Minor damage to back, what are these woods I'm seeing?

[Henri3794]

I have here an older yamaha fg400a. (Fern on headstock, not dove). It took a bash to the binding in the back, so I ignorantly sanded it down to buff it out and soon realized I was already through the first layer of wood.

My question is, what woods am in seeing here? I assume the dark, thin layer is the actual back panel, and the light color is some kind of interior binding, but according to what I know about that area of the guitar, I should have sanded right through!

Any insight regarding how close I am to putting a hole in my guitar, and what woods are being exposed would be great. Also, does that look like mahogany or a cheap nato? I've played a few high end martins, and this guy really holds its own so it got me wondering...

Thanks!

Here is the picture...

http://imgur.com/cvLKSDu

[AllThumbsBruce]

Looks like you have a laminated wood back and have sanded through the outer two layers. It is unclear from your picture, but you might have sanded right through the back and down to the kerfed lining, which would be the light colored wood. However, I think most laminated guitars are three layers, and if the light colored wood is the kerfed lining, then I only see two of the laminated wood layers of the back. So maybe post a picture of a side view.

In any case, I think this will be tough to repair.

On second thought, maybe you have just sanded through the finish and the outer layer.

[jaybones]

Looks like you've gone through the finish and stain, a layer of thin mahogany to a layer of whatever light colored wood they would have used. Spruce, pine, or even birch, and since this is a Yamaha it could be some Japanese equivalent of a light wood we don't have a name for.

Also, looks like you were sanding on the contour of the body, probably trying to get rid of the damage the bash had done. When I sand wood, I always go WITH the grain, never across it.

You probably have more than enough layers to go before you sand a hole in your guitar. Since its on the back, you should seal it up with a light coat of poly and call it a day. Several light coats letting it dry fully before any buffing or light wet sanding will be better than fewer heavier coats, both cosmetically and for functionality.

If you leave the grain exposed like that, moisture will quickly get into the wood fibers and then the plies will start to delaminate. That's an even worse problem than some cosmetic damage.

[mirwa]

You have a cross laminated back. Usually they are a 3 or 5 ply

It's cheaper and stronger so manufacturers sometimes do this

You can simply paint it darker to hide it, or apply a veneer over the area and recolour it, have a photo of one we did recently if it helps

Steve

[Wade Hampton]

Originally Posted by mirwa

You have a cross laminated back. Usually they are a 3 or 5 ply

It's cheaper and stronger so manufacturers sometimes do this

You can simply paint it darker to hide it, or apply a veneer over the area and recolour it, have a photo of one we did recently if it helps

Right. Henri hasn't yet reached the kerfed lining, which is kerfed, meaning there are little slots cut in it like this:

Mirwa, your suggestion is better and more creative than mine would have been, which probably would have been along the lines of: "Oops - look like you screwed up there, buddy."

Which OP already knows, so it would have added nothing to the solution to the problem. But what mirwa is suggesting, OP, if I have it right, is that you get some paper thin wood veneer and cut it into a patch to cover where you blew through the first layer of the laminate.

You're never going to get it to match exactly, even if you got the same species of wood as the outer layer. So you might as well go for a nice contrast, like a thin layer of rosewood veneer. Cut it into an attractive symmetrical shape, glue it down, and apply some sort of finish. I'd probably use some sort of oil if I was doing it.

Hope this helps.


Wade Hampton Miller

[cooper59]

looks to me like you just went thru the finish. I don't see where you went thru wood.

[roylor4]

I would just stain it and leave it be. The stain will likely take to some areas better than others and it will show variations in the darkness but its far better than what you have now. A veneer will show too unless you do the entire back.

Stain it and consider it a "tuition in the school of life".

[Henri3794]

Thanks all for the replies. You'be all been very helpful a d I'm bow confidant that I'm not about to punch a hole in my guitar. I am fine with a come imperfectjon, but like previously mentioned, I will defiantly seal the exposed area to prevent moisture damage.

Thanks again guys, I appreciate all of the input.

[Lacks Focus]

Originally Posted by cooper59

looks to me like you just went thru the finish. I don't see where you went thru wood.

At the lightest color section, the grain is running side-to-side, or perpendicular to the finish surface grain, a pretty clear indication that the veneer layer has been removed and they're into the next layer down.

[mirwa]

Originally Posted by Wade Hampton

Mirwa, your suggestion is better and more creative

An example of what I was talking about, the hole is first repaired, then we lay a laminate of the same type of wood with the grain running in a similiar direction over the repair. From there, you colour build just that area, and then remove the tape and blend the two together

Steve

[Magnumb]

Originally Posted by cooper59

looks to me like you just went thru the finish. I don't see where you went thru wood.

I agree- I have a FG-403S and the tinted finish (the size of a baby fingernail) chipped off the back of the headstock, leaving bare Nato (Nyatoh) wood. I just put a couple of layers of clear nail lacquer over it to seal and prevent spreading.