Official Luthiers Forum!

Getting ready to close the box on my latest. I have not attached side struts/splints to any of my builds yet. There is still time on this one, but was wondering what your thoughts are. Do you use them or not? On this build, I'm using padauk for the back and sides, and it seems a little more splintery than other woods I've used.

I use them. Insurance against cracks. I think some folks are using a type of cloth tape.

I don't.

I use wood side braces, especially when doing thin sides where I want the added stiffness for long term stability. But I make them the full width of the sides, with linings fitted inbetween side braces so there's no stress riser at the edge of the lining.

Cloth tape is convenient because it's thin enough that you can glue the linings right over it, protecting the stress riser without the added work of fitting linings inbetween braces.

I'm not sure if side braces glued after the linings reduces or increases the chance of cracks, but plenty of guitars have been built with them, so it's at least not a surefire recipe for disaster.

I use them. On my latest build I put the braces on the full width of the sides and brought the linings up to them. I reduced my typical width and increased the height increasing the stiffness. I had some slight cupping on one area of the sides which the side braces straightened out.

Very thin wood side splints for me. I use the 1/32" thick planks from the hobby store. Thin enough not to cause stress riser issues.

I've had cracks go right through bias tape, albeit after being dropped.

I cut 1/8 inch strips of scrap from the sides or back, thin them to .050 or a little thinner, and use those. Good use of scraps and inconspicuous.

I used to but I switched to laminated sides and I'm never goin back!

Yes, I use them, helps to stiffen the sides and helps prevent cracks from travelling. I've used Padauk a few times and consider it an excellent tonewood but do also consider it to be prone to cracking and a super candidate for side braces.
Tom

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A person who has never made a mistake has never made anything!!!

Always. Add stiffness, prevent cracks from running, helps keep sides flat (less cupping) making for less work flattening the sides before binding. I think that would be my least favourite task so any help is a plus. And I think they look nice.

Yes, wood side braces inset into linings.
I've used them higher/stiffer to help with sides cupping, and most recent guitar has quite thin bracing, 2 x 10 mm or so with built-up solid linings.
Also have once tried cloth tape, but not so sure about it's ability to halt a crack propagating and it adds nothing to stiffness. Certainly won't help side cupping.
I think I prefer the wooden side struts, mainly for the stiffness, but I've no evidence to back any of this up.

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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.

I use the old style cloth ribbon glued in. I like old school. It really is there to help side cracks from spreading

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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 use strips of 1/4"x1/4" baltic birch ply.

Cloth tape..... and behind the linings.

Everyone, thanks for the replies/advice. I just glued in some thin 0.05 inch splints using some tiger maple left over from a couple of headpiece plates I just recently thinned. I placed them between the kerfed linings so they don't extend vertically the entire heigth of the sides (something I'll correct next time). Although I haven't had a problem with side splts yet (my oldest guitar is only 2 years old), I was anxious about the possibility with the padauk I'm using. Thanks, again.
Marty

I was talking to a local professional luthier and he had something to say against wooden side struts. His view was that when humidity drops wood shrinks much more across the grain than along the grain. So the rib will shrink in the front to back dimension, the side strut won't, the rib is stretched and more likely to crack. Same reasoning could apply to the grain direction of the tail block. I thought about this for a while and decided that I'd seen plenty of side splits due to physical damage but I'm not sure I've ever seen a side split I could put down to changing humidity (backs are a different matter). So yes I still use them. I use spruce offcuts from the front, about 4x2mm. I recently changed from fitting them after gluing the linings to having them full height between the inings.

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"There is hope in honest error .... ". Charles Rennie Mackintosh.
http://www.ianchisholm.co.uk

I don't use them. I used to use them and have tried the cloth tape and thin spruce and other hard woods. Of all the methods I liked the cloth tape the best however I've stopped using it. The reason why I stopped was mentioned above. It makes sense to me that the humidity in theory could have an adverse effect that's why I like the cloth tape but then I don't think the tape would be as affective in stopping cracks... So, I stopped using them. Also have repaired side cracks in many guitars I find it easier to not have to deal with the side braces and have seen one guitar in particular that cracked and separated along the side brace. That was not an easy repair though it probably doesn't happen often.

This argument comes up a lot and honestly I don't think there is a right or wrong answer. Both methods make sense for different reasons. Choose one, market your reasoning, and carry on

Rather than tape I like to use silk with hot hide glue. Hot hide glue loves 100% pure silk. It soaks in to the silk very easily. The combo of silk, spruce and hot hide glue is remarkably strong and light.

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http://www.cushmanguitars.com/.

A man who carries a cat by the tail learns something he can learn in no other way.
Mark Twain

Martin : Once it is dry Padauk is one of the more stable woods with relatively small movement. But it is a brittle wood and blunt force trauma is not a good thing for Padauk.
Tom

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A person who has never made a mistake has never made anything!!!

This is the reason why I inset the ends of the side splints into the lining, and taper the ends of the splints and leave a little bit of room between the end of the splint and the end of the lining notch. Not the best pics but maybe they will help.



I like wooden side splints because they can help flatten out a warped side. I just use leftovers from the sides.

I use poplar side supports and laminate my linings in place. To avoid stress risers the length of my supports are the width of the sides. Then the first layer of the laminated linings is glued between the supports. The second layer of the linings is glued over the supports. Then I carve the linings.

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Ken Franklin
clumsy yet persistent
https://www.kenfranklinukulele.com

Very nice clean work Ken...!!
Tom

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A person who has never made a mistake has never made anything!!!

I use cotton/polyester side tapes. I did some tests years ago and found that it takes significantly more force to crack a taped section of side wood than one with no tape. I've also seen them stop cracks. They won't stop everything, of course, but then, nothing will. I put the tapes on with hot hide glue before the liners so that the liners will hold the ends down. The hide glue was a bit stronger then Titebond in my tests, and much easier to use. They don't interfere with gluing the liners at all.

One issue with cloth reinforcements and hide glue is that air gets at the glue and breaks it down over time. I shellac the side tapes to keep that from happening. We'll find out in 75 years or so whether it worked...

I have seen a couple of guitars with wood side fillets split at reinforcements. It looked as though the humidity had dropped and the sides, which were deep and made of a soft wood, cracked from shrinkage when the fillets didn't shrink.

If you do use wood fillets they MUST be inletted into the liners. If you don't you have a stress riser at the point where the filet meets the liner. That's where the side will crack; just where it's hardest to fix. I was told this by someone who does restoration work at the Met museum in New York.

I use them, and run them up into the linings about .1" to prevent a stress riser if the splint just butted against the linings. I use scraps cut off the sides, or mahogany cut to size. I've not had any problems with humidity, but I do live in an area that is relatively stable all year round.

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Gene

Politicians and diapers must be changed often, and for the same reason- Mark Twain

Al, I remember reading about that years ago. I have been using the cotton/polyester side tapes ever since installed with hide glue and then a coat or two of shellac over the top. Haven't had any sides crack so I can't add anything there.

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Steve Smith
"Music is what feelings sound like"