Official Luthiers Forum!

Jim wrote: "What do you think about nail polish remover? (i.e., laquer thinner. Amazing what they can sell in cosmetics that draws attention at larger scale.)"

It's been my understanding that nail polish remover is acetone, which is a relatively benign solvent compared to what I think of as "lacquer thinner," the stuff you thin nitrocellulose lacquer with. Doing some research on the Internet, I see that nail polish remover could be different things. Wikipedia says of nail polish remover: "The most common remover is acetone. This can be harsh on skin and nails,[16] and can also remove artificial nails made of acrylic or cured gel. A less harsh nail polish remover is ethyl acetate, which often also contains isopropyl alcohol.[17] ...Acetonitrile has been used as a nail polish remover, but it is more toxic and potentially carcinogenic. It has been banned in the European Economic Area for use in cosmetics since 17 March 2000.[18]."

Nitrocellulose lacquer thinner is a mix of things, which can vary, and includes (or may include?) toluene, xylene, ketones, esters, glycol ethers and alcohols. I'm over my head on the chemistry of this type of lacquer thinner, and someone else more knowledgeable may step in. But it's clear that some of these can be highly toxic and most sources say should be used only with a suitable organic vapor respirator.

I try to stay away from nitrocellulose lacquer thinner but I'll use acetone from time to time. That isn't to say that acetone isn't "toxic" but toxicity is relative and, reading about the hazards and dosages, I'm willing to tolerate a bit of it. That's not to say anyone else should. I think most of us, including me, could probably benefit from doing more research on what we use and considering what risks we are willing to take and how we might reduce them.

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Tim Allen
"Never hurry, never rest."

As with most substances.... the poison is in the dosage.
Even water will kill you if you drink too much.

Didn't take me long to start using a respirator when shooting lacquer (after a shooting session, I'd be high as a kite, then endure a blazing headache on the way back to reality).

Stuart Mossman never learned, which is why he had to quit making his wonderful guitars.

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

Tru oil is pretty simple to apply, a plus point as far as I'm concerned. It's also 'oil', which means it displays wood grain to great effect. A good test is to take a test board of your favourite wood and divide it into two. Finish one half in shellac (or other finish) and the other half with some sort of oil or oil varnish. Oil always wins with me.
It will take a decade or two to harden in the bottle (according to my recent correspondence with B. Casey). Once opened it has a finite shelf life. You can extend that shelf life by storing the bottle on it's cap.

Couple of questions for those who have experience with Tru-Oil. Does it cure hard enough to provide significant protection for spruce tops, and can it be buffed to achieve a level of gloss similar to other oil finishes? It seems most who use it are content with a more satin appearance, but I see some reasonably glossy finishes achieved using other oil products.

The ease and simplicity of application of Tru-Oil is appealing to me but I'm interested to know whether it can offer the level of protection and appearance I'm after.

Charlie T - I'm by no means an expert with Tru-Oil, this is my first time using it. I've got a Western Red Cedar top on this one and the Tru-Oil seems to me like it is indeed going to be nice protective finish. I would guess that after it's hardened it could be sanded up to a high micro mesh and get a nice gloss. I've got a board going that I'm going to run a test on and see. The guitar I'm doing now doesn't want a mirror finish. I'll post photos here when I'm done.

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It can get pretty glossy if you put enough on and take it right up the polishing compounds. Nowhere near to satin. In fact I've done test pieces where I've polished it up to gloss after it's only been curing for one full day. Not advising that, just that I've done it. It looked a perfectly nice finish. Actually polishing out early can be a way of controlling the final effect of the finish. It will shrink back and take on the tiny contours of the wood. Otherwise if you want it flat flat allow it to harden and shrink back for a good month, then flatten/polish. You'll end up with a much flatter billiard ball finish. All depends what you like.
As for hardness/protection. Difficult to say. The problem with testing it on softwoods is that you are more likely to test the underlying wood rather than the finish. The more analytical method is to test it either on glass or on a very hard wood like ebony.
So far my tests seem to suggest that it's a touch softer than shellac but there really isn't a lot in it. It's not bomb proof and glass hard like the old rockhard used to be. Certainly good enough for fingerpickers and for those who treat their guitars well. Not so good for heavy strummers who get a little carried away.

Strong smell, or no smell, doesn't always equal toxic or non-toxic. WB finishes have little or no smell, but still have a level of toxicity. Every finish should be used with proper breathing protection.

Alex

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"Indecision is the key to flexibility" .... Bumper sticker

Patch and Michael - thanks very much for your replies. That is encouraging.


How many coats do you reckon would be enough?

Exactly right. If you read the MSDS sheets on both you'll find that the main difference is flammability. Waterborne is not flammable.

I don't know. I'm one of the very few who brushes it and I can put on 10 coats over 24 hours, thanks to a UV cabinet. In fact I've never heard of anyone else who does brush it on. I'm guessing that might be the equivalent of 20+ wipe on coats. You might have to put those 20 wipe on coats over the course of a week, perhaps 3 coats over a long day. There are people who have far more experience of applying it like that than I do. Must be plenty of information on it in the archives. If you sand to a high grit it will make your life a little easier and perhaps make things go a bit quicker. The action of French polishing helps fill any tiny voids, evens things out, fills in. Other varnishes do that to some extent as well. Tru oil is pretty thin though, so you might need to apply huge numbers of coats to fill those imperfections. It's just easier and faster to take the finish to something like 800G and to make sure you are removing any scratches. Any oil finish really highlights scratches if it's applied directly to the wood, probably because it darkens the grain, especially end grain. Shellac tends to fill them, doesn't darken them as much, doesn't highlight them. You can also put on a few wash coats of shellac prior to using the tru oil. I do that for the soundboard, using a very thin watery cut of shellac. I think it's probably under a 1 lb cut.

So here is the guitar I tried out Tru Oil on. I did 3 coats a day usually every other day 5 times, so about 15 coats. Before I did my last round of oil I let the guitar sit for 3 days to harden before sanding, I think I'll wait a bit longer next time.

What I like about the Tru Oil is that it didn't affect the burst color. I use StewMacs alcohol based dyes and in the past when using shellac it moves the color around, which is a bummer. I'm thinking maybe the alcohol in the shellac mix is what does this. When I've finished black stained furniture with Osmo oil it drags the color. The Tru oil didn't even pull any color on to the cream purfling or rosette.

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http://www.wideskyguitars.com
https://www.instagram.com/wide_sky_guitars/

Excellent! Has a lovely antique glow. Not too shiny.

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

Looks good. Very vintage.

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Steve Smith
"Music is what feelings sound like"

Very, very nice!

Alex

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"Indecision is the key to flexibility" .... Bumper sticker

Patch

Very nice looking guitar - what is the bracing on the top? How is the volume with the tailpiece? Is it an early Gibson L body?

Ed

That finish looks very nice, as does the guitar.
Bob

Thank you for the kind words!

Ed- This is a replica of the Gibson L1 that I've been making. I've been bracing this with an X pattern along with a brace that runs side to side on the lower bout to support the bridge. So kind of like an A, if that makes sense. Getting good volume and a full sound, I built the box a bit deeper mimicking the Nick Lucas era of the L1. They are a fun little guitar, I've made over a dozen of them so far and the interest seems to keep growing. Gregory Alan Isakov and Sean Hayes each have one. At the end of the month I'm sending one out for someone to try and if it does what they are looking for it'll be out on an arena tour starting in January. So, fingers crossed...

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http://www.wideskyguitars.com
https://www.instagram.com/wide_sky_guitars/

I've been using tru-oil since the seventies. Put super thin coats. The smell well it does go away. You should raise roses man you should smell some of the sxxt you put on them.


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