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Juarnerius

Varnishing with diy lake pigments

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Hallo everybody

 

So i've been working on making my own oil varnish and pigments for a while now, and it seems that for every variable that i try at least 2 more open up. While looking for answers to different questions i came across several threads here that had a lot of useful information, but i couldn't find a lot about the actual method of grinding self made pigments into oil varnish, or how to layer them. Is somebody here familiar with these techniques and feeling like talking about them? I could really use some tips / tricks / things to avoid / things to look for from experienced people

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If it's DIY pigments, first you have to grind them fine. Mortar and pestle is very efficient for that. It's not possible to grind too much. Then when it's as fine as you can get it, put some oil or varnish on a piece of glass, and mix them. At this point, you can hardly mix too much, and you will probably discover that you didn't grind as much as you thought you did!

The best grinding I ever did, I got a rock tumbler, loaded it with pigment, marbles, and water, and let it go for three weeks. It was so fine it wouldn't drop out, and I had to dry it, then break that up.

Note that there's a difference between grinding, which is what you do to DIY pigments, and breaking up and mixing caked pigments, which is how they come commercially. Either one is a lot of work, and a lot of time. There's a reason the Renaissance painters had 13 year old kids doing this.

I'm agnostic on mortar and pestle vs spatula on glass, vs muller on ground glass--they all have their own advantage. Mullers get a lot of press, but they really aren't for grinding, they're for mixing, and a spatula does that job fine. The reason you should grind with a m/p is because the large area under a muller means each particle gets very little pressure, whereas the localized small area of high pressure of the m/p is more effective at grinding things small.

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Michael, thank you very much for your response.

I had seen the tumbler that you talk about, i thought it's way cool (but probably out of my budget) and it shows how fine you can get a pigment with it. Anyway i have always had a soft spot for the manual old school way of doing things, at least as much as i can make it viable

So far i prepared several "samples" until i got one that was not bad. I exaggerated the ammount of pigment on the varnish for let's say "scientific" reasons, and though it did end up less opaque than what i thought it would, if you look really closely you can actually see the red particles. So from what you tell me i should keep at it with the mortar some more before mixing no?

Also, while maulling i found out that my pestle (bought from Kremer at the last Mondomusica) has a slight hump on the centre of the flat surface, which considerably reduces the contact between surfaces. Do you think i can solve that with sanding on a perfectly flat surface?

 

 

 

IMG_2668s.jpg

IMG_2661s.jpg

Edited by Juarnerius
I resized the uploaded pictures

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16 hours ago, Michael Darnton said:

If it's DIY pigments, first you have to grind them fine. Mortar and pestle is very efficient for that. It's not possible to grind too much. Then when it's as fine as you can get it, put some oil or varnish on a piece of glass, and mix them. At this point, you can hardly mix too much, and you will probably discover that you didn't grind as much as you thought you did!

The best grinding I ever did, I got a rock tumbler, loaded it with pigment, marbles, and water, and let it go for three weeks. It was so fine it wouldn't drop out, and I had to dry it, then break that up.

Note that there's a difference between grinding, which is what you do to DIY pigments, and breaking up and mixing caked pigments, which is how they come commercially. Either one is a lot of work, and a lot of time. There's a reason the Renaissance painters had 13 year old kids doing this.

I'm agnostic on mortar and pestle vs spatula on glass, vs muller on ground glass--they all have their own advantage. Mullers get a lot of press, but they really aren't for grinding, they're for mixing, and a spatula does that job fine. The reason you should grind with a m/p is because the large area under a muller means each particle gets very little pressure, whereas the localized small area of high pressure of the m/p is more effective at grinding things small.

I could never understand why it necessary to dry lake pigments. This just creates labor of grinding them later on. I keep them wet and drive the water out with oil. Saves a lot of time and makes a wonderful homogeneous color paste. 

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15 minutes ago, Andreas Preuss said:

I keep them wet and drive the water out with oil.

That is very intriguing to read. Do you mean that you mix the wet pigments with oil and then the water separates like when you are washing the oil?

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Andreus, can you say some more about how you drive the water out with oil?   I also like the small particle size of "never dried" lake pigments.  But have not, yet, successfully incorporated them into oil varnish without drying first.

Mike

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I use a small muller -- about 2" across -- and find I waste less pigment.  But maybe that's an illusion.  I just find I spend less time scraping everything back up into a pile for further mulling since I tend to make small batches.

I also use a coffee grinder starting out -- I cheat? -- to start out with a finer consistency, reducing the time.

I have mixed turps or alcohol with the pigment as it comes off the filter -- turps for oil varnish, alcohol for spirit --, I get a "mud" which stays wet in a sealed jar for quite a while.  Sounds a little like what Michael does, though the oil instead of the turps may make a difference.  But my perception is that the mud results in a varnish that is too opaque.  I have assumed that is because the particles are too small to allow for the transit of light to the wood and back out again.  

Would love more information from the more experienced here.

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In grad. school we had a ball mill and a pigment grinder. The ball mill could be used wet or dry and we used to let it run over the weekend. The pigment grinder had to be used wet and you had to monitor it. The grad. art department painters would re-grind and reconstitute antique oil paints which were no longer made. I used to use it with cochineal and it worked well for me.

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11 hours ago, Julian Cossmann Cooke said:

I also use a coffee grinder starting out -- I cheat?

I think that could hardly count as "cheating". Unless someone is willing to argue that cutting out a neck with a bandsaw is cheating, or bending sides with an electric device.

 

9 hours ago, Michael_Molnar said:

I use dowels to roll inside a small jar

That is a very nice idea, keeps it all clean and gathered. Thanks for sharing!

 

4 hours ago, Fossil Ledges said:

The grad. art department painters would re-grind and reconstitute antique oil paints which were no longer made

Wow that sounds pretty badass. Oil painting has always been a platonic love of mine

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5 hours ago, Juarnerius said:

I think that could hardly count as "cheating". Unless someone is willing to argue that cutting out a neck with a bandsaw is cheating, or bending sides with an electric device.

 

That is a very nice idea, keeps it all clean and gathered. Thanks for sharing!

 

Wow that sounds pretty badass. Oil painting has always been a platonic love of mine

Yeah, it was pretty cool, I learned a ton of stuff working in the materials lab. 

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17 hours ago, Julian Cossmann Cooke said:

 

I also use a coffee grinder starting out -- I cheat? -- to start out with a finer consistency, reducing the time.

 

I've tried that... wasn't happy with the results. I'm not sure of the reason, but it seems like the  particles took on some sort of charge. Tended to want to clump once they were mulled into  the varnish. Maybe I'm blaming the grinder without reason, but had no difficulty when a m/p was used on the same lake and same varnish.

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1 minute ago, Fossil Ledges said:

Yeah, it was pretty cool, I learned a ton of stuff working in the materials lab. 

Did that include washing linseed oil? I recently read a thread from a french luthier here that washes it with lime water and then cooks it with some more lime. He then uses that oil as a coloring ground on his instruments in the white, and i have to say i was pretty impressed by his results. I cooked my raw linseed oil that was washed with salt water at 280 degrees for 4 hours, and even though it got darker, it did not come even close to what he shows in his pictures. What do you think?

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While i'm at it and so as not to divert too much from the original post, what kind of reds do you guys use? So far i made a madder red that i like, and then some oranges and pinks. Then i tried with cochineal but i only seemed to get different shades and hues of purple or fuchsia

Madder red:
idrossido.thumb.jpg.8bbae8867bfc5c07ba70d2f043db6652.jpg

 

 

 

 

 

 

 

 

 

 

 

Cochineal purple and fuchsia:

cochineal.jpg.788ac5128809280b73aae9fa2bc6170c.jpg

fuchsia.thumb.jpg.11540437d0ac231800950f1970e0022c.jpg

 

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23 hours ago, Juarnerius said:

That is very intriguing to read. Do you mean that you mix the wet pigments with oil and then the water separates like when you are washing the oil?

After you precipate your lake pigments you get a slurry in the pot. I filter off as much water as I can by filtering through a cloth and then 'mix' it in a pot with turpentine oil at low temperatures (maybe 60 C) This needs stirring to make a sort of emulsion. At some point you can knead the mass and by just pressing on it you can squeeze the water out. I don't care if eventually a little water remains in the paste as long as I can blend it in my varnish.

Good luck.

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40 minutes ago, Andreas Preuss said:

After you precipate your lake pigments you get a slurry in the pot. I filter off as much water as I can by filtering through a cloth and then 'mix' it in a pot with turpentine oil at low temperatures (maybe 60 C) This needs stirring to make a sort of emulsion. At some point you can knead the mass and by just pressing on it you can squeeze the water out. I don't care if eventually a little water remains in the paste as long as I can blend it in my varnish.

Good luck.

I have had good luck in converting water-based pigments such as Michelman rosinates  into linseed oil by evaporative heating of the water and oil mixture while constantly running a lab stirrer shown below. Just don’t let the linseed oil evaporate or cross-link. I don’t know if this works for all water-borne pigments, but with the right equipment you can try anything.

 

F5637275-7D64-4F5D-9FCA-E53FBFF7BEC9.jpeg.f14f0a85e34f7a6c068784a6680823fc.jpeg

 

 

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15 hours ago, Fossil Ledges said:

In grad. school we had a ball mill and a pigment grinder. The ball mill could be used wet or dry and we used to let it run over the weekend. The pigment grinder had to be used wet and you had to monitor it. The grad. art department painters would re-grind and reconstitute antique oil paints which were no longer made. I used to use it with cochineal and it worked well for me.

Are you saying the pigment can be reclaimed from dried out tubes of oil paint? There are several really great pigments like brown  madder and orange alizarin which as far as I know are no longer made.

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6 minutes ago, nathan slobodkin said:

There are several really great pigments like brown  madder and orange alizarin which as far as I know are no longer made.

You can make madder brown by precipitating the madder extract with iron sulphate. Also (i haven't tried this one though) according to Sacconi you can make madder orange by precipitating the same extract with a tin salt, "which, with the addition of lime, increased in intensity"

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6 hours ago, nathan slobodkin said:

Are you saying the pigment can be reclaimed from dried out tubes of oil paint? There are several really great pigments like brown  madder and orange alizarin which as far as I know are no longer made.

Yes, that is why they do it. Just be careful handling the stuff, some of the older pigments have a lot of heavy metals and are fairly toxic.

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If they are water soluble pigments, I grind them and then dry them. But mostly, I am just lazy and grind them in turp. or linseed oil. I also have a vibratory tumbler and that works pretty well wet or dry, just noisy. Having worked in a materials lab under contract, a lot of wasted motion wasn't tolerated, if the chemistry is the same molecular to batch and batch to molecular, one takes the shortest path to the finished product that is chemically what it needs to be. I choose to believe that the old masters did not waste a lot of time on wasted motion or bizarre rituals either, they were pragmatic, and they consistently turned out some spectacular varnishes.

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11 hours ago, Michael_Molnar said:

I have had good luck in converting water-based pigments such as Michelman rosinates  into linseed oil by evaporative heating of the water and oil mixture while constantly running a lab stirrer shown below. Just don’t let the linseed oil evaporate or cross-link. I don’t know if this works for all water-borne pigments, but with the right equipment you can try anything.

 

F5637275-7D64-4F5D-9FCA-E53FBFF7BEC9.jpeg.f14f0a85e34f7a6c068784a6680823fc.jpeg

 

 

Michael,

Sorry to appear dense, but I'm missing something. Why not just air dry the rosinates and then cook them into oil like any other resin? 

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Lakes form as crystals.   There are a couple issues attached to this.   The crystals are very hard, and therefore difficult to mill evenly.   They are "slippery ".  These factors limit the wetting properties.   If the lake is grown around a softer substrate than this can be mitigated.

I suggest mulling in oil.  Mulling in varnish will shorten the dry to tack time of your varnish coat.

on we go,

Joe

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