p. 59 of Hammerl varnish failure Options

[flamenco]

Hmm. What did I do wrong? P. 59 of "Violin Varnishes" gives

"boil 2 parts turpentine, 1 part Ventian turpentine, 1 part copal, 1 part sadarac in water bath until dissolved. Then add boiled linseed oil." Thinning with balsam turpentine.

I did fine up until adding the linseed oil, which gave me a wad of chewing gum and thin, clear liquid.

I'd like a nice double-boiler oilish varnish, but this wasn't it, at least not in the way I did it. Should I have let the stuff cool before adding the oil? Help.

Steve

[Michael Darnton]

I've seen recipes which used sandarac as an ingredient in oil varnish, but I've never met anyone who was able to do it--the usual results are a free-floating lump of chewy yuk such as you're describing. Basically, sandarac isn't soluble in oil or turpentine. There are ancient recipes for sandarac oil varnish, but the most credible explanation I've read is that juniper gum was also called by the name "sandarac", and that's what they meant to be used. I suspect the recipe you used is reprinted, but untested, and a bad one.

[flamenco]

That seems a credible explanation. I only used very small amounts as a test.

[andrew weinstein]

I believe sandarac can go into an oil varnish if you "run" it, which involves high heat, lots of smoke, and I feel is best left to the pros. I have done it , but think next time I'll try and get some from Gary Bease or Joe Robson. In that process, the thinner is added after cooling, as you wouldn't expose turpentine to high heat, at least not twice . It is always a concern when reading the old recipes if they mean what they say , and if what they called sandarac is what we call sandarac.
I know there are charts of what resins dissolve in what, and I believe it's usually a percentage. It sounds like the sandarac did dissolve in turp for you, as you said it was fine until you added the oil.Don't know if the oil was cold when you aded, I know some recipes call for adding warmed oil, don't know if this would make the difference in this case.
Andrew

[Michael Darnton]

I tried it by running it first, and got nowhere. I believe that Andrew Dipper's stated it's possible, but the amount he talked of getting to go into solution was so minimal that I wondered if something else wasn't actually going on--some minor component of the sandarac being dissolved. The charts I've seen completely deny the dissolvability of sandarac in turpentine. Most of the strategies I've seen involve the unwitting use of mutual solvents (that might be the case with using venetian turpentine, for instance, but only if you didn't cook the v.t. much in the process). Would you mind saying exactly what your recipe was?

[andrew weinstein]

It's been a while since I did this, so I'll try and find some notes, but the 2 basic ways were to heat the oil first and slowly add sandarac( and other resins if desired), which I had less success with, the second way being to run the resin and add heated oil to it, cooking until a drop of the hot mixture on glass pulls a long thread. Then, when cool enough, you can add thinner, though I believe Gary Bease is opposed to adding thinner. I assume then that he needs more oil than I tended to use. I was often using "venetian turp" with it, though then read that often what is sold as Ven. turp is actually rosin in turp., so who knows what I actually used. I should say that there was
some separation, so I can't say with certainty that all the sandarac went in, but it pretty much seemed to.
For any of you who haven't done anything like this and are tempted to try,please know that this is tremendously smoky and potentially a fire hazard, and in no way do I encourage you to mess with it. I have read that part of varnish making(cooking) success requires the batches to be of sufficient size, so I would endorse the idea of leaving it to the pros.

[Seth_Leigh]

Is there some attribute of sandarac that is sufficiently superior to other resins that do go into oil and turpentine fairly easily as to make it worth the hassle to try to brute force it? I'm just curious.

[Michael Darnton]

Harder is always better. Nothing worth doing is less than painful. At least that's the way I was taught restoration. :-)

Aside from that, there aren't too many traditional resins, and traditional recipes. People like to figure out old recipes, and there's an additional aura to the ones that don't seem to work well, that maybe if we figured out how to do them, THAT one would be the magic one. Amber was in that category for a long time--since it seemed impossible, from about 1800 to 1930 or so--a really active period in the effort to research traditional methods--to make it into a varnish, and it is rare, expensive, valuable, and has some interesting physical characteristics, it was a leading candidate for the Magic Varnish. Then someone figured it out, and since it was then available, it became the leading candidate to test, or if you're not into testing, to be uncritically swallowed whole. That luster still hasn't worn off, in spite of more recent research that leads in other directions.

[jeff1]

I know that alot of people thought Stradivari's success was in the varnish, I always felt the varnish plays an inportant part. But with as many test, and the scientific know how that we have today, I have never seen anyone agree on the varnish! Is there anyone that has come up with a recioe from their testing? Kremer sells an amber varnish, I don't know how good it is. Has anyone tried it?

[Michael Darnton]

Someone at one of the British museums did an analysis about 12 years ago. Walnut oil and pine resin were indicated--very simple, direct and historical. Of course as soon as that was published, the guy who was selling amber says their tests wouldn't have seen amber (which I have also heard is not true, so who knows). As long as someone's got an axe to grind, there will be grinding noises. :-)

I've seen some really beautiful modern varnishes, but I haven't seen any varnish that looks c1715 Cremona.

Personally, I don't think Cremonese varnish, per se, has anything to do with Cremonese tone--lots of Cremonese instruments don't have any remaining and they still sound special. That would seem to prove something...

[Seth_Leigh]

I know amber is the "fossilized" resin from trees, but is it a specific tree like pine, or can amber come from other trees as well? Would a test for 300 year old pine resin look chemically like amber?

[jeff1]

Mike, how long have you used your varnish recipe? How is the varnish holding up, as far the oldest violin that you used it on? Can you describe how the age is effecting it?

[Michael Darnton]

I started using in around 1995 or so. When I see the violins again, some of them haven't changed a bit. On others the varnish has rotted some, or developed a crackle in body contact spots. It's not a tough varnish, but it isn't just dropping off, if a player is careful. I, and others, have been real satisfied with the *way* it ages. It wears gently, and doesn't look harsh.

I'm not saying it's the best varnish I've ever seen. It's fine, and it's very easy to make and use. It's not "Cremonese". I'm more interested in what's under it, though--if there's a "secret", that's where it is, in the wood or the "undercoat", or whatever you want to call it.

Previously I was using a cooked varnish of damar and oil. It's about the same strength, but it ages differently--less attractively--it boils and bubbles and pops off all at once in contact areas, leaving the wood looking a bit naked.

[fiddlecollector]

Michael, is there any difference between your varnish and Michelman base varnish ?

[Matej_Kliman]

I want to make a point on the discussion that went here some time ago. With a friend we made some experiments with the varnish cooking and had some good results.

I am also very critical about the historic recipes, being fully aware, that we do not know if amber or sandarac was what we now call it.

Nevertheless we have managed to make a simple 100% sandarac-linnseed/wallnut oil varnish (no chewy yuk) and amber-sandarac-pine-linnseed/wallnut oil varnish being inspired by some of historical instructions. My point is that varnish cooking may be regarded as a kind of alchemy, which was based on repeating the unsuccesfull experiment in the hope of reaching the correct constelation (of stars and planets). Having the experience with these unsuccessfull experiments and being now able to succeed repeatedly, I incline to agree with the theories saying that most of the old recipes are possible, and that it realy depends (among other things) on the actual subtleties of the varnish-making proces. These subtleties might have been quite easy for an instrument maker to show them to his/her sons or daughters or pupils, but quite difficult to put into a recipe.

[David Tseng]

Varnish making is a chemistry and therefore, should be reproducible. Would you give us some hints about your successful process? I've never used sandarac myself.

[Matej_Kliman]

I am not at all saying that making varnish is alchemy! It is just a feeling I sometimes got when we were (with my friend) trying and retrying it. And I used it as an argument in reply to Michael Darntons partial dismissal of some old recipes which do not seem to work today (e.g. soluting sandarac in oil).
In fact I do not yet know if it was a succes because I never used Sandarac either. And I think I never saw a recipe using sandarac only. We produced very transparent lightly yellow varnish that seems to dry well, but that is all we know for now. We intend to use it for the top coats, following Mr. Darnton's suggestion, that the harder the better.
We simply cooked it and aded warm thicknessed combination of linnseed and wallnut oil (quite a lot, compared to other resins). After ading the oil, the varnish is soluble in turpentine.