Thursday, January 29, 2009

Pipa Restoration 7. How to Repair a Tuning Peg

  • The tuning peg had been snapped into two pieces, and rebuilding one from scratch was out of the question. The wood looked like ebony, but not as oily. First, I superglued both parts together. While a firm bond was made, I wouldn't expect it to survive the rigors of use.












  • I carefully drilled two 0.25" holes through the bonded seam. Here I have a piece of sandpaper to roughen the bore.












  • Switching to aliphatic resin wood glue the holes were doweled. I surprised myself by not breaking the superglue joint when pushing in the dowels.













  • Hard to see it here, but the peg is in place after sanding the dowels smooth. The connection is bombproof and the peg is as good as new. I didn't try to mask this repair because the friction peg is an area of high abrasion.

Thursday, November 13, 2008

Pipa Reconstruction 6. New Soundboard.

Now, the update. Cutting away the existing binding was the only way to go. Otherwise, patching the cracked remainder would not look right or be structurally sound. Here's a shot of the body after I planed the binding edges flush with the body. You can also see the replacement crossbeams I rebuilt from pawlonia.














The sticks have to be precisely level with the rim, since they will glued to the underside of the soundboard. I used a straightedge to check that. The new soundboard is in the background.













Here's the new soundboard lined up for attachment to the body. Now the binding has to be formed and attached.













Using a cardboard template I built from a trace of the original, I'm clamping thin long strips of mahogany to fit the form. I steam-bent them to the general shape, and in this photo they 're drying.













Another rim shot, close-up. That's it for now.


















Last few months I get TWO monster gigs playing guitar. First I joined the praise band in our church. Another great break happened when the Pennyloafers band of Sugarloaf took me in. In the praise band we play Christian standards, and hard-rockin' hymns. In the Loafers I get to fulfill my longtime dream of 'comping' Jazz standards. We play for charity. My compensation for these adventures = PIE (
Payment In Experience).

Here We Go!

More about the PIPA reconstruction coming very soon! (I've been on sabbatical.)

Wednesday, April 2, 2008

Pipa Reconstruction 5. Inside the Bowl

Inside the Pipa are 3 support posts, attached to the bowl. Above these are two crossbars (removed). The bowl is hand-carved. One can see the divots of the builder's tools.
I have to deal with that nasty crack at the tail section. The hardwood is too rigid to clamp the crack back together. Precise clamping of the curved bowl is not easy, either. A wooden patch seems to be the best option
Here's a strip of mahogany I glued to cover the crack. That should halt any further cracking. On the outside, the crack is visible. I'll back-fill this with epoxy.
The damage to the soundboard binding is unacceptable. When I removed the soundboard, a lot of the binding came with it, especially by the tail.
I'm thinking about removing the binding, cutting it flush with the soundboard shelf. The binding could be rebuilt with a new strip of mahogany along the perimeter. This would simplify fitting of the new soundboard and make for a clean appearance.
I'd better sleep on this idea!

Friday, March 28, 2008

Pipa Reconstruction 4. Rebuilding Fret Blocks

Today I will describe how I re-created the missing 1st and 6th frets.

First, the scale length had to be determined. I did this using Stewmac's online fret program. Using existing frets 2 through 5 and the nut as references, I calculated a scale length of 71.9 cm.

















This number falls within the range of Pipa scale lengths I've seen. Fortunately for me, this instrument uses a twelve-tone scale!














I hotglued squared mahogany blocs and the nut into place. The nut's in sad shape but will suffice for measurement purposes. From the fret spacing table, I marked the locations on blocks #1 and #6 where I want to inlay the bone.














After squaring the cuts, I used the fret saw to cut the channels to a depth of approximately 3/16"














The rest was finesse. Using the sanding drum, Dremel tool, and coarse papers, I coerced the bone pieces and fret channels to fit together snugly. I cut a slight radius (you can't see it) on the underside of the bones before the final superglueing. This helped to give the side-view appearance a nice clean look, with no visible gaps bewteen wood and bone.















Finally, the angles were cut. They will be feathered-down to the precise height needed to form a perfectly straight line along the apices of all six blocks. Here's he roughed-in #1 block.

Sunday, February 3, 2008

Pipa Reconstruction 3. Replacing the soundboard.


Nasty cracks at the base, extending through soundboard as well as backboard. No way to fix this without removing the soundboard.

3/4 inch paulownia stock, which I split using a pull saw.

Sunday, January 27, 2008

Pipa Reconstruction 2. Rebuilding the headstock joint.



The point of no return: Here I've begun removing material from neck using chisels. A secondary mortise is being fashioned, so I can introduce a maple block which will become the new tenon. The elastic provides radial pressure on the soft wood, thus discouraging cracking.



Dry-docking the neck and headstock, to illustrate the fit. The newly formed channel is ready to be fitted with the new wood.


Roughing-in the new block. I'll tweak this with the chisel until maximum surface contact is gained. Then it gets glued with dowel reinforcements.


The finished tenon. The final cut parallels the curve of the headstock, while the hole accomodates the tuning peg. Note the dowel reinforcement.

After the final glue-up-the pieces are joined tight and straight. The headstock now vibrates as one with the body (a coupled system). Two more reinforcing dowels will be added.