Madder Alum Rosinate


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3 hours ago, Davide Sora said:
I share your perplexity, I have enough experience to know that the same varnish applied differently, with different dilutions, different thicknesses of the layers, different drying times between layers and all others possible variables in the application process can give very different results, from the perfect varnish to the worst aligatoring.
So it is difficult to make absolute claims based only on a couple of cases, even if reported by reliable and experienced people.
 
Having said that, also in my opinion it is not a good idea to follow Michelman's book to the letter, but the basic ideas are not to be thrown away.
I also suspect that the causes of the bad alligatoring  can be found otherwise, for example if the impregnation with oil suggested by the book was used as a ground, it could be this to have caused problems and not the varnish itself, or insufficient drying time between layers or a too thick layer or......or.....or......:rolleyes: 

What I wonder about Michelman is how this varnish dries, as the rosinate and drying oil are not fused. If you cook them together you get an extremely well drying varnish, I get a drying time of 3h in UVA.

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50 minutes ago, uguntde said:

What I wonder about Michelman is how this varnish dries, as the rosinate and drying oil are not fused. If you cook them together you get an extremely well drying varnish, I get a drying time of 3h in UVA.

Fused or no, the oil continues to dry via polymerization and takes the resin with it. Different metal salts effect different drying rates upon the varnish, whether cold-solved or cooked.

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7 hours ago, Mike_Danielson said:

Don has recalled an important issue.  A number of years ago, John Masters revealed what time had done to the Michelman varnish.  It shrinks, cracks, falls off etc.  I think John lives in Cincinnati and saw first hand what age does to the varnish (and reported it on Maestronet).  Michelman lived in Cincinnati  and published his book in 1946; so plenty of time has gone by.  In other words, the Michelman varnish is unstable.

Is the Alizarin you are using really alizarin crimson (which is already a lake)?   

Why not look at the quinacrodones--they are very light resistant.  Since you are already getting away from what the Italian masters used, you might just as well look at a pigments which could never have been used by the masters since they were invented about 60 years ago.

Mike D

Mike, hopefully you have noticed that most of the discussion in this topic relates to using Michaelman rosinates in a cooked varnish, rather than using Michaelman's own cold-solved technique. These produce very different results. We have a number of makers in this thread that have had successes with both over a period of decades. It appears that some skepticism regarding the cold-solved variant is merited, but evidently it is not guaranteed to fail.

The alizarin I use is 1,2-dihydroxyanthraquinone from Sigma Aldritch. 

Historicity is not an endemic concern to the violin maker. In general it appears we all have areas of the work that we feel more or less conservative about. For myself, varnish is not one of those areas. On the other hand, I nail my necks and string with gut. 

I am large, I contain multitudes. 

 

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Jackson and others:  it is not possible to say how much effect the rosinates have on the instability of the Michelman varnish.  Maybe it is just due to the low temperature combination of oil + rosin, but the rosinates may also play a role--this remains unproven.  In other words, adding rosinates to a cooked varnish may also cause instability.

I remember a few years ago when Darnton was pushing his varnish which is a variation of the infamous megilp.   And just like todays discussion, there are true believers that make claims of success.  

The only thing you can "hang your hat on" are the recipes of Mrs. Merrifield.  A cooked oil + resin varnish, and she does not mean going to 120 degree C as adequate cooking.   

Is the reason you guys pursue this Michaelman varnish because you cannot make a cooked varnish like Hargrave details?  His recipe is very clear, but I appreciate that there are a lot of people that cannot make marinara sauce.

As I said in my previous post, since you are comfortable going going away from the masters' recipes, take a look at the quinacrodones since they are color fast.

Mike D

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57 minutes ago, Mike_Danielson said:

Jackson and others:  it is not possible to say how much effect the rosinates have on the instability of the Michelman varnish.  Maybe it is just due to the low temperature combination of oil + rosin, but the rosinates may also play a role--this remains unproven.  In other words, adding rosinates to a cooked varnish may also cause instability.

I remember a few years ago when Darnton was pushing his varnish which is a variation of the infamous megilp.   And just like todays discussion, there are true believers that make claims of success.  

The only thing you can "hang your hat on" are the recipes of Mrs. Merrifield.  A cooked oil + resin varnish, and she does not mean going to 120 degree C as adequate cooking.   

Is the reason you guys pursue this Michaelman varnish because you cannot make a cooked varnish like Hargrave details?  His recipe is very clear, but I appreciate that there are a lot of people that cannot make marinara sauce.

As I said in my previous post, since you are comfortable going going away from the masters' recipes, take a look at the quinacrodones since they are color fast.

Mike D

Mike, 

No need to be combative. I have made and used rosinate varnishes, Amber varnishes, copal varnishes, rosin varnishes, and Venice turpentine varnishes. They're all great and have their strenghts and shortcomings. I have no interest in convincing you or anyone else of the merits of any particular approach, but a great interest in sharing my experiences so that others can use it as they will.

Again, not interested in quinacrodones at present. Thanks anyway. 

 

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Application issues aside.  The Michelman method of varnish making and its modern variations...the best I have seen is from Frank Ravatin...tend to make strong colors with a distinct glassy appearance.  They will dry well if properly constructed.  They tend to thicken and become useless in a day or so due [I believe] to the high metal content.  Un-reacted metal salts can cause some surface issues like alligatoring.

on we go,

Joe

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Hi, if you have green vitriol, make up a hot solution of ivory soap (still fairly pure), take a hot solution of iron, with violent rapid stirring add it to the soap.  A waxy greenish precipitate will be on  surfaces, scrape off and warm dry. These are iron oleates , a very nice oil soluble violin red. Using artist pigments, umber, ochre, to produce colored rosinates is simpler.

 

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On 12/13/2018 at 2:50 AM, Mike_Danielson said:

Why not look at the quinacrodones--they are very light resistant.  Since you are already getting away from what the Italian masters used, you might just as well look at a pigments which could never have been used by the masters since they were invented about 60 years ago.

Mike D

You beat me to mentioning this important point, Mike. I'll get around to discussing my findings on modern pigments sometime in the near future. There is no reason to use historical pigments like madder and cochineal unless you are trying to reproduce something as it may have appeared in a Cremonese shop 300 years ago, but it must fade to what we see today if it is to be accurate. You are right about the quinacridones, but there are others too. I think we can do much better because we have superior materials and a deeper understanding of chemistry and optics.

Good point.

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