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I am ready for finish on an oak J-185. The instrument is 4-1/2" thick at the neck and 4-7/8" thick at the heel. The sides were thinned to .070 and bent, and they ended up very flat so did not need much work to flatten them - in my limited experience.

Just below the waist where the sides are close to straight for a time as they transition from the reverse curve of the waist to the curve of the lower bout, there is some flex in the center of the sides. I can easily bend the wood in with my thumb. Is this to be expected in a larger, deeper guitar?

right about where the end of the sanding tube is in this picture:

https://www.flickr.com/photos/ruby1638/17705417393/in/album-72157649776959267/

Ed

Hi Ed
On deep guitars like this I have always use side splints, perhaps ten or a dozen around the
perimeter. The area where you are flexing is in danger any time someone places the guitar
in their lap with keys or the like in their pocket and at .070 " especially so. If you used side
splints I would only worry about the area in question. My fix would be to laminate a thin veneer,
.040 or so, as reinforcement. As gluing would be problematic I would maybe consider using a
laminating epoxy such as West System 105 resin that cures glass hard. If no side splints I would
consider trying to work some in especially in the lower bout. I'm sure you'll get it sussed out.

Ken

That is the weak spot on all guitars. I have used .07 and thinner b 4 and in addition to stiffer side braces, I put a "big ol" brace right in that spot. It has worked great!

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Pat

Thanks Pat and Ken - easy enough to do to ensure no embarrassment in the future.

Ed

"Big ole brace" is right at that area, but why make oak sides at .070"? They bend quite nicely at .085-.090". Just use SS2...