ll Work Page 1 ll Work Page 2 ll Work Page 3 ll Work Page 4 ll Work Page 5 ll Work Page 6 ll Work Page 7 ll Schematic ll ll Work List & Progress ll Site Map ll |
ll Work Page 1 ll Work Page 2 ll Work Page 3 ll Work Page 4 ll Work Page 5 ll Work Page 6 ll Work Page 7 ll Schematic ll ll Work List & Progress ll Site Map ll |
1966 Harmony Special Addition Silhouette Silvertone model 1488. ~ Inspections, work, Info and Progress Pages ~ ~ Truss Rod Cover Repair ~ |
ll Work Page 1 ll Work Page 2 ll Work Page 3 ll Work Page 4 ll Work Page 5 ll Work Page 6 ll Work Page 7 ll Schematic ll ll Work List & Progress ll Site Map ll |
ll Work Page 1 ll Work Page 2 ll Work Page 3 ll Work Page 4 ll Work Page 5 ll Work Page 6 ll Work Page 7 ll Schematic ll ll Work List & Progress ll Site Map ll |
The tip of the trussrod cover was broken on this guitar, as the "arrow head" covers on most Harmony Bobkats / Silhouettes were; It only took a small amount of over-tightening in a screw tightening session ....or plastic contraction with age, to make the tip crack and snap off. No problem, remove a good one from a donor while the one from this guitar was being repaird to replace upon the donor. NOT !..... All the donors covers were cracked and snapped too ! Nothing to do but to repair the one for this guitar, and the only identical one from a donor at the same time. Break out the super glue, white epoxy and proper tools. PROCESS: The cracks are 'V' beveled to accept glue and filler better. The cracked pieces are then tacked into place with super glue and accelerator. When the epoxy sets to just the right working consistancy, a thick bedding of white epoxy is applied to the back of the tip-half of the trussrod cover and sat on a sheet of wax paper (mold release) taped to the back of a masonite clipboard to ensure a flat working surface, ...and light pressure applied to the covers so the epoxy will work itself evenly onto the bottom of the covers. Extra epoxy is allowed to drain off of the applicator stick (half of a spring clothespin) in a string which is applied like a 'dairy queen' curl to the tip holes and the the areas where chipped pieces were missing, ....ensuring enough epoxy is applied to lay settle down and leave a crown to sand down rather than a convex cup that would have to be refilled. Below is one piece sitting on it's epoxy bedding and it's missing pieces filled, ....while the other piece is shown with it's tip super-glued on waiting for it's epoxy bedding and tip-hole fill of white epoxy. |
Here both pieces are bedded, filled and their slight weights applied: |
The epoxy is cured overnight and the filing and sanding to form the pieces can begin. Pieces of masking tape are applied adjacent to the surface to be sanded so that the clean / smoothe surfaces won't get any errant scratches. The sanding dust is carefully saved on the upside-down tuna can, and is used to fill the beveled cracks which will instantly soak super glue into the dust making a perfect and strong filler. The small screwdriver is used to lift and placethe dust while the round toothpick is used to tease the dust into place and tamp it if neccessary so that the crack bevels get a good load of dust. |
A closer look shows the sanding done on the piece on the left, while the rough form sanding is still in progress on the piece on the right. These are very delicate pieces and will snap if too much pressure is applied on any axis. Liight pressure and patience is required, especially when working around the tip that was originally broken due to it's delicacy. Just like wood, a medium heavy grit starts the sanding and is ended with #800 emory paper. Masking tape is applied and trimmed exactly to the bottom edges to tell me when the sanding reaches the original bottom edges. The pieces will later be finished with rubbing compound then polishing compound: |
The piece on the left had been sanded into form. The piece on the right is now ready for fine grit sandpaper to finish out it's form: |
The pieces are now ready for their holes to be redrilled. |
The pieces are entirely too delicate to drill with any kind of machine drill. So a hande of masking tape is made to hand spin the small drill bit back and forth lightly between thumb and first finger. A small precicion diamond rat-tail file is used to finish the holes out. A halfway done hole is shown below along with the drill bit tool. |
Masking tape has been applied to the back of the pieces and finely trimmed and and their edges sanded even with the trussrods edges. A coat of Tight Bond glue is then applied to the tape to basicly thicken the trussrods piece without permanantly altering it's original configuration. This will thicken the matrix of the entire piece and make the trussrod covers stronger for their future, and stronger during the compounding and polishing of the tops. The tape / glue reinforcement can be easily removed should anyone desire the trussrod cover to be a more original configuration in the future. |
Here the pieces are ready for trimming the thin glue tags and polishing. If I get the time I will etch the discoloration in the old cracks of the trussrod cover on the right and fill the etching with white plastic paint (the paint is a plastic), and polish it down level with the work. |
Were the glue simply allowed to soak into the masking tape's paper, the paper would wrinkle into an uneven surface; So when the glue tacks, the pieces are placed glue-down onto wax paper (as a releasing wax) on a smooth and flat surface (one of my masonite clipboards in this case) so that when the glue dries it will be flat and smooth. Wood shims bridge the 2 trussrod pieces and a weight applied to the shims whick will push the pieces down flat against the hydraulic resistance of the glue. |
Here we can see the effect that will give the back sides of the trussrods a flat smooth surface. When the pieces are removed from this "mold pressing" they will be ready for any fine sanding and polishing of any glue that might run out from the bottom and leave a thin run-over tag. |
Repaired truss cover installed. |
