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I don’t think my top is too thin, but I can feel my braces underneath not the x braces, but on both sides of the sound hole ... nothing in the line of strong travel thankfully.
When making the sides and such I used my radius dish through the process.....
It isn’t enough to see... but I can feel it ever so slightly ....
and of course some build pics... these were taken tonight. Hey have a few more FP sessions to go and the final buff out and then ..... it sits















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Gorgeous guitar. One thought I have and it is pure speculation is the pressure you use to level sand is resisting more where the braces are. Sort of like when people make a tracinging of a monument by putting a piece of paper on it and rubbing.

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Good thought...
I DID very lightly use a ROS while sanding ... I could have done it there

And thank you for the compliment. This one has a very “honest “” vibe to it that I have really enjoyed:)


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Long story short, it's because the soundhole braces are more closely aligned with the grain of the top.

Gluing braces with water-based glue pretty much always results in some amount of telegraphing due to wood expansion/contraction, but it's more visible with braces that run in-line with the grain. Sanding is also worse since the wood to either side of the brace flexes much more easily than with a brace going across the grain.

Interesting. Thanks.



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Great looking guitar. FWIW the best sounding guitars I have ever made all have telegraphing braces. The last one I did I used only a scraper and that made them even more pronounced. I would think the ROS would be the best way to prevent that but perhaps not.

Yeah, nice looking guitar! You may already be using them, but I find that sanding blocks can help prevent this from happening. When building these instruments, we are all walking a very fine line.

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George :-)

It would be interesting to know how thick your top is in the soundhole area.

If it is on the thin side, then I would lean toward the braces telegraphing through the top because of tension caused by pulling the top to the sides and humidity changes and the close proximity of the brace following the top grain..

If the top is normal thickness and random orbit sanding, or even hand held paper sanding, was done to the top after the braces were installed my money is on cupping as John said.

Either way she is a beauty!!! And many wonderful, old guitars can show the same thing after time but nobody seems to mind.

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Joe Beaver
Maker of Sawdust

Agreed, sanding.

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Steve Smith
"Music is what feelings sound like"

Thanks for the input guys. I forget exactly how thick I left the top.

So I’m looking ahead. Ho do I avoid this? Just do most sanding before bracing I assume?


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I don't know how most folks do it, but I usually take the external facing side of the top to 220 in the drum sander after the rosette is installed and leveled. I will put a wash coat of shellac on there to try to protect it a bit for the rest of the process. If I have to take any thickness off I take it off the internal facing side of the top. Afterward take it to 320 with a block.

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ROS's are very good at removing material, sometimes to good. I use mine only when 'roughing out' material. If I feel the need to power sand once I'm getting close I use a quarter sheet sander. Slower but safer

I do remember way back when, I was leveling binding. I figured I was getting pretty good at this and thought, why not use the ROS? I nearly sanded through the side and binding in a spot or two before I came to my senses.

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Joe Beaver
Maker of Sawdust

I have had this happen when the humidity changes

Ed

Thanks for the reply.
This guitar has been built and wood stored before building in the same room. RH is 41-45% constant.
Good thought though!


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When I first got mine I sanded right through the rosette purfling and went O.o

A lesson in retoping was in order.

Now I know how to control it though and it does a fantastic job fast.