Violin Forum/Message Board

kubasa · Member Joined: 13 Sep 2007 Posts: 212

So somewhere on one of the forums out there I had read an explanation of what happens if oil varnish has too much/too little resin, or the oil or the solvent. Has anyone seen this or is able to explain how different proportions effect oil varnish properties?

The reason for my question is that I thinned out some varnish with turpentine because it had thickened up. I applied the varnish to a violin that I finished last year. I have played this violin for 1 year now but have noticed that the varnish tends to be soft and rubs/flakes away in contact areas (varnish touching my neck and varnish at either end of the neck). I have not had this issue before so I tend to wonder if I thinned it too much with turpentine but I could be wrong. This is what got me wondering about different ratios or proportions and their effects.

Thanks in advance -
James

kjb · Super Member Joined: 06 Feb 2013 Posts: 385

there are some extensive threads on MN on this, I will not be able to acess them for about 15 days, when I get back I will check in.

L P Reedy · Posted: Tue Jun 09, 2015 4:27 pm Post subject:

Just thinning should not cause problems. The fact that the varnish had thickened MAY be a real problem. Unless it thickened from losing solvent, it has done some of what is supposed to happen after it is applied.

Changing the ratio of oil to resin can have noticeable effects, depending in part on the particular resin used. For my resin, less oil than 50% (by weight) makes a brittle varnish. More oil (I don't know how much more) can make a varnish that is too soft and not protective enough.

kubasa · Member Joined: 13 Sep 2007 Posts: 212

Thanks for the replies. I did find some more info today but not exactly what I had remembered reading. However, LP - thanks for the explanation. That was a simple, straightforward example for me. I was getting hung-up on the turpentine part and in reality that is probably unrelated if I'm understanding this correctly. The varnish had thickened in the bottle that (I thought) was sealed tightly. I ended up throwing out the varnish after I finished with that instrument but I should have thrown it out BEFORE I varnished....

Dave Chandler · Posted: Wed Jun 10, 2015 5:28 pm Post subject:

Maybe a very light top coat of clear, and good, varnish is in order?
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Dave in the Blue Ridge
Southern Violin Association

"Success is the ability to go from one failure to the next with no loss of enthusiasm" Winston Churchill

"I took the road less travelled, and now I don't know where I am." Marco Polo

Michael Darnton · Posted: Sun Jun 21, 2015 10:14 am Post subject:

The main symptom of too much solvent is patchy coverage because there are not enough solids within the mix to cover the area it's spread over. As LP notes, when you add more oil or solids to the mix, rather than solvent (turpentine) the varnish quality shifts towards the quality of whatever is becoming greater in the mix. Oil makes varnish rubbery, and what more solids do depends on the specific solids that are added.

For instance, I believe, but am not sure, that the reason people have had trouble with my mastic/oil varnish is too much mastic, which melts at hand temperature, makes a soft varnish that softens more if you look at it too hard.
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kubasa · Member Joined: 13 Sep 2007 Posts: 212

Thanks Michael. I had no clue that mastic melts at hand temperature. Wow, that's low. I've never messed with it but I can see where the proportions would be extremely important with your recipe. I learn so much here. Thanks all!

James

John Masters · Junior Member Joined: 13 Mar 2013 Posts: 23

kubasa · Member Joined: 13 Sep 2007 Posts: 212

Once again, I've learned something new. I never associated masticate with mastic. Makes sense though!

Dave Chandler · Posted: Wed Jul 15, 2015 7:50 pm Post subject:

Out on a lark today, I decided to see how long and how hard it is to collect enough balsam resin to make a dab of varnish. It took an hour to collect about a half ounce. I diluted it with alcohol about 2:1 so that I could strain the wood pieces out. Then poured it through a little cheese cloth, into a small metal container (small cat food tins are worth saving for projects like this). I heated it on my hotplate, and burned off all the alcohol. I let it cook for a bit, then added linseed oil - more oil than resin somewhat. Cooked it for quite a while on high heat, until it started to take on quite a bit of color, getting pretty dark. I never could get a consistency that when pressed between fingers and then seperated would make a gossamer thread longer than 1/4 inch. But if I cooked it longer, it would be black. Anyway, I diluted it 1:1 with mineral spirits, and gave one of my old fiddles a coat of this clear new varnish.

So question -- what constitutes a "volatile balsam varnish" and what are its constituent parts? What differentiates this from a spirit varnish? I missed "varnish 101".

Next question -- I've been using "boiled linseed oil" perhaps I should be looking for something else to mix my varnish, or is this OK? Maybe I should buy the artist quality at the hobby shop instead of this bulk stuff at the Home Depot.
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Dave in the Blue Ridge
Southern Violin Association

"Success is the ability to go from one failure to the next with no loss of enthusiasm" Winston Churchill

"I took the road less travelled, and now I don't know where I am." Marco Polo

DonLeister · Posted: Wed Jul 15, 2015 10:58 pm Post subject:

Yea, use artist quality, at least to eliminate that variable.

DonLeister · Posted: Wed Jul 15, 2015 11:00 pm Post subject:

By balsam varnish you mean exactly what... ? Species of tree is really important.

Dave Chandler · Posted: Thu Jul 16, 2015 3:14 pm Post subject:

We have a combination of Frazer and Balsam Fir in the forests above my home here in North Carolina. Abies balsamea. Red Spruce occupies the region from about 4800' to 5400' elevations, then above that it becomes a mix up to the 6000' range, then above that is the frazer and balsams. Its very hard to differentiate between the two, being nearly identical. These have the blisters in the bark from which you can get a drop or two of sap. Sometimes you can find a tree with 10-15 blisters, some only one or two. Great smelling stuff, like Christmas tree in a bottle.
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Dave in the Blue Ridge
Southern Violin Association

"Success is the ability to go from one failure to the next with no loss of enthusiasm" Winston Churchill

"I took the road less travelled, and now I don't know where I am." Marco Polo

Dave Chandler · Posted: Thu Jul 16, 2015 3:23 pm Post subject:

Fraser fir has a somewhat restricted range. It grows naturally only at elevations above 4,500 feet in the Southern Appalachian Mountains from southwest Virginia, through western North Carolina, and into eastern Tennessee. A number of stands occur in the Great Smoky Mountains National Park. Its highest native habitat is Mt. Mitchell, North Carolina (6,684 feet) which is the highest U.S. point east of the Mississippi River. A variety of balsam fir, phanerolepis, occurs in the Northeast United States and Canada and as far south as West Virginia and Virginia (38 degees north latitude). This variety is best described as an intermediate form between balsam fir and Fraser fir and may represent a remnant of a once continuous range of the two species.

Source:
http://www.realchristmastrees.org
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Dave in the Blue Ridge
Southern Violin Association

"Success is the ability to go from one failure to the next with no loss of enthusiasm" Winston Churchill

"I took the road less travelled, and now I don't know where I am." Marco Polo

DonLeister · Posted: Thu Jul 16, 2015 10:38 pm Post subject:

I know what you are talking about at least with the balsam. I think the resin is also called canada balsam. I have collected some of it when I visit in Maine, takes forever. I have about a cup of it and I just know that if I cook it down it will probably amount to about a quarter of that. But I have it if I need it!