Acoustic guitar Finishing advice

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Bob Orr
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Re: Acoustic guitar Finishing advice

Post by Bob Orr »

Jonathan Cressman wrote:
Wed Dec 16, 2020 6:44 pm
Thanks everybody for all the advice!

As Barry said, my neck is mahogany, and so needs to have grain filled somehow. Now, when I've looked around, I've found a number of people who seem to think that tru oil does a decent job of filling grain itself, and they don't seem to use a separate grain filler.

Any thoughts on using tru-oil by itself vs using a grain filler underneath it for a mahogony neck?

Think it would take an awful lot of coats. I use Z poxy as a grain filler under my Tru OIl finish. Robbie O'Brian has an video on his YouTube channel.

Bob Orr
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Re: Acoustic guitar Finishing advice

Post by Bob Orr »

Jonathan Cressman wrote:
Wed Dec 16, 2020 6:44 pm
Thanks everybody for all the advice!

As Barry said, my neck is mahogany, and so needs to have grain filled somehow. Now, when I've looked around, I've found a number of people who seem to think that tru oil does a decent job of filling grain itself, and they don't seem to use a separate grain filler.

Any thoughts on using tru-oil by itself vs using a grain filler underneath it for a mahogony neck?

Think it would take an awful lot of coats. I use Z poxy as a grain filler under my Tru OIl finish. Robbie O'Brian has an video on his YouTube channel.

Bob Orr
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Re: Acoustic guitar Finishing advice

Post by Bob Orr »

I use Zpoxy as a grain filler under Tru Oil. Robbie O'Brien has a tutorial on his YouTube channel

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Barry Daniels
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Re: Acoustic guitar Finishing advice

Post by Barry Daniels »

Hey Bob, what do you use as a grain filler under Tru Oil? ;)
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Bob Orr
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Re: Acoustic guitar Finishing advice

Post by Bob Orr »

Barry Daniels wrote:
Thu Dec 17, 2020 6:34 pm
Hey Bob, what do you use as a grain filler under Tru Oil? ;)

I use Zpoxy as a grain filler under Tru Oil. Robbie O'Brien has a tutorial on his YouTube channel

Bob Orr
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Re: Acoustic guitar Finishing advice

Post by Bob Orr »

Oops I've done it again! Didn't realise I had posted twice already!

Jonathan Cressman
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Re: Acoustic guitar Finishing advice

Post by Jonathan Cressman »

Hi all,

I was away from the guitar for a bit, but just got back into it, and applied my first coat of tru oil tonight. I had prepped all my wood by sanding to 220, and using pore filler on my mahogany neck.

To apply the tru oil, I had a rag bunched up into a tight pad (I think it's called a mouse?), would get some oil on it, and then rub fairly vigorously in circles. I also tried, in some areas, simply wetting a rag with the oil and wiping it on. I found both of these techniques worked well on my cherry back and sides, but when I got to my cedar top it did not apply well at all. With a freshly wetted rag, the first area I would touch would soak up a lot of the oil, but then It would stick there, and I wouldn't be able to spread it around like I had been able to on the cherry. I found I had to go to the bottle to wet my rag very frequently to get any kind of uniformity (which I think is bad, because everything I've heard suggests thin coats are best), and still, it came out quite blotchy. On my mahogany neck it applied quite nicely.

A couple questions:
1. Does anyone have any ideas why the finish came out blotchy on the cedar (not spreading as well as on the cherry and mahogany), and any ideas on how to improve this?
2. As stated, this was my first coat. The blotchiness has gotten definitely gotten better on the top as it dries, but is still somewhat noticeable. Might this even out as I apply more coats, or should I sand back to bare wood before trying again?
3. To wet my rag, I was simply holding the bottle to the rag, and quickly flipping it upside down. I found that I had to do this quite often (I would estimate I did it maybe 10 times for the back). Now, I know that thin coats are better, so I'm worried this is resulting in too thick an application. Anyone know if that is too thick, or fairly normal? Or does anyone have a benchmark/thing I can look for to know if I am applying it too thick?

Thanks!

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Barry Daniels
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Re: Acoustic guitar Finishing advice

Post by Barry Daniels »

The cedar is very adsorptive at first and soaks up the finish from the rag quickly. It will even out and get better as you apply more coats. Don't over sand it, just apply more thin coats. The top will be sealed by the 2nd or 3rd coat then things will go more smoothly.
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Jonathan Cressman
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Re: Acoustic guitar Finishing advice

Post by Jonathan Cressman »

Hi Barry, I've applied another 2 coats today, and you were right, the cedar is looking much better. Thank you!
A couple other questions:
What's a rough number of coats you typically like to apply? And, when I'm done with the finishing, is there a certain amount of time I should wait before stringing it up and playing it, or can I do that as soon as it's dry to the touch?

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Barry Daniels
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Re: Acoustic guitar Finishing advice

Post by Barry Daniels »

I suggest you apply coats until you are happy with the results. If you want a full build that can be polished to a high gloss with no low spots, you may need to do a couple of dozen coats.

You should let it dry for a few days before you start handling it.
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Alan Carruth
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Re: Acoustic guitar Finishing advice

Post by Alan Carruth »

'How many coats' is a hard one to answer in general. It depends on three things mostly; the finish you're using, what result are your after, and how good your surface prep is.

Tru-oil builds slowly so you will need more coats to get the same result. On the plus side, you don't have to wait too long in between coats, and they're quick to put on. Don't rush it, though: I'd be prone to treat this as a 'varnish' finish, and not put the next coat on until the last one is 'dust' dry when you sand it. I admit I don't have much experience with it, but it does dry like a varnish, by chemical reaction with the oil, and I would fear that building too fast could end up gummy because the air would have trouble getting through. OTOH, given how fast that stuff hardens up in the bottle (there's a reason the bottles are so small...) maybe that's unfounded.

The 'show' standard of finish is that when a fly tries to land on your guitar he skids off and breaks his leg in the fall. You might never get that with Tru-oil, but with enough coats you might get close. Most folks like that finish for the 'satin' look and feel. I'm not sure how well that stuff works to prevent water from getting into the wood, but once you have enough on the surface to do that, you're good as far as the 'need' for finish goes. That might only take a few coats. So it's anywhere between there and the 'show' finish. I will say that, if it's like most finishes, the more caots you get on the better it looks, so it can be hard to stop.

Surface prep is the biggie, though. Although I don't think you need to sand any finer than #200 grit on wood, you do have to spend the time to get things really level and fair. This becomes more imperative the more you intend to approach the 'show' finish. As Dante had Virgil say in the 'Inferno': "The closer a thing is to perfection the more it feels of pleasure or pain". Those little bumps really show in a gloss finish, and since a good finish is only a few thousandths of an inch thick, you can cut through fast if you're trying to sand them out after you start applying it. A little OCD in surface prep is a good thing.

Jonathan Cressman
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Re: Acoustic guitar Finishing advice

Post by Jonathan Cressman »

Thank for all the help everyone!

I've got 7 coats on now, and am already pretty happy with how it looks, so I think I'll just apply a couple more (I'll probably stop at around 10 coats).

It's already quite glossy - I don't think I really want it much glossier than it already is - so I think I will avoid buffing, and just leave my final coat as it is when I get there (buffing/polishing is for purely aesthetic reasons, correct?)
And it sounds like if I'm not planning to buff it, a smaller number of coats (around 10, like I mentioned) should be fine then?

Jonathan Cressman
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Re: Acoustic guitar Finishing advice

Post by Jonathan Cressman »

I'm all done now!
Thanks so much to everyone who gave me advice - it was super helpful, and I really appreciate it!
Here are some pictures of the finished product :)
IMG_4984.JPG
IMG_4980.JPG
IMG_4982.JPG
IMG_4988.JPG

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Barry Daniels
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Re: Acoustic guitar Finishing advice

Post by Barry Daniels »

Looks great!
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Bob Ionta
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Re: Acoustic guitar Finishing advice

Post by Bob Ionta »

Beautiful! Nice inlays. And that's your first build? Amazing. I was at the limit of my skills just getting binding on my first (and 2nd and 3rd), with no thoughts of fancy inlays. Very nice job. Enjoy playing it!

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Karl Wicklund
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Re: Acoustic guitar Finishing advice

Post by Karl Wicklund »

Nice work. I love that silky finish.
Kaptain Karl

Bob Orr
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Re: Acoustic guitar Finishing advice

Post by Bob Orr »

Lovely work and like how the head inlay goes down the fingerboard. Lovely clean work. I am with you on the finish, I like wood to look like wood. Not a fan of the high gloss factory look finish though I know a lot of people like it and some customers expect it. Different strokes!

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