Using CA Glue or Epoxy to Fill Divots?

[ThreeChordWonder]

Got a small problem on the back of the DIY thinline P90 body I've been working on.

The front is fine, loverly in fact, but theres some damage on the end of the lower bout.

It's either sander rash or the wood got too "wet" and there is some scoring in the grain.

Thinking CA glue or clear epoxy as a filler. I don't think wood filler will stick.

Don't want to use anything that will react with the clear polyurethane, just fill the divots so the finished surface is flat and shiny.

What say you lot?

[Top-L]

Is that finished? Wouldn't proper operating procedure be to fill before finishing?

[ThreeChordWonder]

Divots appeared DURING finishing.

[Top-L]

Divots appeared DURING finishing.

My guess is that whoever finished it, didn't use a sealer and the wood drank the topcoat.

I would remove the finish and start over.

[ThreeChordWonder]

^That's not happening.

The polyurethane is the sealer. It's intended to go onto raw wood and to partially soak in. The only explanation I have is that some water got into the end grain while I was wet sanding the edge after spraying it black. I did that because the end grain was soaking up more stain than the side-on grain.

I'm asking for help, not criticism.

[Top-L]

^That's not happening.

The polyurethane is the sealer. It's intended to go onto raw wood and to partially soak in. The only explanation I have is that some water got into the end grain while I was wet sanding the edge after spraying it black. I did that because the end grain was soaking up more stain than the side-on grain.

I'm asking for help, not criticism.

I'm an amateur woodworker and mistakes happen all the time. I'm not criticizing you, just stating the obvious, that if you want it to be right, you have to start over.

There are woodworking forums where people will give you better advice than a pickup forum. I'm sorry it didn't turn out the way you wanted. My amateur opinion is that caking some kind of filler on top of the finish will make it worse. It appears that there are bigger problems on this piece.

Over the years I have read a number of threads where someone realize finishing a guitar is beyond their abilities and they send it to a luthier (who removes said finish and starts over).

The saying "you can't polish a turd" applies here.

[Securb]

I would ignore it and play the hell out of the guitar. My guitars are not museum pieces they are players. Dings, dents, and scratches are part of their character.

[ThreeChordWonder]

^ That I like, but if I were a perfectionist...

[JamesPaul]

I'm with Securb. Who sees the back of your guitar, other than you? Sooner or later, they all get some wear.

Sort out how to avoid it next build and play it as is!

[GuitarDoc]

^That's not happening.

The polyurethane is the sealer. It's intended to go onto raw wood and to partially soak in. The only explanation I have is that some water got into the end grain while I was wet sanding the edge after spraying it black. I did that because the end grain was soaking up more stain than the side-on grain.

I'm asking for help, not criticism.

Oh darn. And just when I was getting all prepared to be really critical. What a killjoy!

[GuitarDoc]

You could use either epoxy or CA glue, they both will fill that void and stick just fine. You'd probably need to use more coats of CA than epoxy though and epoxy takes much longer to cure than CA, so there is some trade-off with either. If you plan on painting it a solid color you'll be fine, but if not, no matter how smooth you finish/sand it, the defect will show through.

[Mincer]

You will see something there filling it after the fact. I think it is part of the guitar's story, so just rock it.

[ErikH]

If you want it perfect, strip the back and do over, just the back though. No need to really redo the whole body. Is this ash? That'll soak up a lot of finish without grain filler. Lay a coat, let it sit for 10 minutes, lay another coat, let it sit for 10 minutes. It may take several coats but look at it between each coat. If you see a problem, remedy it and then move forward.

There is zero need to wet sand a filler coat. That will leave nothing for the clear (top) coat to grab a hold of. Wet sanding is part of the final top coat smoothing processes before buffing. And before any of that, the body needs to cure for 2 weeks minimum. Labels that say "2 hours to touch" or similar mean that the very top surface of the finish layer is dry enough to touch, but it has not fully cured. That takes weeks to happen.

[GuitarDoc]

I let my final clear coat (which includes 10-14 total clear coats over a 5-10 day spraying period) cure at least 3-4 weeks before final sanding and polishing.

[Dudeman7]

I have used super glue to fill damaged poly finishes and I always end up regretting it. There is almost always cloudiness that spreads beyond the initial damaged area into the surrounding polyurethane. That becomes another thing to fixate on and have to deal with.

Either starting over or doing nothing would be better than trying to fill that with glue, IMO.

How does the rest of the guitar look? Do you have any full pics?