Flattening the upper bout of an arched top...

I remember Chuck Moore saying that to flatten the upper bout of his tops (which he puts an arch to rather than a dome) he simply made a few passes on a flat surface with sandpaper mounted to the surface. This before gluing the top on. Easy enough, but I'm curious about the upper bout brace. Is it flat, or is it still sanded to have the arch shape?

I have yet to build a uke (no time, one day) but have built a few guitars. I arc my upper brace but then sand a flat spot in the middle of it to accommodate the fretboard.

When I did it, I kept the upper brace flat, the intent being to keep a flat area for the fingerboard to land on. I transitioned from flat to radiused in the middle of the waist. As best I could figure, that was how Chuck explained he does it. It worked for me, but it's entirely possible I misunderstood.

Nelson

The norm (at least on guitars) is a flat upper brace, slightly arched lower brace. For a Uke I wouldn't bother doming or arching the soundboard.

Now I'm wondering how to glue it up. Seems I can't just put the top face down in the dish and press the braces on with the fiberglass rods like I do for the back because the top brace will be flat and not fit the dish... I suppose I could do the lower bout in the dish and the upper out of it. Yup, that's what I'll do. Thanks for listening to me figure stuff out.

Or...... You can modify your dish by feathering in a flat area with bondo or other filler. This would create a dish with a radiused lower bout and a upper bout that is not totally flat but has a flat area to accommodate the fret board extension.

I've been bracing a 15' radius into my tops, then pressing them flat when I glue them on. The edge of the ribs is sanded flat to receive them. A quick swipe with a sanding board makes a level spot for the fingerboard to sit on. I've helped make thousands of Huss & Dalton guitars this way, though with a 25' radius to the top. A 25' radius on a uke top is barely distinguishable from a flattop, thus the 15' radius. We've made just as many guitars that maintained the radius, but I think the prestressed flat top gives an instrument more kick and volume. It also greatly simplifies the building process.