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I am searching for an alternative method of side bracing. Something different than the typical wood strips. Is there any fabric strips or something different anyone has tried. If so what is your installation method and pros and cons.

Some of us use bias tape sold for sewing. It is a fabric strip. I glue it on the ribs with hide glue then paint over it with shellac. I use 1" tape about every 4". The linings are just glued right over the top of it.

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Steve Smith
"Music is what feelings sound like"

I need all the help I can get to keep the sides unbowed, so wood strips taller than they are wide are what I use.

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Peter Havriluk

It depends on what you want the side reinforcement to do.

Cloth strips work well in reducing the number and length of cracks in the sides. They can't eliminate them entirely: nothing short of sawing a block out of solid wood and not hollowing it out will do that. The tapes to increase the work it takes to make a crack (by about 50%) and keep them from spreading. When done the way Steve said the tapes will tend to break when the side does, which some have taken as evidence they don't work. However, my measurements do show the strength increase I mentioned, so they're worthwhile. The cotton/poly tapes that he mentioned are what I use. They work better than some nylon tapes I tested at the same time. The nylon was stronger as a material, but tended to come unglued from the wood before they broke, and at a somewhat lower load than the cotton/poly would take.

Wood fillets will help keep the sides flat, particularly in the 'flat' area just south of the waist where you see dishing sometimes. They must be inlet into the liners at the ends. If they stop short of the liners you've got a stress riser, and that's where the side will probably crack when it does: just where it's hardest to fix.

Keep in mind that as a cross grain brace side fillets will not get any shorter as the side shrinks under low humidity. This puts some stress on the side. I have seen a couple of guitars that developed side cracks that ran across the fillet after they were moved into a low humidity situation. It should not be a problem if you have decent humidity control, but....