Violin Varnish Finisher Needed for Archtop Guitar

[redir]

Originally Posted by Alan Carruth

I made one small batch of oil-resin varnish many years ago. I've still got some of the ingredients, and may make another one day. It was a pain in the neck, and didn't come out nearly as well as I'd have liked, so it's not a priority, for sure. It did give me some insight about varnish, though, which has been a help.

Mayer, in his 'Artist's Handbook' makes the point that it's very difficult to make cooked oil-resin varnishes in small batches ("...smaller than the usual 50-250 gallon batch...", p185) and get good quality control. It's something that's best left to the pros, like making alloy steel.

It's hard to beat the Murdoch's 'Ure-Alkyd 500' varnish as a guitar finish. The main issue I've had with it is getting it to cure over some tropical woods. UV light helps a lot with that, and time, of course.

Alan, do you use the hard sealer too?

[Alan Carruth]

So far I have not used the hard sealer on an instrument. Maybe that would help.

[Bruce Sexauer]

I thought I read this thread, but what is "the HARD sealer"?

[redir]

Originally Posted by Bruce Sexauer

I thought I read this thread, but what is "the HARD sealer"?

On the Murdocks website for the varnish they have a link to the hard sealer: http://www.sutherlandwelles.com/murd...rd-sealer.html

Interestingly they apparently also realize that luthiers have adopted their floor finishes for instruments and as such provide a finish schedule as a PDF for guitars. The first step after surface prep is to use the sealer.

To the PDF -> http://www.sutherlandwelles.com/inst...HardSealer.pdf

I've used shellac for a sealer, and for color, for just about every finish I use so I'm just wondering.

[Alan Carruth]

I used the hard sealer when I varnished my kitchen floor with Murdoch's. It's apparently a thinner version of the varnish with higher oil content. I try to minimize the oil on my guitars, as it tends to add to damping, and so have skipped that step. I have to wonder, though, if it would help with drying on some of the oily woods.

[redir]

That sounds like a test in the making.

Do you seal with anything? Like shellac for example? OR does the Murdock's not stick to shellac well?

[Bruce Sexauer]

The reasonI DON'T want the hardest finish possible is that it adds structure where I have already gone to great lengths to get the structure as close to ideal as possible.

[redir]

Yeah I know what you mean but I wonder if the terminology is sort of exaggerated. Is it really a 'hardener' or just some sort of sanding sealer. I guess there is only one way to find out. After the new year I should have a bit of time to make some test panels. I've been on the look out for a good varnish and my local Ace doesn't carry the right stuff.

[Alan Carruth]

As I think of it, it would make more sense if the hard sealer had more resin and less oil, giving 'fat over lean'. It's plausible that the hard sealer dries more reliably. I really need to get out some of that stuff and check it out on some wood samples.

I use shellac to seal the wood before I do any grain filling. After the filler is in I also put on a wash of shellac, to seal in any colors that might tend to bleed out. I then sand back to wood to apply the varnish.

One of the big advantages of oil varnish, and especially the Murdoch's, is that it has the 'right' refractive index, probably matching that of cellulose pretty closely. As a result light can go through the varnish and the layer of cellulose it's bonded to, and then reflects off the back surface of the cell wall. This gives the highest possible color saturation and chatoyance to the finish: the wood colors and grain figure just pop. Shellac has a different refractive index, not as close to that of wood, and a layer of shellac, no matter how thin, between the varnish and the wood looks 'veiled'. I saw this years ago when I sanded through the shellac seal coat under a varnish finish; the next coat of varnish looked a lot nicer where it was on bare wood than it did on the shellac sealer.

[runamuck]

Originally Posted by Alan Carruth

As a result light can go through the varnish and the layer of cellulose it's bonded to, and then reflects off the back surface of the cell wall. This gives the highest possible color saturation and chatoyance to the finish: the wood colors and grain figure just pop. Shellac has a different refractive index, not as close to that of wood, and a layer of shellac, no matter how thin, between the varnish and the wood looks 'veiled'.

This is interesting and very helpful.

Thank you.

[redir]

Yes definitely good to hear, thanks Alan. If you do ever run any tests let us know.

[Bruce Sexauer]

I use more than a wash coat of SealCoat, and I do not sand it back to wood. As long as there is a film of SealCoat (alcohol based and handles like shellac) I have no trouble at all with any varnish drying.

[Quickstep192]

Originally Posted by Bruce Sexauer

It’s on the shelf at Petaluma’s Tomasini Rex Ace Hardware, and they order it for me by the 4 quart case. I have ordered it several times since the first time I was told by a would be buyer that it could not be found. Others have also succeeded at getting it. When I get to work later today I will post its product number.

Bruce,

Is this the varnish from Ace? Do I correctly understand that you’re mixing this with the Murdoch’s? Would you share the mix ratio?

[Bruce Sexauer]

Whoops. I forgot about posting the picture. That’s what I get for speaking before I’ve had my coffee. Yes, that’s the stuff. Thank you for covering my lapse.

I am happy to share my finishing schedule with any who ask BY EMAIL. My address is in my website’s contact page. My website is linked below.

I have finished about 100 guitars with Ace exactly as it comes from the can, and the Murdoch blending is something I have been messing with for only about a year. I have done only one guitar with 100% Murdoch, and its finish seems harder than my ideal. Something around 50/50 seems about right. No blend has been trouble.

[jazzer44]

Originally Posted by Alan Carruth

There does not seem to be any tonal magic in violin varnish, despite the centuries of myth. Nobody knows what Strad et al actually used for sure. From time to time somebody claims the have found 'the secret': one guy recently did that every ten or fifteen years, and it was a different 'secret' every time, so you have to wonder. The best scientific evidence suggests that there are lots of things that can work on a violin, and that what matters most is what the first couple of coats do.

I have to disagree. The finish makes a HUGE impact on tone just like different brands of strings used. There are literally thousands of different violin varnish recipes in both spirit and oil. Once you know your ingredients and how they affect tone you can customize the sound/recipe to your liking.

For the curious, take 2 identical violins, coat one with a fine spirit varnish, and the other in plastic finish. See if you can hear the difference.