Drop fill is darker

[Gert van der Does]

I have a 70s Yamaha with a bit of a restore. It has some chips and cracks on the edge of the spruce top which I drop filled some CA on. Those chips were feathered wood and they colored way darker than the finished wood.  It's almost orange. Tried another patch with polyurethane laquer, came out the same discoloration.

What went wrong there? Will this fade again? Anything I can do about it?

I've been seeing people drop fill for ages, nobody ever talked about this.

[Greg Mirken]

I think it's too late to do anything about it now. The fractured wood fibers act like a paintbrush and suck up the medium. You can prevent darkening by first sizing the damaged spot with thinned glue [either hide or Titebond works]. Let the glue dry, then do your drop-fill.

[Gert van der Does]

Darn. Was afraid of that. 

I could scrape the fill out but I'm afraid the cure will be worse than the disease. I guess he'll have to live with it. At least it won't get worse.

[Palle Clausen]

Most brands of CA-glue, will discolor the wood.

I use CA-glue from JET. It doesn't discolor the wood. I am also told that GluBoost and the one StewMac sells, are safe to use.

Otherwise, the method Greg describes, will also prevent discoloring.

[Gert van der Does]

Being in Europe, I don't have easy access to those brands.

I also think it's more the feathering of the wood that does the coloring than the brand of glue. 

Thanks anyway!

[Mark Fogleman]

https://www.voerman.nl/index.php/gluboost/gluboost-eu-info

[Greg Mirken]

I agree, Gert. I haven't used either GluBoost or JET's CA, but in my experience anything will suck into the fibers and darken the fractured wood. You have the same issue with lacquer or shellac, for example. You can simulate what it will look like by wetting the damage with naphtha.

[Gert van der Does]

I tried both CA glue and polyurethane, not the water based one, the spirit based one.
Both had the same effect. Since this guitar was originally finished in poly, I found it odd that totally different substances had the same effect. If I just wet the same wood with water it is much darker too.
Just curious what you all do to prevent that when doing drop fills.

[Palle Clausen]

See first reply by Greg. It works.

[Greg Mirken]

It works so well that I have gotten over-zealous with glue sizing and wound up with a repair that's paler than the surrounding finish.