bit of lining near the neck block. I made a replacement from some scrap spruce, glued it on, and shaped and sanded it while preparing the back panel and the rest of the linings for glue.  With some additional compression clamps made from wood scraps and threaded rod, I tweaked the shape of the body and put the glue on for the second time.

With the glue dried and clamps off, I was pleased to see a slight overhang of the back panel over the sides.

Unfortunately, a few inches at the two lower bouts got pushed out, leaving me with what was there last time:

Disappointed, I considered my options. First, I could try to conceal the joint with a second strip of binding.  That wasn't very appealing, considering I wasn't even sure how well I could apply one layer of binding, and the majority of the joint did not require this treatment.  Determined to get it right, I decided to try a technique known as slipping the heel. In researching this technique, I found it is sometimes performed at the neck joint of classical guitars, or on steel string guitars instead of performing the more invasive neck reset, to reduce high action.  In effect, the block is pushed inward at the back panel, the overhanging panel is trimmed, and cosmetic repairs are made to the finish to hide the repairs.  Similarly, I detached the back panel at the two lower bouts and the end block, just enough to be able to tweak the sides to that the back panel would overhang the sides as they already were at the rest of the panel.

I applied the glue and set a few more strategically placed compression clamps, a half dozen quick clamps and a strap clamp.

Even while clamping it up, I could tell there would still be two spots at the lower bouts where the binding would reveal some misalignment.  After the glue dried, I removed the clamps and thought about taking a small break from this part of the rebuild to regroup my thoughts.   The heat of the July summer in North Carolina helped convince me this was the best thing to do.

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