. . .or relaxing over the Independence Day holiday, Shin continued working on the Banjo Killer. The rim, having been thoroughly cleaned and all its glue removed, was ready for the side braces to be reglued.
We decided to use Titebond for most reassembly operations because Titebond is a better gap filling glue than hide glue. Distortions, spatulas and whatnot have created a few minor gaps, so rather than remove a lot of wood in the process of refitting, we removed as little as possible and let Titebond do the rest of the work. Also, Titebond was the glue we used in 1995, so it ought to be Kosher.
The back was reglued using the ingenious jig devised by Cary Clements and described in detail in an earlier post. Lo and behold, it worked! We quickly routed a 5/8" channel over the original back inlay and glued an "insurance" splint.
After leveling the splint with a scraper and sanding block, a standard 3/4" back reinforcement strip was glued in place, entirely covering it.
We decided to go with new wood here because the several pieces of the original reinforcement strip were in tough shape and might not mate very cleanly with the back braces.
The back braces were finally glued in place using the go-bar deck and spring loaded go-bars. We cut up a sheet of rubber to protect the braces from the go bars.
The results were impressive. The tap tones were promising, considering that finish is already on the back, and should improve as glue cures. This back is ready to glue to the rim.
Before reassembling the top we decided to check thickness. Thickness with finish averaged around .118" or so, and that's pretty thin. Of course we don't know how age and flood damaged may have effected original dimensions. Before applying touch up finish we will use our infrared film thickness gauge to check original finish thickness, which we can subtract from total thickness and get actual wood dimensions.
The top of this guitar came from a very hard, heavy Alaskan sitka log that was salvaged from a salmon trap and probably submerged for decades. It's not surprising that it ended up so thin, as my style of building is all about varying top and brace dimensions to achieve a desired range of plate flexibility. Most Adirondack tops end up around .123" +/-, and sitka usually ends up thicker. A few thousandths of an inch doesn't sound like much, but stiffness increases exponentially with thickness, so a few pieces of paper actually make a difference.
We were never able to figure out how to close a gap in the center seam of the top above the soundhole, so we decided to splint it with a dark colored piece of sprue. A small patch was inlaid behind most of the patch for reinforcement.
Tomorrow we hope to finish regluing all of the top braces.