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The customer wants an oil finish, which I have never done on a guitar before. I have experience oil finishing furniture many years ago, but some research suggests it's a little more complicated for a fine musical instrument!

I tried using my water based filler from Stew-Mac, and didn't like the color it turned the lighter wood. Never really liked that stuff anyway. Then I tried the micro balloon natural color filler from LMI and didn't like that either, it also gave the wood a greenish tinge. So I sanded it off, and am now thinking of trying shellac and pumice, and sanding it back to the wood, then maybe a thin coat of shellac, followed by Tru-oil.

Another option is epoxy, I have both the West system and zpoxy, but don't have experience with how that might affect the oil look. The Koa is highly flamed, and I think will have an incredible depth with an oil finish, the pores are relatively small compared to rosewood or mahogany, though the binding here is rosewood. I also know I don't necessarily have to fill pores with an oil finish, but I am not sure if I would like that look or not, and it's hard to tell from a scrap piece how a whole guitar might look.

I am going to try some experiments on some scrap, but would like to get some long term consideration suggestions from you more experienced folks, and any other suggestions!

thanks,
Damon

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Damon Wack
https://www.facebook.com/LindamonGuitars

I never pore filled for oil finishes.
But maybe that's just me.

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"Act your age, not your shoe size" - Prince

I have had the same experience with wood fillers, I just don't like the way they look.

I did some searching and found this clear filler:

http://www.mcfeelys.com/product/CPF-2530/CrystaLac-Wood-Grain-Filler#pr-header-CPF__2530

I have not tried it yet but I am planning on ordering some to experiment with it. Have no idea how it would work with oil but it may be worth a look.

Thanks Chris, I may give that a try. Do you wash coat first with shellac, or just use oil?
Thanks Robert, I will check that out, looks interesting.

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Damon Wack
https://www.facebook.com/LindamonGuitars

Coming more from the furniture world, I guess I look at it differently. The old school way would be to rub it with some boiled linseed oil (etc) and pumice until the pores are filled with a slurry of oil, pumice and wood dust. This is much faster and easier than pumice/shellac. More oil will seep into the wood of course, but since this is a resonator it shouldn't matter much. The figure will pop much more than with shellac/pumice.

You can also simply wet sand the bare wood using oil as a lube. Similar results.

The LMI 'natural' micro-bead seems like it would be way too light. Walnut/rosewood would be better. You can always tint it with acrylic colors.

Don't fill with anything other than the oil finish as a slurry fill, using the oil and sanding dust and pumice. That is if Tru Oil is considered a oil finish.. Then French polish the rest in light coats.

Just be mindful that these oil slurry fills will shrink back. They don't get as hard as something like Shellac and Pumice and they take longer to truly dry. I'm not saying that they are a bad idea. In many ways an oil slurry gives a very good match to the wood because the oil tends to darken the slurry.

IMO the pores are part of a natural finish. Here's a Koa guitar with Arm-R-Seal wipe on oil and urethane finish, five coats IIRC. The Sutherland Welles products look interesting too. I'm thinking of trying those at some point. It has some paste wax finish, too.

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Ken Franklin
clumsy yet persistent
https://www.kenfranklinukulele.com

For what it may be worth, I use Watco Danish oil as instructed on the can. Leave it three days and continue with your finishing. The Danish oil brings out the grain in mahogany (I can't afford koa). I finish with wipe-on poly (satin). Truoil may work by itself.

Bob

I love this type of look. Paste wax really adds to an oil finish. I love how they feel.

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Guitars, guitars and more guitars.

Are you saying you use Danish oil as a pore filler?

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Formerly known as Adaboy.......

You can use danish oil as a filler using the sandpaper slurry technique. Trying to fill pores with Danish Oil alone is likely to take a few months. Of course you don't have to fill pores and if that is the case it's better to aim for a satin or dull finish IMO.

Ken, that's beautiful! What kind of paste wax do you like?

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Damon Wack
https://www.facebook.com/LindamonGuitars

I was given some as a gift years ago by a very nice English lady. Don't know if it's available anywhere now. No brand name on the can. Just says paste wax finish as used on furniture in the National Trust. It's so old I have to add a little walnut oil so I can apply it. I've found that it doesn't take much but the surface of the oil finish has to be good for it to look smooth and even. The ticket with that is to use the oil-less superfine steel wool like Liberon (LMI) before the final coat and apply the final coat by quickly removing all the oil before it has a chance to get tacky.

I used the same finish on some mahogany recently.

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Ken Franklin
clumsy yet persistent
https://www.kenfranklinukulele.com

Briwax is a good brand for this type of thing. It dries quickly and hazy but after you wipe off the excess and buff it looks great. I have found other brands take to long to dry....Mike

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Guitars, guitars and more guitars.

Thanks Ken, I really like that look, I will try it. Looks like you use the semi-gloss, correct?

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Damon Wack
https://www.facebook.com/LindamonGuitars

Semi-gloss is good because the pores don't shine so much as gloss. Satin is a little too dull overall. I actually like somewhere in between and mix the semi-gloss with the satin but if you're just buying one I'd get the semi-gloss.

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Ken Franklin
clumsy yet persistent
https://www.kenfranklinukulele.com

Hi Ken, your Arm-R-Seal finish looks great and has me very intrigued. Not having done this type of finish before
can you post your process and finishing schedule?
Thanks

Ken, how hard is the Arm-R-Seal oil and urethane finish after it cures? It sure looks nice.

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Formerly known as Adaboy.......

Thanks, jfitz. I only use this on the neck and body, not the top. It's a pretty forgiving finish to apply. So if you do something you don't like you can just do another coat. Here's what I do.

Sand through the grits to 400. Since you are using this as a penetrating finish and not a film finish the prep is more important as scratches will show up more.

Apply with a folded paper towel or cloth in a thin coat and rub it in as you go. I don't like to leave much on the surface, but if you rub too much it can start to grab so just move on.

Let it dry for at least 24 hours. It might take longer in high humidity, cold weather or on certain woods. But it must be dry before you add more coats. On some oily woods it may not work well. I've had trouble with ebony. There are two things you can do for stubborn woods, do a couple of thin coats of shellac first or wipe off any finish that won't dry. I have had more luck with wiping off uncured finish because it retains the look I'm going for. There will still be some finish on the ebony and ebony doesn't need much protection.

Then I do two more coats letting each dry first before applying the next.

Then I sand lightly with 400 grit gold paper. I don't wet sand because I don't want to clog the pores.

Three more coats.

Sand with 400 paper. Then rub with Liberon 0000 steel wool (LMI). It is finer than most hardware store 0000 steel wool and it doesn't have any oil in it. You should cut a chunk off of the roll rather than tearing it.

Then for my final coat I try to apply very little quickly and evenly. If you do any rubbing with steel wool after this the little scratches can show or the finish can look uneven. If it doesn't look even enough for you just steel wool it and do it again.

When it's dry apply a good quality paste wax if you like, but it will be very hard to add more finish after that.

Hope this helps.

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Ken Franklin
clumsy yet persistent
https://www.kenfranklinukulele.com

I would say it's about as hard as french polish. The finish penetrates the surface of the wood and makes it tougher. It's not that hard, but dings don't show up as much as those on a film finish do. I don't use it for softwood tops which I think benefit from more protection, but I know of someone who did use it there too. For tops I use an oil varnish that has about the same sheen as the back and sides.

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Ken Franklin
clumsy yet persistent
https://www.kenfranklinukulele.com

Ken, thank you very much for posting your process. How long does it take for this finish
to fully cure and is it repairable? What oil varnish are you using for the top, are you using a sealer
underneath and how many oil varnish coats are you using?

For now I'm just using Ace varnish from the local hardware store. Six sprayed coats. I have put the Arm-R-Seal over the varnish before to keep the look the same but it isn't as tough.

The Arm-R-Seal will be cured enough to play in a week but it will continue to get tougher in a month or so. It's repairable if you don't use a wax over it. Since the finish is penetrating and not a glossy film it won't protect in the same manner that most are used to. It's a lot like Tru-Oil in that way only better. You get dings and scratches but they don't show up much like a gloss finish. More like the patina on an old piece of furniture. If you are willing to accept that then it's a great finish. It will never look like perfect lacquer but some of my customers who like it don't want the shiny look.

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Ken Franklin
clumsy yet persistent
https://www.kenfranklinukulele.com