After experimenting on the side with designs, cutting shell, routing cavities, gluing and sanding (the entire work-flow), it's time to perform it on the actual project.
I cut the final pieces by hand. using the headband magnifier has been extremely useful. If it looks good under magnification, it will look perfect to the naked eye. I don't have adequate lighting at my workbench (dining table...) and so the little led lights on the headband really help my eyes. Since the design is symmetrical, I glued two abalone pieces back to back and cut them simultaneously. This ensures identical shapes and also reduces the work time.
The shell pieces were positioned on the headstock relative to guidelines that I drew wi
th a pencil. Before routing the cavities, I needed to scribe the outline of each piece. One method calls for painting the ebony with some tempra paint and then scribing. The idea is that you would see a clean black line through the paint. I had tried that method on the side but wasn't completely happy with it. The paint was a little thick and it was dragging as I scribed. Also, it was a little messy while routing and as a result, the cavity edge was hard to see crisply. I ended up using a different method. No paint. I glued the shell pieces temporarily on the headstock and scribed directly into the wood. See photo. Once I popped the shell pieces off,
I rubbed white chalk into the scribed lines. The lines stood out very well and were easy to see throughout the routing process.The cavities were routed using a Dremel tool, mounted into a StewMac precision router base. I ordered several cutting bits from R. L. Schmitt and I'm impressed with the quality and service. since the design has very tight corners (the diamond points), I had to use a 1/32" bit.
The pieces were dry fitted, adjusting the cavity until they pieces were almost flush with t
he surface. At that point everything was ready for gluing. This is a photo of the dry fitted pieces.For cement I used slow-curing epoxy, mixed with black dye. Since the headstock overlay is made of ebony, the black epoxy would fill the small gaps around the shell and make everything look flush and neat. I put a small amount of epoxy into each cavity and pressed the shell pieces in. The excess glue oozed out and settled all around and on top of the shell. It looked messy at that point. Unfortunately I don't have a photo of that stage. I let it cure overnight.
The Next day I sanded down the dry epoxy until I reached the shell and the wood. Everything was leveled . You can see a photo of the post-sanding stage. This is still not the final sanding for the project but it flattened the shells and the overlay.
One small problem I discovered was a small depression in the surface of one of the shell pieces. You could feel it if you ran your fingers over the shell. I'm not sure how it came about. There could have been a small void in the shell , which got exposed when I sanded down. The shell is made of thin layers or flakes and a piece could have lifted off at some point. At the advice of John Hamlett on mandolincafe.com, I was able to fix the shell by dropping a tiny amount of CA (superglue) onto the shell surface. It dried clear as glass and I was able to sand it down again to a flat surface.
That's it. The inlay is done and I'm very happy with the design and result as well.
Moving on to fitting the neck - the next chapter in this adventure
