Oops. How to fix this...

[Gert van der Does]

This is a cascade of accidents and illinformed decisions...

I replaced a broken trussrod in an early 70s Yamaha FG 365S. That took removing the fretboard. That wasn't hard. But I didn't protect the top sufficiently and didn't pay attention for a couple of seconds so I  caused some semi circular depressions in the top. 

There is no information anywhere on how to fix something like this. I've looked. Months of looking. There's info on the steaming out of dents but that only works with open wood, even if the video says "finished wood" in the title, it's still talking about UNfinished wood.

I tried steaming it. Didn't do much. Then I thought, maybe if I opened the finish and steamed it and then drop fill the holes and fix it... That actually worked for the steaming part. It's level now. However the dropfilling... did not. Superthin superglue did not wick into the holes. I tried opening a couple up a bit further but no dice. VERY visible even with the thinnest superglue I can find.

Second thing there's no info about. Everybody has videos about dropfilling nitro because it "melts into the old layers". Nice. Sounds easy. Very convenient. But 90% of guitars are not painted with nitro and nobody talks about those! I have sought but couldn't find what this Yamaha was made with.. I presume Polyurethane. Could be polyester. Either way no blending into it. The only info out there is drop filling with superglue or gluboost. That's nice but how do they get them to almost totally disappear? Mine didn't. No sense in polishing if it's that obvious.

Now how do I proceed? Invisible is out the window, just wish to control damage as much as possible. 

I'm thinking sanding back and spraying with an airbrush with slightly tinted nitro. I'm really dreading it because so much can go wrong and getting a good tint is really hard.

Upside is I learned a LOT! Some mistakes I will never make again. But I would really appreciate some guidance on how to go on and get this thing back to my brother in law that really misses it.it's from his birth year so it's special.

[Mike Kolb]

You might be right about this being one of those situations where to go forward on your own could be digging the hole deeper than it is now.  Are there any real "hotshot" pro repair folks in the area you could consult with and perhaps get an estimate of repair?

If an intensive repair's out of the question... maybe a whole new top would solve the problem handily?

If that's not feasible, maybe be frank & honest with your brother-in-law about what happened, apologize profusely.... and then begin the search for a replacement guitar.  We've all learned these sort of lessons the hard way.  It'll work out. 

[Roger Häggström]

This is hard work even for a skilled repairman. With a lot of patience gluing in small pieces of wood, with hot hide glue, in the wounds and using dyes to color the new wood, it is possible to make the damage not so in-your-face. But only the best repair magician can make it invisible.

The good news is that the guitar still sounds as good as it did before the mishap.

[Gert van der Does]

Aww, guys. Come on. It's not THAT bad. I barely punctured the finish. They're also not that big. The entire spot is about 1 by 3 inches. 

You guys act like the thing is in pieces. 

[Gert van der Does]

Is there anyone that has a bit of info on repairing some damage on a top with some sort of poly finish?

[Mark McLean]

I have no personal experience with this.

However, I have seen some discussions on woodworking forums about a variety of poly repair resins marketed by Konig (German company - but available worldwide).  Seems to be the go-to product for repairing flooring and piano finishes.  However, you still need to match color and sheen.  Sounds do-able, but not simple.  Might be worth talking to a piano repair person near you?

[Gert van der Does]

Well. I did it. Sanded it back and sprayed nitro on it. The endresult was not perfect but a lot better than those marks.
There were some sanding lines, the edges of the nitro on the poly, that I just couldn't get out but you really need to look hard to see them.
It was a huge relief to finally get it back to the owner. He was happy.

[Mark McLean]

Thanks for telling us about the outcome.  Good to hear that it worked out pretty well, and I will file this story in my memory bank in case a similar one comes my way.

cheers

Mark

[Gert van der Does]

Some pictures. The repaired section is right above neck on the top. Dark and light spots.

First is right after spraying the first number of layers with rattle can Nitro, still sort of wet. In the end it took hundreds of layers.

After a good amount of drying the difference isn't as great anymore and it blends better.

Oh well, it's the best I could do under the circumstances.

[Mark McLean]

That is a surprisingly good outcome.  Well done. 

[Gert van der Does]

Thank you. ☺️