View Full Version : What Polyurethane for Fretboard?

07-12-2010, 03:46 PM
I've been tinkering with one of my ukuleles. I replaced the maple fret markers with abalone ones.

While I am at it, I'm buffing out the top and headstock a little more.

Finally, I want to put a coat of satin polyurethane on the fret board because there are a couple of areas that are worn.

The fretboard is koa and it came coated with a polyurethane. I have already smoothed everything out pretty well with 1500 grit and 0000 steel wool.

I am planning to brush a coat or two on and use 0000 steel wool to smooth it out.

What I'm not sure of is the brand of polyurethane and I should sure use. I've seen some oil and water based polyurethane. If anyone can suggest a particular brand I would appreciate it.

Thanks for any help!


dave g
07-13-2010, 05:46 AM
The fretboard really ought to have an oil finish of some sort on it - something that soaks in, rather than something that forms a layer on top. Varnish would look nice at first, but would start to look like crap as time passed because you would wear completely through in places.

Edit: Doh! Sorry, I missed the part about it already being varnished. Never mind :)

07-13-2010, 06:34 PM
I don't see where he said it was already varnished, only that it's worn in spots. I'd buff the whole fretboard smooth and oil it.

Question: Is there evidence of Ebony colored dye that's rubbing off leaving light colored spots? Or is it just looking ratty from normal wear and tear? If the fretboard wood isn't dark but it's been "painted" that way, look in the guitar/violin/instrument catalogs for ebony dye.

Fiebing Dye (black) is what Stewart Mac sells as fretboard dye. It's mostly used in leatherwork for dying saddles. You can buy it online from a leather supply house for about half what Stew-Mac charges.

Here's a "How To" article on it's use from Stewart Macdonald


07-14-2010, 04:44 AM
The fretboard is koa. It already has a polyurethane finish on it.

I've done some reasearch on this and I can use an oil or water based polyurethane. There is even a wipe-on.

I think KoAloha uses a polyester as does Rickenbacker on their guitar fretboards. I'm not sure what Kamaka does.

I would imagine this is not that different from Fender maple guitar boards where the finish wears through.

Since this really isn't a build quiestion, this may not be the right forum. I may re-post it in Uke Tech Support.



07-14-2010, 05:43 AM
I never liked the Fender maple fretboards. Maybe that's why.

Anyway, I think you're probably in the best forum already. Thanks for the additional details. At least now we don't have to guess what you're working with.

EDIT: I guess I missed what you said about it being a Koa fretboard. Otherwise I never would have mentioned dyeing it.

07-16-2010, 06:06 PM
I'd rub the fretboard down with 0000 steel wool and oil it with a proper fingerboard oil. Koa is an open grained wood, hard to believe it would look good in poly without first filling the grain.

07-16-2010, 10:04 PM
If there is already varnish on it, I would take it down to the wood and use oil on it.

And normally I would not recommend using steel wool on an open grained wood. You could end up with a fretboard filled with glitter from tiny bits of the steel wool that embed themselves into the grain. And I don't mean resting in the pores and you give 'er a tap on the back and all the glitter falls to the floor. We've tried everything, even super high-power magnets... no luck, the glitter is still stuck in there. Better to get yourself some good sanding pads before you start.

07-16-2010, 11:15 PM
I used various micro fine sanding sticks to take the varnish etc. off of a couple of older ukes, I like the look and natural wood and the varnish had worn through and looked crummy as it had aged anyway. I did it to my old Kamaka too and got the finger spots off and a lot of grime and polished the frets. These are the super super fine finishing sticks (slender pads that look like fat nail files with a different fineness on each side). It was extremely minimal! But now it looks much nicer and it didn't affect the mojo any. ;)

07-17-2010, 03:50 PM
I like the idea of sanding off the finish. I think I'll use a 400 grit and see how it goes. I'm not sure I'll know when I make it through the finish.

I've always used lemon oil on rosewood and ebony boards. Any suggestions for koa?

As for polyurethane, it seems that the oil based ones have taken some hits with environmental controls lately.

Original Defthane and Varathane Professional are gone from the shelves in California and I understand from the rest of the country come December.



07-18-2010, 11:03 AM
Thanks everyone for the advice!

I used 400 grit and lemon oil a few times and then 600 and oil and finished it off with 1500 and oil.

If you turn the board at the right angle you can still see a little finish in the pores and it was tough next to the frets, but unless you are inspecting the fretboard and looking for it, it is not noticeable.

This will be a lot easier to maintain.