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Damar + linseed oil Ground/Clear Varnish


David A.T.
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13 hours ago, David Burgess said:

Drying time highly depends on the film thickness, and the level of UV exposure.

 

 

2 of my drops are a bit thick due to they are not diluted with thinner. The one in the middle is diluted and thin.

 Any explanation about the UV  action? As far I know in painting the oil dry with O2 that get in between oil molecules during drying and make the film hard. But UV i don't know how it physically works. 

From my experience I found difficult to have good Sun UV exposure with oil varnish because the outside dust come and stick to the varnish. So i dry through a Window.

 

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7 hours ago, David A.T. said:

Thank you for your article( great job !) and contribution in this post.

in the Tolbecque Book, there are  receipts with Damar and Mastic. 2 parts Mastic / 1 part Dammar./1 to 2part oil They are prepared at room temperature (or water bath, but not higher) and then diluted with Turpentine.  Due to Mastic cost I started only with Dammar - which is really a cheap resin and recommanded by the shop as similar to Mastic. But I probably miss the Mastic properties in my mixture.

The Hammerl book also recommand to cook at high temperature the resin. 

It could be an esay test to take one part of my mixture Dammar/oil/Turpentine and dissovle some Mastic in it.

Mastic isn't necessary and is not similar to dammar. You are wasting your time trying to make a cold dammar/oil varnish.

 

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6 hours ago, Michael Darnton said:

Mastic isn't necessary and is not similar to dammar. You are wasting your time trying to make a cold dammar/oil varnish.

 

Most varnish making is a waste of time, tilting at windmills. Thousands of pages have been written on the subject over the last five centuries. As a result, we already know what works, how to do it, and whether or not it is suitable for musical instruments.

 

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12 hours ago, David A.T. said:

 

2 of my drops are a bit thick due to they are not diluted with thinner. The one in the middle is diluted and thin.

 Any explanation about the UV  action? As far I know in painting the oil dry with O2 that get in between oil molecules during drying and make the film hard. But UV i don't know how it physically works. 

From my experience I found difficult to have good Sun UV exposure with oil varnish because the outside dust come and stick to the varnish. So i dry through a Window.

 

UV accelerates processes of oxidation and, in the case of drying oils, polymerization.

This is why uv "tans" bare wood - it's dramatically increasing the natural process of surface oxidation. 

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Quick update at D+5 days.

20210728_172656.thumb.jpg.7f33a0a872a4d692919032c5223d40c7.jpg

The drops do not stick to the finger, but they are soft. I can press them and feel the inside varnish is soft. Only the surface is ok.

Let s wait 3 days more. Then I will do an other test with more oil and more thinner (turpentine).

On the other side I tried to give some color to the mixture with Madder. It seems the color passed well in the varnish.

20210728_172610.thumb.jpg.faf733d61004c08f3bff4934d1e2b070.jpgI put a drop on ceramic and a mapple test plate on which some clear varnish was applied long ago. 

20210728_172640.thumb.jpg.b594f47da6d89b79f2674b8f33749dfa.jpg

20210728_172604.thumb.jpg.85aad2ccfc9b2296c3e8ff35e44c6362.jpg

It is yet much too thick though. But i feel this way interesting (at least for me).

 

I will let dry few days this stuff and start a new mixture.

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1 hour ago, David A.T. said:

Quick update at D+5 days.

20210728_172656.thumb.jpg.7f33a0a872a4d692919032c5223d40c7.jpg

The drops do not stick to the finger, but they are soft. I can press them and feel the inside varnish is soft. Only the surface is ok.

Let s wait 3 days more. Then I will do an other test with more oil and more thinner (turpentine).

Next time you do the tests on the glass, try to spread the drop of varnish more in some area, so that you can evaluate any differences between a thin and a thicker thickness, because the thickness greatly influences the drying.

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On 7/28/2021 at 7:22 PM, Davide Sora said:

Next time you do the tests on the glass, try to spread the drop of varnish more in some area, so that you can evaluate any differences between a thin and a thicker thickness, because the thickness greatly influences the drying.

I received the Kremer oil. Made 2 big drops at thin thickness to compare to mine (boiled oil). Let s now wait one week.

16277417592002252929104539892910.thumb.jpg.eeca4a4c1d6bc0c5612cfa5de72d7a1e.jpg

The Swedish oil (on the left) looks a bit more yellow once spread.

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After 1 week, the raw oil is at same state (liquid). The boiled oil is dry, does not move, but finger stick to it. It is clear for me now that the raw oil need to be processed priori to use (I will look for which minimum Tp) and the boiled oil require more than a week.

I will do a test to bind resin with both oil and see which one dry the fastest.

 

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31 minutes ago, David A.T. said:

After 1 week, the raw oil is at same state (liquid). The boiled oil is dry, does not move, but finger stick to it. It is clear for me now that the raw oil need to be processed priori to use (I will look for which minimum Tp) and the boiled oil require more than a week.

I will do a test to bind resin with both oil and see which one dry the fastest.

 

In oil and varnish drying tests, it would be useful to specify environmental conditions such as natural light in shadow behind the glass of a window or outside (no filter), the same but with direct sun instead of shade, also comparing to the test in the UV box and at what distance from the light source. UVs are the most responsible for the chemical processes that lead to the formation of a solid film, and vary greatly depending on the conditions mentioned above.

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1 hour ago, Davide Sora said:

In oil and varnish drying tests, it would be useful to specify environmental conditions such as natural light in shadow behind the glass of a window or outside (no filter), the same but with direct sun instead of shade, also comparing to the test in the UV box and at what distance from the light source. UVs are the most responsible for the chemical processes that lead to the formation of a solid film, and vary greatly depending on the conditions mentioned above.

It was natural Light behind the glass of a window, south oriented.  it is the area where I  let the instrument driing.

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26 minutes ago, David A.T. said:

It was natural Light behind the glass of a window, south oriented.  it is the area where I  let the instrument driing.

The amount of UV may not be sufficient, or at least it may take a very long time (weeks). This is why UV boxes are used, or exposure to light in the open air, or even direct sunlight, as some claim ancient luthiers did.

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Glass, as Davide is getting at, even uncoated, is a filter of light, and inhibits to some degree the passage of useful bands of UV radiation. Put it outside, and you will have better results. If you're worried about particulates, perhaps let it tack indoors before taking it outside. 

Boiled Oil is a term with more than one definition. The most common today is linseed oil that has been heat bodied with the addition of metal driers, such a lead, cobalt, manganese, etc. Simply washing linseed oil is sufficient for varnish making. You can then heat body it if you wish, but I don't find it necessary. The source of your oil as also very important. The region in which it was cultivated and the nature (if any) of pre processing are critical to the outcome of it's use in varnish. Cold pressed raw linseed oils from cold climates are generally superior for this purpose. Alkaline refined oils, such as the varnishmakers linseed oil from Wood finishing Enterprises, will behave differently from washed cold pressed linseed oils. 

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33 minutes ago, JacksonMaberry said:

... Put it outside, and you will have better results. ...

 

1 hour ago, Davide Sora said:

The amount of UV may not be sufficient...

Thanks much for your tips.As soon the Sun will show up I will put the plate outside.

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  • 4 weeks later...

I took some of the Damar/oil mixture and mixed with cochineal dissolved in water.

Then i heated during about 6 hours at 120°C to evaporate nearly completely the water.

It leaded to the red/violet color on the left sample (one drop I spread with finger).

But as still some bubles were showing presence of water in the mixture I did the bowling 2 hours more at 120°. Then it turned to yellow/Brown, sample on the right.

 

Do someone has an explanation : did the cochineal burned ?

 

20210903_210328.jpg

Edited by David A.T.
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Cochineal's most important dye chemical is carminic acid. Like most natural dyes, it's pH sensitive. 

To be honest, there is so much that you're doing that is off the wall and unnecessary with your experiments that it's hard to know where to start helping you. If you're having fun, then just keep going and don't worry about it. If you are seriously pursuing a good varnish, stop what you're doing, Dona good bit of reading, and work within the parameters of best practice. 

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15 minutes ago, JacksonMaberry said:

Cochineal's most important dye chemical is carminic acid. Like most natural dyes, it's pH sensitive. 

To be honest, there is so much that you're doing that is off the wall and unnecessary with your experiments that it's hard to know where to start helping you. If you're having fun, then just keep going and don't worry about it. If you are seriously pursuing a good varnish, stop what you're doing, Dona good bit of reading, and work within the parameters of best practice. 

I was also thinking to the pH. Thanks. I think I will continue my experiments. I don t want to bother you though. Was just asking a question.

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10 hours ago, JacksonMaberry said:

Not so much a bother - I want to see you succeed. I guess I'd recommend that instead of reinventing the wheel, you take a look at proven methods 

I read following books: Sacconi, Tolbecque(with lot of old receipts), Padding, Harmmel, Beament, Fry, Michelman, your article, M.Darnton's notes.

I used Sacconi with propolis but had to redo the instrument because it was too soft. I used Michelman but failed because too long to dry and color fade (I don t want to retry these receipts), I used one of Milans one but color was not enough also. So I am still looking for how to make the dye (from madder / cochineal) not fading in the oil/resin. The only way I managed  to keep the color was when I use alcoohol.

I also bought oil varnish from Harmmel but would prefer to prepare one because I know what I put in it.

I also view the strad articles how to make mineral dye (precipitate) and mix ot with the varnish before application. This way I did not try yet though.

I would like also to avoir to cook above  200°C for safety reasons . I don t have equipment to keep stable temperature.

I think you mean cooking rosin at high temperature when you say 'proven method' . Is that right?

I am experimenting simply because in all these book there are plenty of options that let the reader chose its own way. And when having too many books, receipts, opinion (good or not) finally one can get lost. I think I am not far from something stable.

 

Note : finally the Kremer oil drop dried through the window, but it took 3 weeks.

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24 minutes ago, Strad O Various Jr. said:

You shouldn't use liquid dammar solution from the art supply, you should get solid dammar resin from Kremer, if you are going to work with dammar.

I don t use liquid Damar. Yup, this is the case, I use raw resin piece.

16307375913494154796708628445816.jpg

Kremer oil and Damar cooked together :

16307377988794344141270974904941.thumb.jpg.fc19fcb6fd467d290ff4efa3b30f3880.jpg

which is a lot différent thant the result I got with 'cooked oil' from the shop. (First pics of the post) 

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51 minutes ago, Strad O Various Jr. said:

You shouldn't use liquid dammar solution from the art supply, you should get solid dammar resin from Kremer, if you are going to work with dammar. And make a varnish where turpentine is the biggest ingredient.

Sorry, but if one is making oil varnish for instruments, dammar shouldn't enter into it. And turpentine should certainly not be the biggest ingredient of anything. 

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1 hour ago, David A.T. said:

I read following books: Sacconi, Tolbecque(with lot of old receipts), Padding, Harmmel, Beament, Fry, Michelman, your article, M.Darnton's notes.

I used Sacconi with propolis but had to redo the instrument because it was too soft. I used Michelman but failed because too long to dry and color fade (I don t want to retry these receipts), I used one of Milans one but color was not enough also. So I am still looking for how to make the dye (from madder / cochineal) not fading in the oil/resin. The only way I managed  to keep the color was when I use alcoohol.

I also bought oil varnish from Harmmel but would prefer to prepare one because I know what I put in it.

I also view the strad articles how to make mineral dye (precipitate) and mix ot with the varnish before application. This way I did not try yet though.

I would like also to avoir to cook above  200°C for safety reasons . I don t have equipment to keep stable temperature.

I think you mean cooking rosin at high temperature when you say 'proven method' . Is that right?

I am experimenting simply because in all these book there are plenty of options that let the reader chose its own way. And when having too many books, receipts, opinion (good or not) finally one can get lost. I think I am not far from something stable.

 

Note : finally the Kremer oil drop dried through the window, but it took 3 weeks.

You mentioned my article, but you did not say whether you tried the technique.

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