Brendan’s Mandolin Part II: Rosette
Above, you can see the two book-matched halves of Brendan’s Red Spruce soundboard being glued together. There are many fancy systems for this task but I prefer good old sash clamps- you can adjust the pressure to exactly where you want it to be.
Once the ‘board is glued, it’s flattened and taken down to around 4mm prior to inserting the rosette.
This is the first time that I‘ve used Red Spruce and I’m very impressed by its stiffness and glass-like tap-tone. The stiffness is especially important on this mandolin, as Brendan uses quite heavy strings and according to my calculations the extra down force exerted on the soundboard would be the equivalent to another 2.5kg pushing down on the bridge, compared to the load applied by the gauge of strings that I normally use.
Anyway- with the soundboard cleaned-up, it goes into my jig which allows me to route oval sound holes and channels for rosettes.
The turquoise is glued onto plywood, to support it and cut into 3.5mm strips. The diamond shapes are then cut off (easier said than done). Once the diamonds are cut they are then soaked in water, to dissolve the hide glue attaching the turquoise to the ply. As you can see I cut far too many; this allows me to select the best ones and also I suspect that Brendan may want a few of these in the fingerboard.
The epoxy takes 24 hours to set and after some very careful cleaning-up,.....
Now is that pretty or what?