Side reinforcement strips

[Mike Perez]

Hello,
In 1983 I made my first steel string acoustic. It is mahogany. I forgot to glue any side reinforcement strips and now it has developed a small split on a side. Since I want to refinish it, I thought it the best time to add the strips. Since clamps are not possible and any wedges very impractical, I thought of using very thick CA glue and holding them in place until the glue holds.
Any ideas/suggestions on how to go about this job?
Thank you.
Mike

[Barry Daniels]

I made some plexiglass cauls with rare earth magnets for this task. One for the inside and one on the outside. That way I can use Titebond or even HHG.

[Alan Carruth]

Cloth side tapes work very well in resisting splits from knocks on the side. In measurements I made they increased the force required to crack a sample piece by about 50%. They also do a good job of stopping cracks from spreading, which simplifies repairs; the crack stops at the next tape, rather than running the whole length of the side. They don't make the sides any stiffer, of course.

Wood side reinforcements must be inlet into the linings at either end. If they aren't they produce a stress riser where they meet the liner, and you end up with a crack that runs right along the joint between the liner and the side, which is very hard to fix. The only easy way to do this is to put them on before the liners, and it's too late for that now. Tapes, on the other hand, don't cause that problem, although it's still best to put them on before the liners so that the ends are held down and can't peel up later.

Side splints don't shrink as much in length as the sides do in width when the guitar dries out. This can cause the sides to crack, and I've seen this.

SO; under the circumstances, side tapes are your best bet. I've been using cotton-poly bias selvedge tapes for this for decades, and they are fairly easy to use and work well. Cotton glues better than synthetics, but the polyester is stronger, so the blend is good. I use hot hide glue as it's easier to use in now construction and marginally stronger, but Titebond works well too. With Titebond I dampen the tape, work in glue with my fingers, and apply it where I want it. The extra water gives you more working time, but doesn't seem to reduce the strength of the bond to speak of. Press the tapes down with your finger tips and work out any wrinkles or bubbles.

I used to do repairs for a touring musician. He'd come in about every three months with a couple of more side cracks in his D-28. They had used some sort of self-adhesive tapes on the sides. The rubbery glue didn't really hold them in well enough to prevent cracks, and it dried out over time, so the tapes ended up flapping loose, covered with dust on the sticky side. After a few go-rounds I stripped off all the original tapes, cleaned up the gick as best I could, and replaced them with cloth tapes. I got a lot fewer visits after that, and none of those involved side cracks.

[Doug Shaker]

I use linen tape along the lines of this stuff:
https://burnleyandtrowbridge.com/produc ... 8516870231

I dye it oxblood first, just because I want it to look interesting if someone is poking around inside one of my guitars.
https://www.dharmatrading.com/dyes/dhar ... =dyes.html

Then I glue it in with hot hide glue. Under the linings, if I can, clamping the crap out of it to make it as flat and
as thin as possible. Works great and it makes my guitars just a smidge lighter.

Doug Shaker

[Bob Francis]

I made some plexiglass cauls with rare earth magnets for this task. One for the inside and one on the outside. That way I can use Titebond or even HHG.

You need to publish a book of all the jigs you have done!

[Barry Daniels]

It may sound weird but I have more joy making and designing jigs. Sort of the engineer side of my brain taking over. Check out my binding jig that I just re-designed. It is the only binding jig that I have seen with linear advancement in both axis with one thousandth inch accuracy. Sorry for going off-topic.

[Glenn Howland]

I'm making my first guitar and am experimenting with maple side reinforcement strips. They are under the linings and run from rim to rim. The kerfed bits covering them are a bit awkward; I may redo them before committing to the top / back glue up. The neck block in this pic is scheduled to lose a bunch of weight, as I'll be countersinking bolts for the neck with a good sized forstner bit to make a channel.

[Clay Schaeffer]

A third choice for adding side reinforcement is to use wood veneer strips glued cross grain to the sides. Using a razor knife or sharp chisel you could cut small recesses in the linings, then bend the veneer to tuck it into the recesses and avoid the "dreaded stress riser". Thin wood veneer strips are less likely to restrain the sides from moving as much as side splints, so are less likely to cause cracks in the sides if the guitar experiences - extremely - dry conditions.

[Alan Carruth]

I'd still run the ends under notched liners to avoid the stress riser.

[Darrel Friesen]

Detail.jpgReady for the next phase.jpgI'm making my first guitar and am experimenting with maple side reinforcement strips. They are under the linings and run from rim to rim. The kerfed bits covering them are a bit awkward; I may redo them before committing to the top / back glue up. The neck block in this pic is scheduled to lose a bunch of weight, as I'll be countersinking bolts for the neck with a good sized forstner bit to make a channel.

Maple is fine but spruce is lighter and just as effective. I can't really tell from your picture, but just carefully pare the kerfed bits with a chisel to match the width and profile of the rest of your lining.