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I'm looking for opinions on whether or not to use Tung oil over grain filler on a african mahogany neck. I have someone who wants an un-laquered finsh on the neck using tung oil, but I typically use McFaddens Mahogany colored grain filler on my bodies and neck because I love the application of it and the shimmering looks. Is there anything that would cause me issues if using the tung oil over the grain filler?

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Barron Wesley Guitars

Understand that I have never done this before, but.......if you can shoot lacquer over it, I would think you could put Tung Oil over it. But if I were you, barring more experienced replies here, I'd get me a piece of mahogany and give it a try.
By the way, I gave your website a look. Nice looking guitars.

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Mike

The only thing nescessary for evil to thrive is for good men to do nothing.

I'm not very experienced with finishing supplies and pore-fillers, but I know one thing for sure... Tung oil penetrates the wood. That's what gives the feeling and the relief of the tung oil finish. I'd guess that pore-fillers or sealer could be a obstacle for the oil to penetrate. Even if you re-sand the porefill to the wood, it will stay in the pores ( ) and oil won't penetrates in those pore, maybe it could affect the finish. I'm sure somebody could confirm (or not) my toughts

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Francis Richer, Montréal
Les Guitares F&M Guitars

Hadn't thought of that. But I know that some people stain after pore filling, and stain penetrates the wood as well. Hopefully, someone who's done/tried to do this before will chime in soon.

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Mike

The only thing nescessary for evil to thrive is for good men to do nothing.

These two links seem to suggest it's common practice and will be fine.
http://home.howstuffworks.com/guide-to-furniture-finishes-ga6.htm
http://www.furnitureknowledge.com/how_to_refinish.htm

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Mike

The only thing nescessary for evil to thrive is for good men to do nothing.

I guess it would depend on the pore-filler you'll use. They're a lot. If you use epoxy, it will seal the wood for sure, so you better not put a oil finish. Maybe you should go with a oil-based pore-fill. In that case you can use tung oil over it. Not sure, but i think it could work with waterbased filler too. I know you can put tung oil finish over both water or oil based stain (i've just done that, water stain + TO), so it should be the same for porefills

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Francis Richer, Montréal
Les Guitares F&M Guitars

I wouldn't do it, primarily because of what Ti-Roux said - oils penetrate. I'd consider doing the oil first then the filler if the customer wanted it totally smooth.

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Bad decisions make for good stories.
-------John


My blog - http://poplarmechanics.blogspot.com/

Is african mahogany SO porous that you absolutly have to porefill it? From a personnal view, exept if pores are huge (like in oak or something like that), they don't bother me so much. I like the feeling and texture of the wood, and that's why i use tung oil finish: I WANT to keep this texture. anyway, you have to obey to the customer, but, if the neck was mine, i'd tell you: don't pore-fill it, sand it to 800. Couple coats of tung, sand it to 1000, couple coats, etc,etc, 'till 2000 and maybe more. Then polish it.

Again, only my 2 cents!

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Francis Richer, Montréal
Les Guitares F&M Guitars

Rather than use a pore filler, you could always wet sand the neck with the tung-oil to create a slurry that will somewhat fill the pores. Do enough coats using this trick and pores will be mostly filled with a bit of texture.

What do yu mean exactly? Put tung oil and and sand (with wet-sanding paper i guess) before it dries?

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Francis Richer, Montréal
Les Guitares F&M Guitars

That's exactly what he's saying. The gunk will fill up the pores, then dry and harden in there. Then you can smooth it all out with some fine-grit paper and steel wool. It'll feel like silk.

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Bad decisions make for good stories.
-------John


My blog - http://poplarmechanics.blogspot.com/

The Avenger has it right. It feels very ,very nice

Okay - thanks guys. So I posted this originally with this in mind:
I love the way the McFaddens Mahogany grain filler stains the mahogany and I wanted the body color stain from the filler to match the neck, but it turns out after doing some testing that just applying the tung oil to the neck without the filler actually matches pretty well to the color of the grain filler if it had been applied in the first place. So I should be able to get away with doing the filler on the rest of the body and leave the neck alone and just use the tung oil.

Thanks..

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Barron Wesley Guitars

Nice! I think i'll do it... would you do it for all grits? Or start this process at a certain grit? For final sanding I begin at 180 or 220 and go through 320 400 600 800 1200 2000.

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Francis Richer, Montréal
Les Guitares F&M Guitars

Okay, time for the ultimate lurker to chime in...

You have to determine if the "tung oil" you're using is actually tung oil, a wiping varnish, or a polymerized oil. Manufacturers absolutely do not call the finishing product what it is, nor do they divulge what's in them. You can do a simple test by putting a small puddle of the stuff in question on a non-porous surface (like glass). If it dries within a couple of hours, and is clear and hard, you have a wiping varnish that has trace amounts of SOME kind of oil (though not necessarily tung). If you have a polymerized oil, it will wrinkle up and still be soft. If you have true tung oil, it will not be dry at all, as it takes MONTHS for the stuff to cure.

If you're using a water-based pore fill (I believe McFadden's is waterbased), you can use the above finishes on top, BUT ONLY AFTER THE FILL HAS CURED! Doesn't matter what the can says, I usually wait around a week before throwing any finish on top of grain filler. When you apply the oil/varnish/whatever, you need to do a thinner coat first, then pore fill, then another thin coat, then you can start building your finish to flatten and buff. Unless you have true tung oil, which will not build at all.

Very hard to determine what you're playing with by looking at a name, label, or can. A good rule is that if it contains ANY thinner whatsoever, it's not true oil, as there's no need to thin oil.

Good luck, and may I suggest going to the library and checking out Bob Flexner's "Understanding Wood Finishing". That's what I did, and am I ever glad I did.