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Have you ever observed this before? I've seen telegraphing before, mostly on classical guitar fan braces but this is different. There is no deformation at all just visible shadow like lines where the bracing is. Could it be the glue used? Over clamping of the braces? IDK?

The guitar BTW is in for repair and was hand built by someone. My customer bought it off of ebay. Good sounding guitar but not well built.

I have heard this phenomenon was called telegraphing
You might have better luck searching for that
Tom

My guess is that it happened while level sanding the amber toned finish.

Now that's a good hypothesis!

I think I understood telegraphing to be an actual deformation feature. I see this on most of the classical guitars I have built over time, not a bad thing per se, but it's an actual rise and fall between the braces. This is a discoloration of the top right on the brace lines. But perhaps the term is used equally.

Yep, I did that on one by sanding with too heavy a hand. Created a lighter area in the finish over each brace.

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Steve Smith
"Music is what feelings sound like"

I can't see that picture but I remember reading about an issue with a certain type of glue that IIRC was RF cured or something like that. I can't remember much about what I read but I seem to remember you could see the brace outline even though the top wasn't deformed.

I suppose the sanding issue is more likely given it is not from a factory but the maker could have had access to this glue system.

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Bryan Bear PMoMC

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

Something wrong with the images in this post -- can't see them and the scroll area is double the page width.

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Ken Cierp

http://www.kennethmichaelguitars.com/

Sorry about the image, these Google Plus images drive me nuts, some can see them some can't, permissions all over the place I don't get it. Anyway try this link maybe?

https://goo.gl/photos/bAJwXp5xPYCx2sus7

Wow! I was imagining something way more subtle. That's really blatant. With proper marketing skills, that might be turned into a feature.

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Once in a while you get shown the light in the strangest of places if you look at it right - Robert Hunter

Gonna take a SWAG here, that the finish applied to the top has an amber cast to it, and block sanding the finish on the top caused the finish over the braces to be thinner than the finish over the open area and that shows up in a lighter (thinner) finish over the braces. How to resolve? No idea. Maybe there's a whole lot of finish applied? And hand-sanding between the brace shadows might level the finish?

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Peter Havriluk

"Good sounding guitar but not well built."

Stella!

Is that glue squeeze out below the bridge? I assume there were some structural issues other than just the cosmetic ones?

It might be squeeze out. The neck joint has gaps all around the cheeks and the neck angle was probably slightly forward but the fretboard was glued on dead flat so there is a gap between the bottom of the FB and the neck from about the 9th fret through the body joint to the end. It seems to be holding though. But it's not anything that I would ever release into the wild. It's marked inside as being the builders 19th guitar.

In all fairness I don't know if this guitar suffered some damage and was just poorly repaired though.

It's always interesting to get a custom guitar in the shop. Something I can compare my own work too. I sort of suffer from self criticism and often times don't think I'm a very good guitar builder, especially when seeing the work of others for example on this forum, but in this case my work stands out

But in the end it actually does sound pretty good and my customer paid a 'fair' price for it. I'm not one to criticize looks or finish flaws but i don't like structural flaws.

Also to be clear the only reason why I started this tread was because I was curious to understand this ghosting problem so I won't do it myself some day not to be critical.

And I'm glad you did. I don't do any tinted finishes but someday I may. I would never have thought of the possibility of sanding the tint thinner over the stiff braces until this thread. I'll keep that in mind going forward.

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Bryan Bear PMoMC

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

This happened to me on my first build. I used liquid hide glue and a waterbase varnish (Varathane IRRC). I think the hide glue additive that keeps it liquid migrate through the top and react with the finish somehow.

"I would never have thought of the possibility of sanding the tint thinner over the stiff braces until this thread."

There seems to be an admonition to new builders to build "light" to get a responsive guitar. Reducing the size of the braces and thinning the scantlings of the back and sides. Like hopping homebrew, It often only shows up as too much in the finished product.
If the braces have formed "hard points" enough to cause "ghosting" from level sanding the finish my guess is the top is rather thin. Some build for today, some build for tomorrow, but the trick is to build something for today that will still be here tomorrow.

I have a different thought that doesn't contradict your concern of people building too thin,

A brace is going to locally distort the top or it isn't doing its job. After all it is shaping the direction of the top -at the brace's location- and in between braces any top will have some deformation.

I think that when "level sanding" some people aren't actually level sanding. I make sure that I have at least a wash coat of shellac on for this task, and then sand with a flat block until all shellac is gone. That levels the valleys between the braces, and I don't get brace telegraphing after that point, and I've kept some guitars for a number of years.

It always takes more sanding then I would suspect to get to that flat condition, and I suspect without using something like shellac as a "tell" that people aren't ever truly getting the top level sanded and the final finish makes the brace distortion stand out,
Mike

What did u seal top with?

Without seeing the guitar in person it is rather difficult to say exactly what is causing the lightness over the braces on this guitar but I have seen something very similar on guitars I have sprayed in lacquer as well as on cars. I think it could be blushing. (moisture trapped in the finish) If the guitar was in a climate controlled shop and moved into a different environment (spray booth) to be sprayed it is possible the builder did not let the guitar acclimate to the new environment. The top wood will acclimate faster than the braces so you will end up getting blushing directly over the braces. If the builder didn't know how to fix the problem he may have just left it and kept spraying more coats thinking it would go away or buff out.

As I said, I have seen this on a couple of guitars I have finished as well as my years spraying cars. Cars will do this quite frequently at every panel that has any structure behind it. The only way to eliminate it is to use a hotter thinner to remove the blushing and/or wait for a less humid day to spray.

Again, without seeing it in person it is hard to tell if it is blushing or sanded through as was suggested above. Blushing sometimes will have a slightly blue cast to it but it can also just appear as a lighter hazy patch. Sanding will usually leave a tell-tale sign of sanding scratches (you may have to look at it under magnification to tell).

That is my take on what it could be.

Bob

I have seen this happen, so this would be my hypothesis as well........

Interesting. Another good idea.

I once had that issue while finishing. It was a nitro finish and the humidity was too high. The next coat of finish made it invisible .


Sent from my iPhone using Tapatalk Pro

I finally saw the image (on tapatalk). I was surprised by how well it followed the brace patters. Since sanding the color coat slightly more over the braces was the prevailing theory, I expected to see less color in-between areas where two braces intersected. My thought was that the area near the corner of two brace intersections would be much stiffer than the area beyond that; I would expect there to be a fairly large area of transition where the color difference isn't so stark.

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Bryan Bear PMoMC

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

Gibson made a lot of guitars like that. As I remember it was late sixties, early seventies and they blamed the new scientific glued that was cured by... some strange process. You could see the location of the braces clear as day.

I mentioned that earlier but could not for the life of me remember where I read about it or find it anywhere during an (admittedly brief) internet search. I'm glad you said this; I was starting to think I dreamed it. If I remember correctly, it was regular wood glue but rapidly cured with radio frequency. I could be off on that though. I also can't remember if an explanation of what was happening was ever offered.

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Bryan Bear PMoMC

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