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Hi all,

I'm in the home stretch...getting ready to finish my first guitar. I think I have pretty much decided on how I want to finish this guitar, but have some questions about other finishes as well.

I'm heavily leaning toward using Tru-Oil, nostly for the simplicity and my lack of experience in finishing. From what I've read, it can give a good looking finish with minimal risk.

I have seen, and read about, other finishes that look interesting. I don't know about their applicability to musical instruments, however, so thought I'd ask if anyone here can fill me in.

1. Minwax Wipe-On Poly




2. McFadden Gel Clear Topcoat




3. Deft
Brush-on Lacquer




What kind of finishes are these really (oils, varnishes, lacquers, etc.), and are they all suitable for guitars (bodies, tops)? I'm obviously very uneducated in this area, so I (and others, i'm sure) could use the education.

Cheers,
Mark

I'm not the experienced one here, but I don't think I'd use any of those listed except Tru-Oil. Another option, if you want a gloss finish, is Behlen's Rock Hard varnish. At least a couple of folks here are using the Behlen's, and are getting good results. Perhaps they'll chime in.

BTW, the Minwax Wipe-On Poly did get an outstanding review from a major woodworking magazine (I've forgotton which one) in a test of wipe-on varnishes. It costs less than most, and gave the best results. I don't know if anyone has tested it against the Rock Hard (which wasn't in the above test) to see if it's suitable for instruments.

Also, don't even open a can of that Deft lacquer indoors unless you're wearing a fume-approved respirator. Nasty stuff. You can probably guess how I know this.

I would encourage you to experiment with these finishes and see what you think of them. I don't believe there's anything magic about a finish for musical instruments. Anything that can be applied thinly, is reasonably durable (thinking in terms of the kind of handling and contact with sweat and the like that guitars are subject to), and gives you a look you like is a fine candidate. Polyurethane varnish in a wipe-on form could certainly fit the bill (I'm not familiar with the Deft, so I don't know what exactly that one is). I've used the McFadden's clear gel satin poly on one guitar and liked it a lot -- though it was not without its challenges, and no finish will be challenge-free. I may well use it again. Everyone will have different opinions -- I'm one whose opinion of nitrocellulose lacquer is not very high, and I'd use many other things before I'd even consider that stuff, but, obviously, a lot of people think nitro's the cat's pajamas.

Tru-oil may be a fine option for you, but I wouldn't turn your back prematurely on other options. I've seen beautiful Tru-oil finishes on instruments, but a lot of it has to do with the skill of application, and a wipe-on poly can also be very beautiful (and would be more durable than Tru-oil -- I think most would agree with that statement).Todd Rose38927.9348842593

_________________
Todd Rose
Ithaca, NY

https://www.dreamingrosesecobnb.com/todds-art-music

https://www.facebook.com/ToddRoseGuitars/

Have you thought about French Polish? The original wipe-on finish...vpelleri38928.4604050926

I have used the Deft product on a guitar. It is actually nitrocellulose
laquer according the the Deft rep. It really is pretty hard work (not to
mention the pain of having to use a high quality respiration filter the
whole time). It goes on pretty thick with a brush, and you have to do
quite a bit of sanding to get a flat surface (to eliminate brush strokes). I
feel like I was left with a finish that was too thick. I used it on my first
guitar. I have since built 4 more and used french polish on all of them.
French polish is time consuming and takes some skill. But my first guitar
with this method turned out fine, and the last three were pretty darn
good. The best thing is the sound transparency.

I will be removing the Deft finish from my first guitar as soon as I am
done with my current project and doing a french polish process. I could
use some advice on how to remove the Deft. Any takers?

Greg

[QUOTE=CarltonM] BTW, the Minwax Wipe-On Poly did get an outstanding review from a major woodworking magazine (I've forgotton which one) in a test of wipe-on varnishes. It costs less than most, and gave the best results. I don't know if anyone has tested it against the Rock Hard (which wasn't in the above test) to see if it's suitable for instruments.
[/QUOTE]

Is the Minwax Wipe-On poly actually a varnish (oil-based)? Is it suitable for sides/backs of a guitar? The labels tell almost nothing about what's in half these products.

I don't have personal experience with the Minwax, so I don't know about its usability on guitars. It is a varnish, but I don't know its ingredients. I can't find the magazine that had the varnish test, either. Sorry.

[QUOTE=CarltonM] I don't have personal experience with the Minwax, so I don't know about its usability on guitars. It is a varnish, but I don't know its ingredients. I can't find the magazine that had the varnish test, either. Sorry.[/QUOTE]

I just called Minwax to ask about their Wipe-On Poly product. The individual I spoke with said it's an oil-based product, but is a polyurethane finish, and differs from Tung Oil in that the tung-oil is an oil. I'm confused. What is a polyurethane finish, and what does that mean when talking about oil-based finishes?

$50 screened pavilion tent from Wal-mart and 2 tarps to block the up and down wind sides off and a good respirator, your all set to spray in the great out doors

[QUOTE=ms960]   I just called Minwax to ask about their Wipe-On Poly product. The individual I spoke with said it's an oil-based product, but is a polyurethane finish, and differs from Tung Oil in that the tung-oil is an oil. I'm confused. What is a polyurethane finish, and what does that mean when talking about oil-based finishes? [/QUOTE]

Mark, I'm not sure there's really a short answer to your questions. I strongly recommend you do some reading to learn about finishes. A great place to start is the book Understanding Wood Finishes by Bob Flexner. It is widely available, so you'll find it quickly by googling.

Polyurethane (that term describes the resins in the finish) is perfectly appropriate for guitars. It can certainly make a beautiful and very durable finish, and, like just about any finish, can be varied a great deal by the method of application (as well as by the specific product used, e.g whether it has a flatting agent added to give it a satin sheen rather than high gloss). For example, if you wipe on a coat of shellac under it, or fill the pores with epoxy and leave a thin layer of that on the surface, etc, you will end up with different results. Experiment on scrap.

As long as your finish is very thin, there will not be any discernible difference between different finishes in terms of how they affect tone. I know some would disagree with that statement, but many agree. An advantage of wipe-on finishes is that they will produce a very thin finish, unless you spend hours and hours wiping on many many coats, but you wouldn't do that.   

_________________
Todd Rose
Ithaca, NY

https://www.dreamingrosesecobnb.com/todds-art-music

https://www.facebook.com/ToddRoseGuitars/

Todd,

I realize I'm probably making this more complicated than it needs to be. I will look for the book by Bob Flexner -- I feel like I'm bugging the good folks on this forum for information that I can get offline.

I guess most of my confusion stems from reading comments that say that furniture finish is not suitable for guitars, shrinkage or crackling in a finish, finish soaking in or not soaking in, etc. I am certain I didn't understand the context of most of those comments, but it's difficult with my knowledge of finishing to seperate the wheat from the chaff, so to speak.

Thanks for the additional information, and I will try not to pepper the forum with such basic questions that are better answered from other sources.

Regards,
Mark

Mark, I didn't mean to slam you for asking the questions, just trying to point you in a direction where you will learn what you need to know.

If your question was primarily about the issue of finish penetration... that is an interesting issue and one to pay some attention to. Finishes are often described as being either film finishes or penetrating finishes. As I see it, it's a bit of a false distinction. A lot of it just has to do with viscosity -- any finish that's runny enough, i.e. thinned with enough solvent, will penetrate. Pure oil finishes will tend to penetrate more even at thicker viscosities, if you flood the surface and let it sit on there a while before wiping it off. But even oil finishes, if they're "finishes" at all, i.e. oils that will cure, form a film on the surface.

You don't want a finish to penetrate very much on a guitar. So if you use a wipe-on finish that penetrates a lot, you want to wipe it off quickly so very little soaks in, then let that coat cure. You've now got a very thin film on the surface. Each succeeding coat will penetrate less because the surface is more and more sealed with the film you're building.

A bit of penetration can be a good thing. E.g. with an oil finish, that's part of how it pops the grain nicely and looks the way it does.

You can also reduce penetration of any finish by wiping on some shellac first. This will give a different look, but it can be an effective technique. Shellac goes on as thin as water, but because you don't flood the surface with it, and because the alcohol evaporates almost instantly, it doesn't tend to penetrate very much. And it seals the wood well.

A gel hardly penetrates at all, just because it is so viscous. I haven't used the Minwax wipe-on poly, but I doubt that over-penetration would be a concern with it.    If it seems to be a potential problem, you would just want to wipe it off quickly. Or, you could seal with shellac first. Shellac first on the bare wood might give you a nicer look - better color and better popping of grain. I found that to be very true with the McFadden's gel. Putting that stuff on bare rosewood didn't look good at all. Over a little bit of build of shellac, it looked great.

I hope this is helpful. I don't think you're making it "more complicated than it needs to be". The chemistry and behavior of finishes IS fairly complicated. But not so much that you can't get a grasp on a lot of it pretty quickly if you're hungry to learn and get some good books. Flexner's book, while not the last word on finishes, will give you a lot of very useful information and de-mystify the subject.

Good luck!

_________________
Todd Rose
Ithaca, NY

https://www.dreamingrosesecobnb.com/todds-art-music

https://www.facebook.com/ToddRoseGuitars/

Mark,

Minwax wipe on poly is a wiping or rubbing varnish. A varnish is basically made up of three ingredients: oil, (usually linseed), a resin(urethane), and mineral spirits. The ratios of the ingredients is what the makers market under different brand names. A wipe on varnish has more mineral spirits in the mix which allows it to be brushed or wiped on. You could even make your own varnish by mixing the three ingredients I mentioned in proportions that are suitable for you.