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So far I have thicknessed and joined the back and soundboard. Today I began to cut my braces (spruce) for the back and was on a roll and having a great time then I realized something....the grain orientation was not perpendicular to the surface it was to be glued onto. The grain was parallel and according to the books I have been studying they all say it should be perpendicular for better stability in changing humidity conditions. So I'm pretty sure you all will say the same, but I thought I would ask anyway. Should I go ahead and order some new billets of spruce and just start over?

2) My second question is when shaping the braces to fit the radius dish does the fit need to be perfectly tight like when we join the two soundboard halves together? I'm more concerned about this on the top than back. It looks like a good fit when placed on the radius dish, but when I place the brace on to the top of the template I have that matches the radius dish and hold it up to the light you can definitely see some gaps of light. I know it will be forced down in the gobar dish, but my concern is stability in the long term if it is glued with minor gaps

You need to reglue that brace. Over time the glue joint will fail. As for grain orientation I have seem older martins with braces that were not quartered , so I don't think that is going to be a big issue . It seems your gluing technique suffered . You can get the brace off easy enough. A fast rap with a hammer can pop them off pretty cleanly.
If you are afraid to do that use heat , or hot water and cotton thread , you can floss it off. What are you using for gobar rods? You should be using something that gives about 8 to 10 lbs of force. Use at least 4 or 5 of them. Dry fit your brace and you want to see a good mate of the joint.

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John Hall
blues creek guitars
Authorized CF Martin Repair
Co President of ASIA
You Don't know what you don't know until you know it

I haven't glued the braces yet thankfully. I am just getting them prepared so that when the humidity finally drops around here I can glue them up.

Jonathan, do you have sandpaper on your gobar deck? You will need some for sanding the rims to the contour of the top and back, but also you want to rough shape your braces to the radius of the dish and then simply sand them using the dish and you will have precisely the curve you need. When you are using the dish as a gobar deck you simply put news or craft paper between the sandpaper and the top or back plate. You are pressing the top and back plates into form with the dish, this is pre-stressing these parts which is what is desired. I hope this makes sense. I am sure there is probably something on this in the tutorial section of the forum. You can get sandpaper from either John Hall (Blues Creek) or myself. There are others around also I am sure.

Good luck

Shane

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Canada

Thanks Shane,

I did use sandpaper in the gobar dish to bring the braces down to match the radius. I ordered my radius dish from Kenneth Michaels guitars and it came with a matching template to trace the radius onto the brace blanks. I should have framed my question a little better in the beginning. After I sand the brace in the dish it fits nicely into the contour of the dish, but when I place it in the matching template and hold it up to the light I can see the tiniest sliver of light in certain areas where more was sanded away. I was just wondering if this was to be of any concern that should be remedied before the gluing process. If it looks ok in the dish then I imagine this is what really matters since that is the form it will be glued into. Even though both the dish and matching template were CNC machined maybe there is a tiny difference between the two.

I would rather be too careful and bug you all with beginner questions than to screw it up....Because then I'll be asking questions about how to unscrew my screw up!

If you shaped the brace in the dish then I would not worry about how well it conforms to the template. Initially I made two dishes of each radius for myself and have since sold the second as I can use the one dish for all processes and be assured that there will be no discrepancies. Just do a dry run. See if the braces will indeed sit nicely onto your plates in the gobar deck before you glue them. You will be fine.

Shane

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Canada