True-oil Cocobolo

[sully75]

Hi there

I have two classical guitars that are getting near the finishing stages.

I used Cocobolo on both of them and didn't anticipate that it might cause issues.

One guitar has a wide rosette I made out of cocobolo tiles on a spruce top.

The other one has a Maple neck with cocobolo headplates on the Front and back of the headstock.

Now I'm learning that true-oil doesn't work on cocobolo.

I'd rather not french polish these guitars if possible (they've been sitting around for a year and I just want to get them done).

I was thinking about doing pore filling with zpoxy on the cocobolo to seal them and then doing true oil over that but not sure if that would work? Or masking them off and leaving them unfinished and then just polishing them when I do the final polish of the true oil.

Or a super glue fill?

I'm also concerned that if the true-oil (or whatever finish I use) hits the cocobolo, it's going to stain the top and the maple neck.

Open to all suggestions, thanks!

[cobalt60]

Hope you kept some scraps, if so your best bet is to test ANY option before applying it to the instrument. Cocobolo is aggressively oily but also varies a lot in its properties board-to-board.

Correct that applying an oil to cocobolo can end in a finish that never dries.

In my experience, a spit coat of shellac - like you'd do to start a french polish - is a great starting point and base for final finish coat, as it seems to suppress the oil while still creating a surface that finishes nice and clear.


But yeah, I'm pretty sure cocobolo is top of the list of woods people curse for dulling tools, being unexpectedly dense, having unexpected grain direction shifts, and ... needing special treatment to ensure a nice finish.

[yellowesty]

I've had success using Tru-Oil on cocobolo by washing the cocobolo surface carefully, thoroughly, and repeatedly with acetone immediately before wiping with Tru-Oil. Some spots on the cocobolo may still ooze a bit of resin (?) through the Tru-Oil. After a couple of hours to allow the Tru-Oil to dry over the rest of the cocobolo surface, the offending areas can be scrubbed with acetone and recovered with Tru-Oil. Several repetitions may be needed before a good Tru-Oil foundation (for further applications of Tru-Oil) is achieved, but it can be done. The whole process is a bit tedious, but it gives good results. (I now tend to avoid cocobolo.)

[sully75]

Originally Posted by cobalt60

Hope you kept some scraps, if so your best bet is to test ANY option before applying it to the instrument. Cocobolo is aggressively oily but also varies a lot in its properties board-to-board.

Correct that applying an oil to cocobolo can end in a finish that never dries.

In my experience, a spit coat of shellac - like you'd do to start a french polish - is a great starting point and base for final finish coat, as it seems to suppress the oil while still creating a surface that finishes nice and clear.


But yeah, I'm pretty sure cocobolo is top of the list of woods people curse for dulling tools, being unexpectedly dense, having unexpected grain direction shifts, and ... needing special treatment to ensure a nice finish.

So can I seal the cocobolo and mahogany with french polish and then true oil over that? I'm leaning more towards sealing it with zpoxy.

[Quickstep192]

Just a word of caution...

When washing oily woods with acetone, I’ve had color from the wood bleed onto and stain lighter nearby woods.

[cobalt60]

Yes and that sort of color contamination is true for the first few passes of shellac as well. OP said his guitar is assembled, so in his case, I might think a wipe (with acetone or alcohol) might lead to massive color smearing.

I mean, color-bleed is always possible with any woods during the first passes, but cocobolo is, as usual, one of the worst.

[Simon Fay]

You will likely have issues if you don't use a sealer. The epoxy pore-fill should work well for this application. Personally, I would pore-fill and then wipe on a few seal coats of shellac just to be safe.