Official Luthiers Forum!

Anyone prefer fabric side bracing? Anyone hate fabric side bracing? I’ve not done it but I guess I’m pondering it so I’m just asking you who are more experienced what you think.

I do it old school with the ribbon like Martins old ones. Wood or Ribbon they are there mostly for catastrophic damage control

I don't think it matters much tonally but to the traditionalist ribbon is my 1st choice.

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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

Yeah I wasn’t sure if it made much difference with sound or anything. I also wasn’t sure if the fabric had any down side I should consider.

I've done them both ways but now i do them with fabric, it's much faster and easier. I've read articles that seems to show both methods provide an equal amount of protection from splits running down the sides.

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Steve Smith
"Music is what feelings sound like"

I've done both wood braces and cloth side tapes and of the two prefer using the cloth bias binding tape. However, on the next one I think I will use wood veneer strips and sand them thinner where they run under the linings.

Same here and g*bson formerly known as Gibson was side tapes too.

Early on I did wood side braces but like tapes better for ease of application, conforming to the curves and tapes are far more less likely to be knocked loose from a side blow than a stick would be.

Slim when deciding what to use I think it's important to fully understand what we are trying to accomplish here. Tapes and braces both have the same objective and that is to help prevent a side crack and if a side crack happens anyway to arrest the run of the crack so it does not circumnavigate the guitar Brings new meaning to the term "thin line..." . But seriously tapes perform as well as sticks and in my experience can't be knocked completely loose from a side blow but a stick can and I've seen it.

Old school in Lutherie tends to be pragmatic and that's how it got to be old school.

Started with side struts, moved to tapes, now laminating sides so ()hopefully won't need them.

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The name catgut is confusing. There are two explanations for the mix up.

Catgut is an abbreviation of the word cattle gut. Gut strings are made from sheep or goat intestines, in the past even from horse, mule or donkey intestines.

Otherwise it could be from the word kitgut or kitstring. Kit meant fiddle, not kitten.

Started with tapes, now use wood struts that aren’t completely flat and which I use to help impart a very very slight curve across the side, width wise. I use a lot of them at times, too, up to seven or eight per side, run into the linings top and bottom. I don’t think they offer any advantage over tapes RE slowing the progression of side cracks. But perhaps there are some scenarios where a significantly more rigid side can survive a knock without cracking at all? Who knows, I’d use them anyway as one of the things I’m shooting for is rigid sides with a little more mass.

I’ve had someone kindly recommend Wrights Brown bias tape for cloth side bracing so I will probably pick some up and check it out, but I also have some cross stitch fabric that might do well. I plan to lay some sticks down on a scrap piece of wood with just a fabric strip wetted with glue on the ends to glue the sticks down with fabric and see how well it hold after curing. I just want to see how well the cloth clings to the wood and how it behaves for my own curious mind. I plan on HHG, I believe it would be superior in this type of application given how it pulls together.

Same here and g*bson formerly known as Gibson was side tapes too.

Early on I did wood side braces but like tapes better for ease of application, conforming to the curves and tapes are far more less likely to be knocked loose from a side blow than a stick would be.

Slim when deciding what to use I think it's important to fully understand what we are trying to accomplish here. Tapes and braces both have the same objective and that is to help prevent a side crack and if a side crack happens anyway to arrest the run of the crack so it does not circumnavigate the guitar Brings new meaning to the term "thin line..." . But seriously tapes perform as well as sticks and in my experience can't be knocked completely loose from a side blow but a stick can and I've seen it.

Old school in Lutherie tends to be pragmatic and that's how it got to be old school.

Hesh I value your knowledge and opinions so forgive this question if it may seem ignorant, but how would a hhg cloth patch due on the underside of an already cracked top? It might be ugly but not all repairs are idea situations anyways, sometimes more like salvage attempts at times I guess I can’t see cloth strip with glue adding anymore unwanted mass than a spruce strip to a top.

I use bias tape and HHG. My bias tape is 3/4" wide, masking tape on each side makes it easy to do a clean job. I glue on the bias tape then use a small rubber squeegee to remove the excess glue. After the glue is cured I paint the bias tape with shellac.

Wood strips would be a good option if you needed the sides to hold shape.

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Steve Smith
"Music is what feelings sound like"

I use wood braces that are the same thickness as the sides and they run through my laminated linings so that they end up being integral to the linings. I don't think using wood is any more work/time than cloth would be with my process. Also, my supports won't knock loose because they run under the linings. Well, they may get knocked loose but the amount of impact it would take would cause more critical damage than the guitar could stand anyway.

I think the biggest drawback to wood reinforcements is the differential expansion due to changes in RH. My sides will get wider and narrower with swings in RH but the linings will not get longer. That said, I have not noticed any perceptible "bulging" of the sides so it is probably minimal. The cross grain braces on the back would be under more stress from differential expansion than the side braces because the joint is much longer and the braces are much stiffer.

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Bryan Bear PMoMC

Take care of your feet, and your feet will take care of you.

Slim my friend for a top crack the process is:

1). Close the crack with rehumidification and time.

2). Let the instrument reacclimatize to 45% to see if the crack stays closed. If it does not stay closed and/or is an old crack that won't close it's a candidate for filling, more on filling if you ask.

3). If it will stay closed on it's own after reacclimatizing to 45% I wash my hands, don't laugh, ever see a repaired guitar top crack with a dirty line highlighting the crack or for that matter a joined top on an instrument with a highlighted, dark joint? That's debris and someone's dirty hands and glue carrying the dirt into the crack. So I wash my hands and if Titebond is the glue of choice and it usually is for top crack for me I dilute Titebond original 50% with water. I rub the glue into the crack with a hand in the box pressing the crack upward at the same time pumping the crack so the glue migrates into the crack. When I feel and can see with mirrors little tiny beads of glue on the inside I repeat with full strength Titebond.

4). Then it's time to clean up the squeeze out and we use 42 PSI rare earth magnets and plexiglass cauls to flatten the repaired crack and wax paper goes down first to not glue the caul to the guitar....

Now to answer your question but what I just offered was how I get to the crack reinforcement stage that you asked about.

Diamonds are a Luthiers best friend. . Little 1/2" or so spruce diamonds with four 45 degree beveled edged approx .060" thick with the grain running across the top grain are glued every inch or so on the inside across the crack. Kind of like stitches but with glue and only on the inside.

On very rare occasions we have used back joint reinforcement cuts to completely back a nasty crack that won't stay closed.

But you can see there are no tapes or mesh involved in a top crack fix. There could be I suppose but I would be concerned about more mass than diamonds and the difficulty to service if the crack happens again anyway. A diamond comes off easily, tape not so much. Tape is messy too and remember when we are repairing a top crack we are working blind with poor access.

I did some experiments to see how much more force it would take to break a sample side piece with various woods, tapes and glues. Basically, any tape upped the required load by 40% or a bit more. Nylon tapes tended to peel loose rather than breaking, where the bias tapes broke with the wood for the most part. I have had a couple of guitars take hits over the years, and the tapes do stop the cracks from running.

Wood fillets must be inlet into the liners one way or the other. They don't have to be thick to work. I violin making friend of mine pointed out once that repairmen often put a row of wood cleats along a crack. He has seen a lot of old violins with a new crack along the end of the line of cleats: they were too stiff and concentrated stress along that line. He's also seen a lot of cleats that have peeled up for the same reason, but he's never seen a broken cleat: they're always stronger than they need to be. A side brace that's not inlet concentrates stress along the line of the top of the liner, and if the side splits there it's a difficult repair. This from a museum conservator.

I used to wonder in side fillets would shrink less in length than the sides do in depth, which could cause cracks. A few year ago I saw two guitars with just that problem. Both were imports, with solid wood sides of some sort of soft acacia, I believe. They had deep sides, with a single cleat in the flat below the waist, that were properly inlet. Both had cracks along the center of the side, crossing the fillet. I take that as a confirmation.

I know some people glue cloth side bracing with HHG and then paint over them with shellac to give them some moisture resistance. Would it make sense to use a waterproof glue like epoxy instead? what might be the downside?
In a boat building book I read a person used cloth/epoxy in place of fibreglas/epoxy to build a dingy. he claimed it worked fine for such a small boat.

The most difficult side crack repair job I remember doing was one that had side braces in it. I'm not a big fan of them. I have used them in the past too and made the mistake of not tapering the ends to zero or inletting them into the linings and got that stress riser crack on one of my flamenco guitars which was built with very thin sides as flamencos are, hence the reason why I used them. Live and learn.

I am building a few traditional Martin like clones right now and I will tape them. I think tape is a better choice because it's flexible. I have seen guitars with crack in them that I believe was due to side braces with different expansion rates. Tape would move with changes in RH and I think that is good.

I cannot remember what tape I used before but it was really easy. It was a shiny kind of cloth like tape that just stuck nicely to the guitar. I still have the first one I ever built in '92 I believe and the tape is still well stuck in place. For those who tape what do you use?

I use something like this 3/8" double fold bias tape. Open it up and iron it flat so it is 3/4".

https://www.amazon.com/Hobby-Trendy-Double-Cotton-Binding/dp/B08JCPCRSH/ref=sr_1_1_sspa?crid=3E4V3VU7NQHOK&keywords=bias%2Btape%2Bbrown%2B3%2F8%22&qid=1642194778&sprefix=bias%2Btape%2Bbrown%2B3%2F8%2B%2Caps%2C85&sr=8-1-spons&spLa=ZW5jcnlwdGVkUXVhbGlmaWVyPUExUU5ZUU9NNEdHSUEmZW5jcnlwdGVkSWQ9QTA1MDE4MTdTWTgxWVc3SkdRN1gmZW5jcnlwdGVkQWRJZD1BMDU5Mjc1ODFITFg4OENMVDdUOUkmd2lkZ2V0TmFtZT1zcF9hdGYmYWN0aW9uPWNsaWNrUmVkaXJlY3QmZG9Ob3RMb2dDbGljaz10cnVl&th=1 now that's a URL

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Steve Smith
"Music is what feelings sound like"

I used wood side braces (a bunch!) to help control cupped sides. Worked fine, and allowed me to level the sides with a sanding block. The sides were 'encouraged' to flatten against the side braces. Saved the box I was building.

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Peter Havriluk

I used wood side braces (a bunch!) to help control cupped sides. Worked fine, and allowed me to level the sides with a sanding block. The sides were 'encouraged' to flatten against the side braces. Saved the box I was building.

Cloth tape would not have helped to flatten the sides.

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Peter Havriluk

I used bias tape and IIRC (if I recall correctly) there are a couple of tutorials here on the OLF for applying the tapes. Todd Stock did an excellent toot using HHG. I did a toot using Titebond.

I'm also partial to how tapes go under the kerfing making a good assembly. Depending on the builder sticks can be stress risers where they intersect the kerfing if not done correctly.

Regarding using them to save a rim and flatten sides nothing says you can't do both tapes and sticks.

So I just tried to find the toots and can't find either of them but it's pretty simple and intuitive to apply the tapes.

I would iron mine flat since you have to unfold the tape and it has creases. I used thinned Titebond original and just laid them out where I wanted them making sure to keep them straight. I smoothed the wet tape down and move any air bubbles out with my fingers and moved on to the next one. Easy peezy.

If using wooden side braces, please ensure that they continue into the top and back linings, with entry to the lining at the same local stiffness/thickness (as that lining). Butting the side reinforcement against the edge of the lining almost guarantees that even a minor mishap will produce a side crack along the edge of the lining. That crack is a nasty thing to have to fix, as well as costing the customer 2x to 3x what a plain side crack away from structure might run.

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A constellation only takes shape when one maps the whole.
- Beth Brower

I watch a few videos of folks doing it on the YouTube last night it looks easy. I even seen one guy placing dark blue strips with designs like moons and stars or something to math the theme of the instruments, not my style though but interesting option.

This look like the right stuff? I chose mocha because I think it will look good against the walnut.

It's double fold so it will be 1" wide when you open it up otherwise, yes. At least, that's what I use.

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Steve Smith
"Music is what feelings sound like"