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Cocobolo Problems Anyone Else?


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Hi guys, me again,

i was wondering, it seems as though polyurathane doesnt adhere to cocobolo due to its high oil content. i have made 2 guitars with the stuff, and i must say i think it is impossible for poly to stick to it. on the sides of the fretboards, after the rest is dry, it just rolls off like sticky adhesive from the cocobolo. anyone else had this problem? how is it with other finishes? thank you!

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Yep - very common problem on cocobolo, which many people have experienced here. If it is just a fretboard, I would leave it unfinished - tape it off and finish the back of the neck as you like.

I've gotten pre-catalyzed conversion varnish to cure beautifully on cocobolo, and probably a lot of pre-cat finishes could work in this regard. I've heard that you can use nitro if you first seal the coco with McFadden's rosewood sealer (this is Rick Turner's favorite combo), but I've not tried this myself.

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Shellac might work to seal it.

+2

I just re-read the chapter on shellac in Flexner's book. After chiding folks for not wanting to use shellac as a finish anymore, he went to great lengths to describe it's properties. Among these are that it excells as a sealer to stop sap & oil. It also sticks to any other finish very well, so useing poly over the shellac sealer would be fine.

That being said, I agree with Erik: don't finish or seal it if it's for the fretboard. It's just fine as-is, or maybe with some oil rubbed in.

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Shellac is a great sealer - but lots of posts over on the MIMF demonstrate that even shellac is a hit-or-miss proposition when trying to seal cocobolo.

The problem is that even if you wipe with acetone (NOT naptha which takes too long to completely gas off), the oil will wick back to the surface in about 15 minutes - and anything that takes more than 15 minutes to set up runs the risk of never curing completely. That's why catalyzed finishes work well, they're typically dry to the touch in 10 minutes or less.

Here's a lefty bass I did a refinish on with pre-cat conversion varnish:

JasonRefin32.jpg

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Anyone every try CA to seal the edges of the fretboard? I am assuming you could wipe the thin CA on before finishing the rest of the neck.

I am so allergic to cocobolo I can't even touch the dust so I can't try and report back.

Edited by RestorationAD
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There are plenty of people that will mask off the sides and the face of the FB and then spray. A little tender work with some sandpaper and you can feather the edge right in and never know it was there. Or there is the easy way around the problem and add binding. Then you just mask off the face.

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  • 4 months later...

best bet is to use acetone or MEK, wipe down and immediately spray. other wise you are peein in the wind so to speak. same with glue ups with Coco. Just my observance. I can't even work with it anymore due to it's allergic reactions I get from the oils and dust.

MK

Edited by MiKro
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Same report here, at least in terms of glueing. I've never finished an instrument with Cocobolo as a body/neck wood. Just fingerboards.

I found that for glueing up, a freshly planed face scuffed with low grit paper provides a clean and happy-to-glue surface. I considered the acetone approach as I have bottles of the stuff, but I shyed away and went for a good mechanically-sound bonding surface.

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Anyone every try CA to seal the edges of the fretboard? I am assuming you could wipe the thin CA on before finishing the rest of the neck.

I am so allergic to cocobolo I can't even touch the dust so I can't try and report back.

Probably not a good idea.

The oils bring brown/red color into the CA which could stain the neck wood. If you seal the neck wood first it would work fine probably.

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I really wouldn't think so unless dust contamination so say, maple was a factor. Cocobolo is seriously oily compared to IR. Even the dust gunks up of it's own accord somewhat, whereas other rosewood dusts at least stay dusty for the most part.

Postal - i'm not convinced that CA would wick oils out of the Cocobolo, although sense does dictate erring on the side of caution as it's possible I guess. Acetone definitely sucks out loads of oil and spreads it around, which is a pain if you use it during builds :-\

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