Home Forums Explore Media Oil Painting The Technical Forum Washing Linseed Oil

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  • #991425
    joshuaw
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        When I first started oil painting I was guided by an employee through an art supply store picking out paint, brushes, thinner, a palette, and then it was time to pick a medium. The salesperson asked me what kind of painter I am, and I had only been using acrylics for a couple years before I decided to make the dive into oils so I had no clue what to expect of my future needs as an oil painter; anyway, he suggested I purchase a small bottle of cold pressed linseed oil because according to him it was the best. So I did. It was just a small 2 oz bottle of Gamblin cold pressed linseed oil. Turned out I used the CPLO sparingly on only one occassion, and later (and until today) I opted for alkyd mediums and rarely stand oil. The CPLO label said it was prone to yellowing so I was turned off by it, and in fact, oil that had dried on the outside of the bottle and on the threads of the bottle had dried to an orange amber color. Moreover, the oil itself was an amber color.

        So years later I’m looking at this small bottle thinking, “Gee, what a waste”, and decided to do some research to see if I could find any use for it, or decide to toss it. I first came across this website: It says to wash linseed oil in various methods, but seemed a bit wild with it’s use of names like Van Eyck and Rubens and claims to their “secret/lost” mediums, and further searching led me to Tad Spurgeon’s website, which also seemed a little whacky with bold claims about the failings of alkali refined linseed oil and more. Both websites advocate the benefits of cold pressed linseed oil and that it should be “washed” with water or salt water, and there are mentions of other ingredients for washing including lavender and vodka. So I was skeptical, but I decided heck, why not try it – I planned on tossing it anyway. At first I poured the oil into a half full jar of water purified by reverse osmosis (about 3 parts water to one part oil). It seemed at first to be a waste. It took days for the oil and water to separate, but eventually the oil did settle on top of hazy water with no “white line” in between as shown within the mentioned websites. The oil looked no different than before once it separated either. Alas, I tried this several more times. A few cycles I used hard salt water, which caused the oil and water to separate much more quickly after shaking the mixture and did eventually produce a white line. Each time I froze the mixture and poured the oil off from the top, and started the cycle over. Another note about the saltwater: I had to be much quicker with pouring the oil off after freezing, as the white (white line) gunk under the oil would melt into the oil much more readily with the oil (I’m guessing because of the lowered freezing/melting point of saltwater). And eventually I did a couple last wash cycles of simply purified water. The last cycle came out a bit hazy, so I put the oil into a small glass jar, placed it in a ceramic bowl and poured boiling water into the bowl, surrounding the jar. A thin film of white solid formed at the bottom of the jar and I syringed the oil out. A couple months, after about 7 washings (I didn’t count) I now have very pale linseed oil. I sincerely apologize that I don’t have a before photo of the original bottle of CPLO. I really didn’t think anything would come of this. Attached are photos of the threads of the bottle before I bleached it in the sun (which worked, the dried oil went much clearer, but then turned amber yellow again in just days after storing in the dark), and the oil as it is now in syringes and a small bottle. I know this has been discussed on WC before, but I just wanted to post my results and present these thoughts: You have to take my word for it that this process does lighten the color of CPLO, but I’m not sure if it is worth the effort. The process isn’t at all difficult but it is time consuming, tedious, and annoying, and possibly costly (I lost about 50% of oil by my final yield). I am completely mad for having done this experiment starting with only 2 oz’s of oil. Nevertheless, I did learn something. Do you think this process is worth it? Do you agree with Spurgeon that modern refined linseed oil is no good, and do you have anything to back this up? I mean, in all fairness, I am basing the quality of my washed linseed oil off of its color, and by that same token alkali refined linseed oil is much paler than CPLO (walnut, poppy, and safflower being even paler of course). Furthermore, because an oil starts at one color doesn’t mean it will be as dark when dried in a thin film. Nevertheless, I trust my eyes and don’t want to use dark oil. Does anyone here know what the alkali refining process does to the chemical nature of linseed oil, does it remove “mucilage” (and is mucilage a real concern), and does this modern refining cause any detriment to the oil? Many thanks for your thoughts, please aim to provide as empirical sources as possible.

        EDIT: This is my first post so it isn’t allowing me to post photos, but I will post them to this thread ASAP. Furthermore, the link wasn’t allowed, but you can find it if you google “van eyck secret”.

        #1196437

        I agree modern linseed oil is really bad ,ive used homemade linseed oil its better for blending and and it doesnt drip, because all the chemicals used today it destroys the oil ,you need to buy organic flax seed oil and clean it at home, here’s a link that explains it..http://www.calcitesunoil.com

        http://www.paul-torres.com

        Paul Torres

        #1196406
        Gigalot
        Default

            I agree modern linseed oil is really bad ,ive used homemade linseed oil its better for blending and and it doesnt drip, because all the chemicals used today it destroys the oil ,you need to buy organic flax seed oil and clean it at home, here’s a link that explains it..[url]www.calcitesunoil.com[/url]

            [url]www.paul-torres.com[/url]

            I do not trust words, show me scientific paper with tests. “Chemicals”, “destroys the oil”, “buy organic” are just words, which I heard billion times. Show me laboratory testing results, made by expert group, as serious argue to stop using refined oil.

            #1196383
            snoball
            Default

                Danny van Ryswyk used to have instructions on his site for washing oils using wood shavings as well as instructions on painting on copper but he no longer has that information on there. I am sure there are many tutorials online though on how to wash or purify different oils.


                If you're asking me for advice, I'm going to assume that you've run out of rational options.
                My work on Facebook

                #1196438

                the best way to wash organic flax seed oil is by using psyllium husks…and then it becomes linseed oil
                Sincerely
                P

                Paul Torres

                #1196394
                Anonymous

                    Alkali refining will neutralize and eliminate the reactive free fatty acids, which are bad guys.

                    #1196439

                    the reason they use alkali and all the other chemicals is because it’s great for commercial mass production but its not the same method that the old masters used which is superior they washed the flax seed oil in their studio by means of bread, vodka, psyllium husks etc..but no chemicals

                    Paul Torres

                    #1196440

                    A website that explains it http://www.calcitesunoil.com :)

                    Paul Torres

                    #1196395
                    Anonymous

                        vodka is famous for it’s powerful toxic antiseptic solvent chemical content of C2H5OH.

                        #1196432
                        joshuaw
                        Default

                            Thanks Sid- So do you consider alkali refined linseed oil superior to CPLO? And by removing the free fatty acids, does this change the pH of the oil? I’m thinking if I ever go through with this process again I’ll test the pH before and after, start with a larger amount of oil obviously and take photos throughout.

                            But again, aside from conjecture I still haven’t much evidence to indicate that CPLO is better or worse than alkali refined, or vice versa – paint manufacturers inherently disagree on the subject by their chosen binder (Old Holland = CPLO, Michael Harding, Gamblin, list goes on = alkali refined). And written sources disagree as well. Furthermore, yellowing is likely a product of any form of linseed oil, yet again, instinct would cause me to trust the palest option. I guess the real distinction to make here is whether washed CPLO or alkali refined is best and are any offspring forms of these oils (stand, sun bleached, etc.) any better? This would require chemical analysis and lengthy testing, which I doubt any one or group has the economic motivation to do so.

                            #1196433
                            joshuaw
                            Default

                                vodka is famous for it’s powerful toxic antiseptic solvent chemical content of C2H5OH.

                                Indeed, cleanses the soul, but I prefer it suspended in beer or tequila

                                #1196441

                                Sid, I still recommend you try the homemade method of cleaning I like the oil far better than the art store one, ive tried both…

                                Paul Torres

                                #1196396
                                Anonymous

                                    Thanks Sid- So do you consider alkali refined linseed oil superior to CPLO? And by removing the free fatty acids, does this change the pH of the oil? I’m thinking if I ever go through with this process again I’ll test the pH before and after, start with a larger amount of oil obviously and take photos throughout.

                                    Josh, No, I really don’t know which one of those, or whether either one is better, I suspect that they all work ok, with certain differences regarding each. I have cold pressed linseed among many other oils, etc. but I don’t know which is better. I mainly use the cpo to make a little paint now and then.
                                    BTW, I don’t worry about yellowing of normal linseed oil and don’t think it is a problem.
                                    Removing acids will change the pH and the acid number somewhat. I have washed some alkali refined oil and some raw hardware oil and checked their pH.
                                    Here is a post from some testing/washing I did on some oils. I bet that if I had done some alkali treatment on the raw linseed oil, that I would raised the pH, and probably then made it less dark too, similar to the Utrecht oil maybe.

                                    paint manufacturers inherently disagree on the subject by their chosen binder (Old Holland = CPLO, Michael Harding, Gamblin, list goes on = alkali refined). And written sources disagree as well.

                                    Omg, do they ever, whatever they are selling, well that is the stuff :lol:
                                    Graham says walnut is it.
                                    Mussini says damar makes theirs the best.
                                    Blockx says poppy is the stuff.
                                    Those guys say CPO is it,
                                    blah, blah, blah, etc. whatev’s

                                    Sid, I still recommend you try the homemade method of cleaning I like the oil far better than the art store one, ive tried both…

                                    I don’t doubt that PT, I think washing is all good :D and I know a lot of people like that calcite sun oil a lot too and a friend recommended it to me also.

                                    #1196407
                                    Gigalot
                                    Default

                                        Agree with Sid, refined oil is less yellow than Cold pressed.
                                        Free fatty acids are unwanted impurities, according Smitsonian’s theory these free acids do not dries properly, makes oil film weaker. Highly acidic natural resin is also drying inhibitor.
                                        The first step in industry to manufacture high quality alkyds from vegetable oils is free fatty acid neutralisation.

                                        Sun-thickened oil which I made myself from refined oil, dries quickly, even faster than cold pressed oil but without odor and less color.

                                        I have 20 years old bottle with sun-thickened oil I made from artist’s grade refined oil and it works perfectly. It is absolutely PH neutral, 1/3 part is 1% sodium bicarbonate solution and 2/3 part is thickened oil. I also add 0,5 gram Zinc White to a bottle with my oil medium ,prepared with this oil, to neutralize any free acids there.

                                        White clouds, which appears among water and oil boundary layer are soluble in oil at a temperature higher than 30 Celsius degree, and appears again at 20 degree or less. I guess, it might be oil soluble oligomer or something like it.

                                        #1196397
                                        Anonymous

                                            Yes, the triglyceride form of fatty acids (linoleic, linolineic acids) are the backbone building blocks of a dry solid oil film, you can think of them like the cinder blocks in a wall, all connected by polymerization, which is the mortar holding them all together. Free fatty acids are detached monoglyceride pieces of the normal tri-g fatty acids. They are very reactive and disrupt the matrix and don’t form a durable solid structure of paint film.

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