Washing linseed oil

[not telling]

I don't know, Peter. I think you should take a swig of your linseed oil.

I don't deny that Swedish flax is superior (or wherever you're from)

But it will go rancid if you put the raw oil on a shelf, with no processing.

How would it not?

[David Burgess]

Reading what you guys are doing and all the troubles   It makes me wonder what the heck is wrong with the oil you are using? The cold pressed linseed oil I use doesn't even need washing to make great varnish, and for it to go rancid !? Never heard that would ever happen . Isn't there any flax plant farmers and linseed oil makers in northern US? Just a thought, you need to start with the right quality of linseed oil.

Peter, what makes you think that your "cold-pressed" Finnish oil from the paint store is only pressed, and not further refined?

 

I think others here are mostly talking about starting with an oil which has had no further refining or processing after pressing.

[Peter K-G]

I don't know, Peter. I think you should take a swig of your linseed oil.

 

 

Neither do I but I just did well not a swig, but I tasted both the first (edible) and the second one "cold-pressed". But didn't dare to taste Kremers refined. Both bottles have been stored on a shelf over a year in my workshop, they smelled and tasted just fine.

 

David, of course it is refined to some extent otherwise it wouldn't be suitable to bottle and sell.

[not telling]

I just got an email from the delightful people at Flora. Their oil, raw...first-pressing, unrefined, has been extensively tested. It is fine to not be refrigerated for five days. Beyond that and it starts to go. So it can be sent to the store; other than that, must be refrigerated.

My question was...at what point does hand-washing a raw and unrefined oil make a shelf-stable oil?

Brave man, tasting your oil. I don't think I would taste the hardware store version, but that's me.

[FredN]

I'm pretty sure there is an abundance of literature on refining linseed oil on the internet, so i'll describe a brief history on refining that seems interesting-

 

"During the great activity of the 12th and 13th centuries, methods have evolved for the refining of oils by the addition of a small quantity of drier, followed by heating and continual skimming.  The use of white lead as a drier and the bleaching of the oil in the sun with frequent agitation were practiced during this period. In about the fifteenth century refined oils were produced by boiling with pumice stone and calcined bone, and skimming. One ounce of white copperas was then added to a quart of oil, which was put in the sun for days. Such an oil was bright, clear, and pale, and it would dry more quickly then ordinary linseed oil because of the manganese content of the copperas. The discovery that linseed oil could be converted into a varnish by means of litharge  is attributed to an Augustine monk. From this period on, until the beginning of the last century, the refining of drying oils consisted mainly in the production of crude boiled oils by heating with various metallic salts and the bleaching of oils by sunlight.

The first reference to the refining of oils by chemical means was contained in a patent by Gower in 1792. He described the use of sulfuric acid for the purification of such oils as linseed."  (The acid carbonized mucilage products )

 

The literature has oil classified as "Alkali Refined" as the best oil for varnish, maintaining clarity at hi temps.  fred 

[David Burgess]

Brave man, tasting your oil. I don't think I would taste the hardware store version, but that's me.

I'll guess that any reasonably experienced man has tasted their own oil, even if it was by accident.

 

Haven't knowingly tasted anything from the dudes at the hardware store.

[Melvin Goldsmith]

There is SO much crap related to all this. I use cold pressed oils from Kremer, never needed to wash them or treat them and never had problems. 

When you take a natural product from a plant that has evolved for a purpose over millions of years you should give it some RESPECT. Trees shed resin to be the best thing they can give against all ingress of climate and pest against an injury to their bark. The linseed has an oil that will preserve the seed beautifully....why do we humans think we need to interfere with and change the chemical make up of these things so much? I find they work best interfered with least.

Cold pressing of oils has developed a lot in the last few hundred years. Old methods for raw extraction might well have needed some refining but Modern centrifugal cold press technology will give a very pure sample. 

Sourcing the right oil and a reliable resin  from known sources and species/location are much more important to me than trying to treat some kind of bastard oil or resin from who knows where according to the dubious chemistry claims of colleagues whose varnish still seems to be having problems.....sorry if that sounds rude...I just said what I was honestly thinking.

[David Burgess]

 

Sourcing the right oil and a reliable resin  from known sources and species/location are much more important to me than trying to treat some kind of bastard oil or resin from who knows where according to the dubious chemistry claims of colleagues whose varnish still seems to be having problems.....sorry if that sounds rude...I just said what I was honestly thinking.

Probably needed to be said.

I don't take it as rude at all. Just some "cut to the chase" stuff, for those who might be interested.

[tango]

Hello all

 

Sorry me too.

 

I don´t know why people who are learning change things of a well known master recipe.

Don´t you see the result showed here?

Why waste time?

The slow colofonia varnish recommended here with a cold pressed oil works well.

"Copy the masters before change what you don´t know" is my thought. 

 

Regards

Tango

[not telling]

I'll guess that any reasonably experienced man has tasted their own oil, even if it was by accident.

 

Haven't knowingly tasted anything from the dudes at the hardware store.

There you are.  Do you find yourself uttering phrases such as, "That's what she said" more than...never?  If so, seek help.  Meh, I just can't think of anything appropriately inappropriate to say.  This is a rare, sad day for me-- I am fresh out of raunchy.  

So really.  I'm just asking a simple question.  Is it possible to wash a raw oil to the extent that it becomes shelf stable?

Someone has to know the answer to this.  I can't use Kremer right now, it'll have to be some version of the great unwashed raw oil in the health food store, and I don't mind doing the processing.  I'm still shocked at the prices for Kremer stuff, even if it is great (and it is). 

 

I'm doing the normal washing routine for the flax oil.  I admit the magnesium sulfate thing is out there, but hemp oil is rather outrageously mucilage-y.  It's greenish-black to begin with and there is no end to the fat.  I am willing to try whatever a chem-e says to try.  Don't go running with that, David.  That's not what I mean.  Anyway, Tango is probably right here.  If I want to play with hemp oil I should just wash it more, not do weird stuff with it.  They definitely didn't have epsom salts in Cremona.  mea culpa

[joerobson]

When to wash linseed oil:

If the oil is green rather than gold.

If stuff settles to the bottom of the container.

If you are not sure about the above.

If you just want to eliminate the variables.

 

Does it matter to the varnish?

Yes.  Good varnish can be made from un-washed or poorly processed linseed oil...but it is more difficult.

 

Is most oil from major pigment and art supply firms washed?

Yes.  It is worth the "washing" to extract all the suspended organic material because they can be sold at a large profit as cattle feed.

 

Do not expect consistent results from varnish making if you use flax oil marketed as a food product.

 

on we go,

Joe

[not telling]

When to wash linseed oil:

If the oil is green rather than gold.

If stuff settles to the bottom of the container.

If you are not sure about the above.

If you just want to eliminate the variables.

 

Does it matter to the varnish?

Yes.  Good varnish can be made from un-washed or poorly processed linseed oil...but it is more difficult.

 

Is most oil from major pigment and art supply firms washed?

Yes.  It is worth the "washing" to extract all the suspended organic material because they can be sold at a large profit as cattle feed.

 

Do not expect consistent results from varnish making if you use flax oil marketed as a food product.

 

on we go,

Joe

Thank you.

 

That helps!

[David Burgess]

There you are.  Do you find yourself uttering phrases such as, "That's what she said" more than...never?  If so, seek help.  Meh, I just can't think of anything appropriately inappropriate to say.  This is a rare, sad day for me-- I am fresh out of raunchy.

There's kind a cute gal at one local hardware store which many of us local fiddlegeeks  frequent. She may not really be spectacularly cute (and the pros and cons have been discussed at length in the local gym and elsewhere), but she manages to be pretty seductive in a hardware store environment, sometimes even competing with threaded fasteners and aluminum sheet.

[not telling]

??

Fascinating, David. I don't see what this has to do with...hmm.

I may be spectacularly cute, but I make up for it with my total ignorance and my thousands of questions. Right. Well, I'm learning or at least trying to. Anyone?

[Michael_Molnar]

Avoid oxidation of linseed oil by storing it in small containers that have little or no air. Plastic containers can be squeezed to minimize the air pocket. Also, store this in a dark, cool cabinet. A refrigerator is an ideal storage place, but keep the containers in a light-tight box or wrap.

 

I suspect that those who have issues with it turning rancid are buying raw oil meant for consumption rather than varnish making.  I am told that these are processed differently. Get your oil from artist/varnish supply houses; otherwise, you are looking for trouble. Of course, if you are into masochism, ignore my advice.   I think bacterial contamination can be one problem. In any case, follow Robson's advice. He is the expert in this matter.

 

Mike

[MikeC]

"the manganese content of the copperas"

I thought copperas was iron sulfate,  or are they both called copperas?  

 

"epsom salts not available in Cremona"

the salts were discovered in Epsom in England in the early 1600's according to what I read on the internet

and as everyone knows...

"everything you read on the internet is true"

[not telling]

Thanks, Mike (Molnar)! I don't necessarily think it's masochistic to process raw oil. It's fun. But that's probably what an OCD masochist would say. Ok...well...the parsimony angle--I can crunch the numbers in a scenario where I lose half the oil, and it's still so cheap to buy raw. But I realize you...and Joe...are right about the problems with edible oils. I should probably eat them. I still need to see what happens with the results with this oil and a future cook, and I guess I will just continue to keep it all cold.

Too bad one cannot buy white lead these days. But thanks to FredN for that excerpt (source??)

I think there was lead in Cremonese varnish. That wasn't just a technique for the dark ages. Found in a chip sample off a Strad, if my memory is right. Source:somewhere on the internet

MikeC: Of course everything on the internet is true. I don't know why schools even bother to exist anymore, being so superceded in truthiness by the internets. I shouldn't have said Cremona didn't have the magnesium sulfate. There is no way to know. I'm sure as long as people lived in Epsom, the salts have been used. But anyway, put oil and spring water and a tablespoon of epsom salts in a mason jar, shake it, and observe. Pretty interesting.

[Peter K-G]

not telling

 

Did you read the first posts link? http://www.tadspurgeon.com/justoil.php?page=justoil In the middle of the page

it discribes degumming

 

 

Allbäck linolja (Swedish Cold pressed) tells the same in the product info Avslemmad = degummed

 

Faktablad om våra produkter.pdf

 

Copy/paste the text in Google translate

 

 

 

 

[not telling]

Oh yes...I did see that. it's overwhelming. I got distracted by "bleaching earth" and ran to my cupboard to make sure I still have the bentonite. 

 

I liked the just oil piece a lot. I have to read all of that stuff more than once though.

 

Thanks for the other thing. I'm on my phone now but I look forward to reading the translation later.

[Michael_Molnar]

I know varnish makers who use Allbäck. I guess it is the de-gumming process that eliminates going rancid.  

[MikeC]

 But anyway, put oil and spring water and a tablespoon of epsom salts in a mason jar, shake it, and observe. Pretty interesting.

 

I'm curious now,  will have to try that. 

[not telling]

http://lipidlibrary.aocs.org/processing/degum-intro/index.htm

Yes, MM. I'm bad about skim reading. But I got that water does it. I wonder when water does it. After1 washing? 19? Doesn't matter. This is what refrigerators are for.

That chart...the 20 processes I have to learn... Kremer's looking like a damn bargain basement product.

[FredN]

Hi Mike C- the term is "white copperas",  which is zinc sulfate and zinc is classified as a slow but thorough drier. I don't know where the manganese comes from in the article.

 

Hi not telling- the historical quote is from  Protective and Decorative Coatings ,   edited by Mattiello, 5 vols, 1942.  They are based on compilation of articles by researchers on the title's subject. I tried to post some of data on linseed oil but I found out my scanner does not like my new computer. As I mentioned in earlier posts, the 1940's are a point where the industry converted to synthetic resins (really just rosin chemically altered) ended research on the natural resins.

 

Like varnish, air has to be excluded also from veg oils. Michael M's storing in a full container with no air, or using Bloxygen (nitrogen blanket) or just blowing in the container a few times (CO2) also works.

 

Me?  I stick with Kremer Natural/Swedish? (hate to go downstairs just to check).  Since I go to temps hi enough to brown or precipitate any inclusions, 500F, I have no need to get out the mucilage break.  Oil so prepared is clear, a darker brownish color, not gold/bright as from washing, but i like that. Heating also rearranges the bonds in the molecule so it is receptive to adding oxygen, and will harden to a film in a desired time.  fred

[not telling]

The color of my IPA is reminding me of oil, so I figured I'd better give up and log back in.

Thanks for the reference, Fred. 5 volumes! Yes the 40's were great years for industry, not so much for the knowledge of historical processes being passed on as vocation. If you get your scanner going maybe you'd trade a copy of your book(s) for something? I also have lots of books. Also, thanks for the tip to blow into jars of oil to inhibit oxidation.  I am light years from being able to think of that myself or even to puzzle out why that would work, but cool idea.

Manganese oxide is yet another alternative to lead and the zinc sulfate. Or just the manganese. I found references to that in http://archive.org/stream/chemistryoflinse00frierich/chemistryoflinse00frierich_djvu.txt , i think. I doubt there is enough manganese in bentonite to create a drying action, but there's something else to think of.

Who on here works with raw oil...what siccatives, if any, have those people tried? Where is Roger Hargrave? *grumble*

[Jim Bress]

On 12/13/2013 at 1:48 PM, Roger Hargrave said:

 

That could be, but in order to wash it, you really don't need to heat oil at all. You don't need sand either; just oil and water in a jar. Shake it up every few days for a week and leave it for a week to settle; sometimes it goes quicker. Siphon off the good stuff leaving the crap. You can wash it more than once if you are really keen. The process is really easy. In fact it’s one of the easiest things about varnish making. 

Question for anyone not just Roger.  I've started washing Kremer's Swedish cold pressed linseed oil as described in the bass blog.  The mixture separates into 4 layers from top to bottom there's a clear(ish) yellow layer, followed by a sludgy yellow slop layer, followed by a thin white layer, then the rest is water.  My question is what's the crap and what's the good stuff?  I'm pretty sure the white layer would be crap, but what about the sludgy yellow layer in the middle?  Is it crap or good oil that happens to have a lot of water in it?

Thanks,

Jim

On 8/13/2014 at 6:30 PM, Melvin Goldsmith said:

There is SO much crap related to all this. I use cold pressed oils from Kremer, never needed to wash them or treat them and never had problems. 

When you take a natural product from a plant that has evolved for a purpose over millions of years you should give it some RESPECT. Trees shed resin to be the best thing they can give against all ingress of climate and pest against an injury to their bark. The linseed has an oil that will preserve the seed beautifully....why do we humans think we need to interfere with and change the chemical make up of these things so much? I find they work best interfered with least.

Cold pressing of oils has developed a lot in the last few hundred years. Old methods for raw extraction might well have needed some refining but Modern centrifugal cold press technology will give a very pure sample. 

Sourcing the right oil and a reliable resin  from known sources and species/location are much more important to me than trying to treat some kind of bastard oil or resin from who knows where according to the dubious chemistry claims of colleagues whose varnish still seems to be having problems.....sorry if that sounds rude...I just said what I was honestly thinking.

You're probably right, but I've already started washing before I found this thread.  Are you saying unwashed is better or just not necessary?

Thanks again,

Jim