Tuesday, November 16, 2010

Weissenborn Style 1 Repair - Part 2

With the top under clamps, my focus switched to the new reproduction bridge. Of course the original was Maple, not Rosewood like the former replacement, and so we begin simply with the wood itself. West Virginian Sugar Maple, the finest of which are cut from Mandolin billets.

For restoration work like this where the new must fit the old footprint perfectly - I will make several and pick the best one:

The finish process begins with Gamboge - a resin used by old time violin makers, but also interpreted by other greats such as Lloyd Loar and Weissenborn, under the dye:

Black aniline:

The new bridge will be french polished and distressed to match the old, but more on this later.

Internally the guitar needed several back braces re-glued, and just the X brace patch on the top.
Here you can clearly see the partially loose back brace:

Sticky sandpaper and a feeler gauge preps the brace to be re-glued. You don't want to remove material here, so much as clean out the old dirt and junk:

Different repair situations require different kinds of techniques. For this brace I am using a simple but extremely effective stick jack against the X brace to glue it back in position:

Another brace re-glued. In this case the new glue reactivates the old glue squeeze out:

Where there was no squeeze out originally, you can clean away the excess and without a trace:

Next comes the plugging / rebuilding of the top for the new bridge. Following the previous "repair", there were three critical details in my eyes both from a structural standpoint, but also musically speaking.

1. Repair worn bridge pin hole ball end damage. This is what happens as a result of improperly slotted bridges, or slotted pins. And quite frequently its a combination of the two such as with this guitar.

2. Plug pin holes. The previous replacement bridge had incorrect bridge pin arrangement, which had almost doubled each hole in size, making it almost impossible for the string ball ends to seat properly.

3. Re-glue damage from the previous repairers bridge removal attempt.

These reverse tapered plugs covered issues 1 & 2 in one single operation step. Each plug is cut to fit each pin hole exactly, and glued into place:

Plugs glued and leveled. The damage from original removal was repaired through a partial re-glue of the top, and also filleting slithers of Koa and hide glue into the damaged areas.

The top and new reproduction bridge fitted, and ready to be glued:

The final part in our repair story tomorrow!

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