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BigFryMan

How to mix and measure varnish?

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Hi everyone,

When grounding/varnishing a violin, the quantities used for each coat are not large and the varnish precious. What tools do you use to mix up what you are going to use? Most measuring cups you could buy in a kitchen supply shop are too large. Are there specialty chemistry measuring/mixing tools that you use? 

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I use small one ounce plastic graduated measuring cups. They are marked fractionally in ml, ounces, drams and a few others and are disposable. Also if you have some extra mixed up varnish left over that you will use up in a few days you can put the cup in a zip lock bag and remove the air and it will keep ok. 

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1 minute ago, David Burgess said:

I proportion by weight.

I think everyone does. That was so confusing to me, seeing Roger's recipe for varnish with linseed oil in grams. But if you're doing ratios of oil and resin...yes. It's obvious, which is why I didn't understand. I just knew it wasn't a typo, and scratched my head for days. 

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For small quantities, a digital scale that reads .01g increments is most useful.  For transferring, I often use cheap plastic straws, even for solvents (the solvents will eat away the straw, but not immediately).  Plastic cups are OK for temporary use or if there's no solvent involved, but I mostly use small metal cups to hold and mix things.

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I Mix larger batches in jam jars, I don't measure much. I stir if I want more red, as pigments tend to settle after a while. 

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3 hours ago, not telling said:

I think everyone does. That was so confusing to me, seeing Roger's recipe for varnish with linseed oil in grams. But if you're doing ratios of oil and resin...yes. It's obvious, which is why I didn't understand. I just knew it wasn't a typo, and scratched my head for days. 

Weight gives more repeatable results, since various quantities of a dry resin will fit into a designated measuring space, depending on how lumpy or fine they are.

This can also reduce cleaning chores, compared with using using a separate vessel to measure liquids, only to pour it into another vessel. (And some will be left in the measuring container, so that's one more bugaboo on accuracy).  Everything can go into one container on the scale.

2 hours ago, pbelin said:

I Mix larger batches in jam jars, I don't measure much. I stir if I want more red, as pigments tend to settle after a while. 

Jam and jelly jars are good. And I often buy baby food just for the small jars. My wife likes the apple desserts much better than the squash puree, and they don't cost any more. :lol:

Another option is Vodka bottles. Even the plastic ones seem to be highly resistant to a host of solvents.

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I'm stubborn about exploring old ways. When it comes to varnish quantities I'm not at all claiming my practices have any virtue or advantage.  It just feels consistent and appropriate to me.  And for me, 'do as they did' and 'put yourself in their place' are just basics of my discovery process.

So, I don't 'measure' ingredients.  I mix my varnishes, colors, et al by rough proportions, eye, and past experience with the consistency (temper if you will) of mixtures.  

So, like the oldest recipes say, two parts of this, 3 parts of that, plus a 'bean' of the other thing. Etc.   

I cheat in several ways.  I use a thermometer when cooking volitiles. But only as a safety check.  I guide the actual work by silly old ways like, until a white smoke comes off, but not brown.

I also use a hot plate as my heat source.  And, while I do have a large collection of sea shells that I use to hold and mix things, I don't have the old clay mini pots.  I have instead and assortment of small modern white clay kitchen mix bowls.  Also little jars and lids scavenge from the kitchen discard.

For small quantities art work, I tend to look at over careful measuring as just a modern fetish. Though, on an industrial production scale I would agree with measuring and documenting every detail.  But for violin work, choices of actual materials and general balance of ingredients seem more directly to the point.   On the other hand, my 'do as they did' thing is also a fetish.

 

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43 minutes ago, David Beard said:

I also use a hot plate as my heat source.

 

If you are "stubborn about exploring old ways", that's interesting, since a hot plate will produce highly localized heating, and not anything close to the "surround" heating of a fire or an oven. likely used in the 17th century.

I would much rather produce a varnish which is reliable and repeatable, than try to convince a customer that they would do better from me continuously wallowing in,

"Geez, the eye of newt recipe turned out great five years ago. Can't figure out why it's been crap since then". :)

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Yeah.  I don't feel safe with coals or flame in my current space.  I will eventually change that.

I don't think the recipes are all that sensitive to the precise balance of ingredients, nor to the 'heating path'.

If you've driven off the volatile components, then you have.  If the varnish strings to a certain extent, then it does.

Notice also that almost all varnish recipes are given in measures that actually equate to very simple ratios.  So typically you see something like 4oz A, 4oz B, 1oz C, 2oz D.

Not only is such a recipe just as well expressed as 4A::4B::1C::2D, but also such a recipe suggests an insensitivity of the recipe to variations much less than the basic unit of the proportions.

If the balance was more sensitive, or had been discovered, formulated, or evolved to be actually sensitive to the balance of materials beyond say 1/4 of the proportions units, then it would be very unlikely to call for the materials in such a simple relationship.  If the balance of materials at the fineness of 1/4 the expressed proportions unit was actually significant to the character of the outcome, then something more complicated like 15A::17B::5C::8D would be more probable.

Since almost all the historical varnish recipes are expressed in very simple ratios, it indicates that either those recipes are wrong, or that empirically what mattered about those recipes wasn't very sensitive to the exact balance of materials. Not to the gross level of 1/4 the proportion unit, and certainly not to 1/100 the unit.

 

Good consistent and reliable results happen from learning and knowing the system you use.  Not really so much from the system you use.

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Some experiments are not worth precise measurements. Making wood stain is one example. Eyeballing in those cases suffices. However, controlling the rosin:oil ratio requires weighing as described above. Kitchen techniques using volumes invite inconsistencies, also explained above.  School chemistry classes covered that issue.

The way I measure liquids and powders is to "tare" or zero out with the empty glass jar on the scale. Then, I fill it. For ultra precise measurements I remeasure the jar to determine how much stuck to the sides. It's usually zilch. 

The digital scales are inexpensive and highly accurate as mentioned. I have 2. One is 0.01 accurate for small amounts and the other is 0.1 for large amounts. I have test weights to track their accuracy. So far they stay accurate because I store them  with nothing sitting on them. 

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I do understand that is now the norm. 

But, historical recipes and description, and the very simple proportions dictated in basically all older varnish recipes suggests that having 'twice' as much mastic versus rosin was a material difference to the old varnish makers, but having 1::1 versus .8::1.12 wasn't. 

While there is nothing wrong with precisely measuring your varnish ingredients, I think healthy it healthy to realize that measuring such ingredients precisely is no more consistent with historical varnish work than its would be to measure paints as you mix colors on a pallet.  There is a freedom to adjust granted by recognizing this.

Remember, when we prepare varnish we are mixing already complicated organic materials, and with oil and resin varnishes we are using heat to encourage and prepare crosslinking, but we are not running actual chemical bond reactions.  So the precise relationships that benefit clean and complete chemical reactions don't apply.

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True. If you were doing lab work, then the slight differences resulting from minor variations of actual quantities are worth noting.  And for large scale commercial operations, there may be cost benefits to such extra study.

But, it remains that historical varnish makers don't seem to have credited such small ranges of variation with any significance.  And for the efficiency of our own small scale explorations, that seems like a valuable bit of information to be aware of.

And even for the modern experimenter, those centuries of experience before the modern era suggest there's much more milage to be had from understanding larger changes of materia balance like 1::1 versus 1::2, 1::3, 1::4 or 1::8 than in spending much time on differnces like 1::1.6 versus 1::1.8.

 

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2 hours ago, David Beard said:

I do understand that is now the norm. 

But, historical recipes and description, and the very simple proportions dictated in basically all older varnish recipes suggests that having 'twice' as much mastic versus rosin was a material difference to the old varnish makers, but having 1::1 versus .8::1.12 wasn't.

Were these historical recipes by weight, or by volume?

"Balances" were readily available in Stradivari's time. There would have been no need for a ratio like 8:1.12, because one could more easily put the same block of wood on the other side of the balance which was used the last time the varnish turned out really well.

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On 8/2/2019 at 1:54 PM, David Burgess said:

If you are "stubborn about exploring old ways", that's interesting, since a hot plate will produce highly localized heating, and not anything close to the "surround" heating of a fire or an oven. likely used in the 17th century.

I would much rather produce a varnish which is reliable and repeatable, than try to convince a customer that they would do better from me continuously wallowing in,

"Geez, the eye of newt recipe turned out great five years ago. Can't figure out why it's been crap since then". :)

Because before you harvested the first eye, the newt's vision was 20/20.  Five years later and the remaining eye had been under significant strain, doing the work of two, contributing to a change in the second eye's ratio of fat to muscle.  Et voila!  (Or Bob's your uncle if you have an uncle named Bob).  Crap varnish.  :lol:

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I don't think most specify, especially earlier.  Later I think, you see 'by weight' here and there.

Yes, of course, they could have weighed things, and developed much more particular recipes.  The point is that when people did write down recipes for varnishes, the proportions are consistently very simple.  And very often no more specfic than 'parts'.

So the general impression is that they just weren't that particular with the exact quantities in their varnish work.  Just because that sort of precision became important to large scale manufactures is no reason for us to project back and assume that particular precision was important for earlier artisan/craftsman work.

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18 minutes ago, David Beard said:

I don't think most specify, especially earlier.  Later I think, you see 'by weight' here and there.

Yes, of course, they could have weighed things, and developed much more particular recipes.  The point is that when people did write down recipes for varnishes, the proportions are consistently very simple.  And very often no more specfic than 'parts'.

So the general impression is that they just weren't that particular with the exact quantities in their varnish work.  Just because that sort of precision became important to large scale manufactures is no reason for us to project back and assume that particular precision was important for earlier artisan/craftsman work.

What was their definition of "part" ? weight/volume?

As far as protecting back regarding precision...... pyramids, parthenon, anything Leonardo played his hands/mind to????.......

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I can't say I know, as usually unspecified.  Sometimes it seems to be volume, later more likely to be weight.

If you're putting equal parts of rice and barely into a recipe, does it have to be either by weight or by volume? Does it have to be exact or the recipe is ruined?

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24 minutes ago, Michael Jennings said:

What was their definition of "part" ? weight/volume?

As far as protecting back regarding precision...... pyramids, parthenon, anything Leonardo played his hands/mind to????.......

Are those meant to be examples of modern precision in ancient work?  If you check those out, I believe you will find they each illustrate just how much older notions of fine work differ from modern values of squareness, numeric measure, repeatability, and precision.

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5 hours ago, David Beard said:

 

But, it remains that historical varnish makers don't seem to have credited such small ranges of variation with any significance.  And for the efficiency of our own small scale explorations, that seems like a valuable bit of information to be aware of.

And for that reason there is poor consistency in those varnishes. 

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I use "brushloads" which will vary on the brush....but I do have specific one that I always use, so for me they are very accurate but somewhat arbitrary as far as it being "universal" form of measurement....

 

 

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2 hours ago, Michael_Molnar said:

And for that reason there is poor consistency in those varnishes. 

Look, I'm not saying there's any reason not to measure precisely if you want.  Just that it doesn't appear to likely matter so much.

Do you have any varnish recipes you use that are actually expressed in anything other than very simple ratios?

Do you believe that varnish recipes described in maybe a total of 12 parts of the whole began with a granulation of more like 1000 parts of the whole, and then through empirical testing zeroed in on the simpler proportions as THE necessary balance of ingredients that must not be deviated from?

If an assistant made one of your varnish recipes but varied the balance of ingredients by not more than 20% between any components, do you think it would: Ruin the batch?  Make a difference you would easily notice? Make a difference you could disern with careful testing? 

 

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6 hours ago, David Beard said:

Look, I'm not saying there's any reason not to measure precisely if you want.  Just that it doesn't appear to likely matter so much.

Do you have any varnish recipes you use that are actually expressed in anything other than very simple ratios?

Do you believe that varnish recipes described in maybe a total of 12 parts of the whole began with a granulation of more like 1000 parts of the whole, and then through empirical testing zeroed in on the simpler proportions as THE necessary balance of ingredients that must not be deviated from?

If an assistant made one of your varnish recipes but varied the balance of ingredients by not more than 20% between any components, do you think it would: Ruin the batch?  Make a difference you would easily notice? Make a difference you could disern with careful testing? 

 

Varying any ingredient by 20% will for sure change the properties of any varnish.

I think the OP was referring to the problem of measuring out a small amount of something and then losing the portion of it that won't come out of the measuring spoon. Measuring by weight in a single vessel eliminates some of that but could result in an ever expanding batch if one accidentally adds too much of something. 

With colors some times there is more left on the spatula than going into the varnish.

In application, as you say, there is a certain amount of "that looks about right" but when making the varnishes themselves weighing out the ingredients leads to the most controlable results. 

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