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Refined Linseed Oil Vs. Cold Pressed Linseed Oil


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#1 LauraV

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Posted 16 March 2011 - 07:09 AM

In cleaning out our varnishing closet, I came across two bottles of linseed oil from Kremer Pigmente. One is their Linseed Oil, refined 73300, and the other is Linseed Oil, Cold-pressed 73020. I am wondering what, in a practical sense, the difference might be. The cold-pressed, apart from advertising that it is "from Sweden" is low acidity. What, if any, would be the advantage of that for violin-making? Does anyone have experience with these two products? Are there differences in drying times?

I might start some experiments....

#2 Salve Håkedal

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Posted 16 March 2011 - 07:20 AM

Linseed oil from a northern climate like in Sweden is said to have a larger percent unsaturated bonds, so it will dry faster and probably better.
(Someone else here will know the chemistry better than me.)

#3 joerobson

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Posted 16 March 2011 - 08:31 AM

Linseed oil from a northern climate like in Sweden is said to have a larger percent unsaturated bonds, so it will dry faster and probably better.
(Someone else here will know the chemistry better than me.)


I do not think there is a significant difference. More to the point: How old is the material?What does it look like? Were the containers open? did you hear a little "pop" from either when you opened them?
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#4 Jose Catoira

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Posted 16 March 2011 - 08:54 AM

Refined linseed oil is done by the addition of alkalis, if I am not too wrong.

The cold pressed oil from Kremer has sometimes, a little mucilage on it, but I don;t find that a big problem, can easily be washed away.

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#5 Craig Tucker

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Posted 16 March 2011 - 09:31 AM

Refined linseed oil is done by the addition of alkalis, if I am not too wrong.

The cold pressed oil from Kremer has sometimes, a little mucilage on it, but I don;t find that a big problem, can easily be washed away.



Mucilage is a natural product of flax seed, so, it would be there naturally, not added in, right?
Would it necessarily be something that would detract from the quality of a linseed oil varnish?

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#6 Bill Yacey

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Posted 16 March 2011 - 09:38 AM

You might find this interesting, a rather definitive article on linseed oil quality and methods of refining it.
http://www.tadspurge...Linseed_Oil.pdf

Interestingly, the author indicates Kremer's Swedish Linseed oil is not organic and has a tendency to yellow with time.

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#7 Craig Tucker

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Posted 16 March 2011 - 10:10 AM

You might find this interesting, a rather definitive article on linseed oil quality and methods of refining it.
http://www.tadspurge...Linseed_Oil.pdf

Interestingly, the author indicates Kremer's Swedish Linseed oil is not organic and has a tendency to yellow with time.


Excerpt;
"In the excellent but less well known “Medieval and Renaissance Treatises on
the Art of Painting”, Merrifield concurs with the usefulness of the procedure
outlined by Eastlake, and comments that it proceeds more quickly if the oil is
exposed to moderate heat, such as that of a low oven. This procedure, by a
combination of physical – the sand -- and mild chemical action – the salt being a base,
the water being polar – separates the oil from its water soluble fatty acids. The
predominant one of these in linseed oil is linolenic acid, Omega 3. This component has
also been proven to be a major potential cause of yellowing. Oil made by the procedure
below exhibits none of the negative characteristics associated with commercial linseed
oil. It does not skin or wrinkle, it dries hard without any gumminess, and, if used with
a chalk or other calcium carbonate, or aged in the light, it does not yellow perceptibly."

Interesting.

Thanks Bill, that was a great article.

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#8 Bill Yacey

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Posted 16 March 2011 - 11:20 AM

There's further information here, on the same website. http://www.tadspurgeon.com/justoil.php
This fellow has certainly done some in depth research that is very relevant to our purposes as well.

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#9 Wolfjk

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Posted 16 March 2011 - 12:34 PM

In cleaning out our varnishing closet, I came across two bottles of linseed oil from Kremer Pigmente. One is their Linseed Oil, refined 73300, and the other is Linseed Oil, Cold-pressed 73020. I am wondering what, in a practical sense, the difference might be. The cold-pressed, apart from advertising that it is "from Sweden" is low acidity. What, if any, would be the advantage of that for violin-making? Does anyone have experience with these two products? Are there differences in drying times?

I might start some experiments....

Hi,
On a practical level,a few drops "cold-pressed" linseed oil make the brush marks disappear.

#10 LauraV

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Posted 16 March 2011 - 12:43 PM

This is very interesting! Of course, yellowing is not the huge issue for us that it is for painters. I, at least, have never looked at a violin and thought: "I bet this was a really nice color before the oil yellowed." Maybe my eye just isn't refined enough!

From the first part of the article: "Having significantly more linoleic acid, linseed oil has a tendency to dry faster, and also more of a tendency to yellow. " I got the idea that the acidity was related not only to the yellowing, but also the fast drying. But then later, in the section about the refining process, the addition of a base (either salt or calcium carbonate) is described as reducing the drying time "It dries in two days, more quickly in summer or when used with chalk."

Certainly, all this talk of calcium carbonate brings to mind certain mineral and pozzolana grounds that have been variously discussed....




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