Gap filling with Gluboost?

[Stray Feathers]

I'm an old dog slow at learning new tricks but I have begun to use Gluboost as a repair tool, having repaired some chipping in an ebony fretboard with ebony sanding dust. It worked very well, and I have had some success with rosewood. But like a lot of glues, the CA seems to darken the natural colour of the sanding dust. It's a real problem with light woods like maple. On my current build I am (again . . .) dealing with small gaps in the maple bindings and b/w purflings on the rosewood back. I think I can get a match for the rosewood. In some cases it would be better to fill the maple rather than the black purfling. Has anyone found a good way to match maple when using CA wicked in to packed maple sanding dust? The Gluboost site says its white tint can't be used alone; has anyone found a way to mix Gluboost colours to match maple? In the past I have tried using whiter wood dust like holly, but it's still noticeable. Thanks - Bruce W.

[Bob Gleason]

I don't work with many light colored woods, but I know it is almost impossible to fill voids invisibly in light wood. My main use for gluBoost is to fix lacquer finish imperfections. GluBoost CA is pretty amazing stuff for some uses, but it is their accelerator that is their best product. It is easy to do a lot of damage with accelerator, but the GluBoost stuff is far more forgiving. Unfortunately, it is more expensive too.For filling voids in binding/purfling, I mostly use shellac and dust instead of CA. I fill the void with dust and then apply shellac on the dust. I sand it wet, being real careful as to the direction I sand in so as not to drag dark colored dust onto light colored wood.. For worst case scenarios, I fill the void with very thin plane shavings, then dust, and finally the shellac.

[John Reid]

Just for fun I played around a bit with a piece of maple binding. Dug out some notches with a chisel and tried several fills as shown. Here’s the results for what they’re worth…

[Stray Feathers]

This is very helpful John - thanks. I was going to do some tests myself and this is a great head start. I considered using bone dust and see now what you have found. I may have overlooked Engelmann dust in the past but it is quite white. I will try some of these same tests with holly too, and I am going to try them also with plain white glue, to see if it darkens less. And I was also considering Bob's suggestion of slivers of maple to reduce some of the gaps - I've done this before but may have better luck with more careful filling. I'll post some results. Bruce W.

[Stray Feathers]

I did a couple of tests and decided not to use Gluboost as some gaps were 1mm wide. In one test I tried using maple dust with white glue and Titebond, and found the glue darkened the patch, but white glue darkened it less. I also tried Black Locust dust, which is lighter and yellower than Maple, and found that when mixed with white glue it was closer to the original maple. (I don't know what will happen when these woods age after exposure to light.) Locust is on the left in the top piece, maple on the right. The middle strip is locust and white glue, bottom is locust and Titebond. I did cut out a bit of white purfling and replaced it, using CA, and it went pretty well, and then filled with some different shades of rosewood dust and Titebond. Patching light wood remains the biggest challenge, just to add to the discussion . . . Bruce W.