Trim Braces Before or After Gluing?

[Parker135]

After a successful first mandolin build last winter, I'm on numbers two and three of Gibson Army/Navy style flat top mandolins. These two are mostly all about trying different woods and experimenting some with construction details. I hope to try a carved arch top in the future.

The plans and photos I'm working from show the braces shaped on the ends before gluing. They're first contoured with a 10 ft radius to induce some arch when gluing. I built the first one this way, clamping on the thinned-down ends of the braces. I'm now wondering if it might be better to leave the braces at full height across the top and back to retain stiffness while gluing (hoping to induce a little more arch) and then trim later with a sharp chisel in the traditional way. Any downsides to this process, other than the possibility of messing up while trimming after gluing?

Thanks,
Parker

[Graham McDonald]

Should make no difference either way.

Cheers

[Tom Haywood]

The biggest down side I see is that if the chisel slips you risk gouging the very thin side and risk a side split later on. I keep the top of the brace flat so the clamping is even. I contour the ends of the brace on the sanding station before gluing, because it is quick and reliable for removing that chunk of wood. Then only a small amount of rounding the edges in the contour is required after gluing, along with "voicing" the plate while shaving the rest of the brace. The bottom of the brace is sanded to the desired arch shape before gluing.

[Parker135]

Hi Graham, and thanks for your reply. I'd almost given up on seeing a reply, thinking later it's probably a silly question. It's easier to at least rough-shape the ends of the braces before gluing, but I thought maybe there is some magical/traditional reason for leaving the braces flat across the top until after gluing. I've been watching too many guitar building videos perhaps.

Tom, so you keep the top of the braces flat before gluing (easier to clamp) but you do contour the ends first. Then you go back and contour the top edge and trim trim things up. That's what I did on my first build. I think that's the way I'll proceed. As far as voicing the flat top plates for an army/navy style, I wouldn't really know where to begin. That's probably several builds in the future for me. Hopefully I'll pick that up along the way. I'd love to try one of Graham's carved-top designs next.

Thanks guys.
Parker