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antonio
12-05-2001, 05:08 PM
For the past few weeks i have attempted to clean/refine my cold pressed linseed oil further by mixing it with water,shaking vigorously and allowing the mixture to separate into three separate layers. Top one oil, middle one mucilage(sp?) , and bottom layer water.
Everything is fine up to this point. I then place the bottle in the frig, wait until the water and mucilage freezes and pour off the oil.

After doing this several times (3 i think) there is almost no mucilage left. So i think i've cleaned it as much as humanly possible.

My problem is the cleaned oil. It's not crystal clear like the original oil. There's obviously still water left in the oil. In some sort of emulsion, correct?

How do i get the oil clear again?

Verdaccio
12-05-2001, 08:29 PM
You are following some technique similar to the techniques for cleaning linseed oil in Eastlakes book I assume? I have read about doing this, but have not done it myself. The thing that strikes me is they didn't really have the capability to freeze the water and muscelage off in the 1700s - well, perhaps in winter.

I wonder if the freezing and re-freezing process is having any molecular effect on the oil. Is it possible that you have changed the chemical composition of the oil by exposing it to those temperatures? Linseed oil changes when you boil it....

Hopefully someone like Titanium will post here soon - he may have better answers than I....

Scott Methvin
12-05-2001, 09:21 PM
Originally posted by antonio
After doing this several times (3 i think) there is almost no mucilage left. So i think i've cleaned it as much as humanly possible.

My problem is the cleaned oil. It's not crystal clear like the original oil. There's obviously still water left in the oil. In some sort of emulsion, correct?

How do i get the oil clear again?

Antonio,

I have cleaned my oil for several years.

First of all, you need to be sure you start with raw cold pressed linseed oil. (Not stand and not refined. You can't clean those two.)

Next you need at least a liter or 2. Any smaller amount is a waste of time. You will lose about a third of the original volume after you are done.

Large clear container with a sealable top. 1/4 oil 1/2 warm water and 1/4 air. Add about 10 glass marbles to make it shake/mix better. Shake it up about 100 times and let it separate in the sunshine, or next to the heater. Warmth speeds up the process considerably.

Make sure you let it fully separate, before freezing. It will get clear if you wait long enough. Freeze untill the water is SOLID, otherwise it may leak into the clean oil as you pour it off. If you can hear marbles rolling around, it isn't ready yet.

Do the same process about 10-15 times and you will have some beautiful clear oil that can't be bought anywhere. Great stuff for skies and other areas where yellowing is a problem.

I use it all the time and it dries great. Also adding lead shot to the final oil and storing it that way will speed up the drying time.

Even when you think you are done and the oil is clear, there are times where you will see an additional amount of water collect at the bottom of the container. (2 weeks or so) Always keep in glass bottles for storage, so you can see this. You can pour off the oil and throw away the last inch or so-with the water. I use old terpentine bottles.

It is a good idea to save a small amount of oil when you start so you can see how much progress you have made.

It is worth the time you put into it.

Good luck.

Einion
12-05-2001, 10:15 PM
Unless there is any emulsifying agent in the water you used (a mineral salt?) the cloudiness in your linseed oil is unlikely to be an emulsion I think. I don't know if it is applicable but non-drying oils sometimes become clouded when cooled below a certain temperature - this is fairly common with extra-virgin olive oil in cooler climates for example. This cloudiness does not always disappear when the oil is returned to room temperature, hence why one sees this on the shelves, and the usual remedy recommended is gentle warming (although why this is important for a cosmetic problem in cooking oil is beyond me!)

Anyway, you could try warming it in a double-boiler or even just a basin of hot water and see if it helps.

Einion

Verdaccio
12-06-2001, 09:11 AM
Ah ha! Scott, every time you post I learn something more. :)

So, say you have purchased Grumbacher Cold Pressed Linseed Oil. You wash it in the manner you prescribe.

Now, what are the working properties of this cleaned oil in comparison to the CP Linseed that you started with?

Is is smoother, less yellowing, dries faster/slower....
Would you use it straight, make mediums with it, mull paint with it...

Scott Methvin
12-06-2001, 10:20 AM
Originally posted by Verdaccio
Ah ha! Scott, every time you post I learn something more. :)

So, say you have purchased Grumbacher Cold Pressed Linseed Oil. You wash it in the manner you prescribe.

Now, what are the working properties of this cleaned oil in comparison to the CP Linseed that you started with?

Is is smoother, less yellowing, dries faster/slower....
Would you use it straight, make mediums with it, mull paint with it...

Hi,
I have only used Kremer cold pressed.
It is very thin, clear and I did a yellowing test in a taped box for 7 months and found no recouring yellowing.
I use it for everything. My medium is this oil and canada balsam, only. They are the same color.

antonio
12-06-2001, 04:59 PM
Originally posted by Scott Methvin


.

Make sure you let it fully separate, before freezing. It will get clear if you wait long enough. Freeze untill the water is SOLID, otherwise it may leak into the clean oil as you pour it off.
Good luck.

I think this is where i screwed up. I obviously didn't wait long enough for the oil to settle completey. The oil was still cloudy when i placed the bottle in the freezer.
Ok... so how long does it take for the oil to clear/settle inself before i can freeze the water part?.....can you give me an approximate time frame?......3 days?.....a week ?.....a month ?
Thanks for the info......antonio

Scott Methvin
12-06-2001, 07:07 PM
Originally posted by antonio


Ok... so how long does it take for the oil to clear/settle inself before i can freeze the water part?.....can you give me an approximate time frame?......3 days?.....a week ?.....a month ?
Thanks for the info......antonio

It usually takes about 4-5 days. When it is clear, it"s ready to freeze. Cold does make it cloudy (Like Enion said earlier.) Keep it in a warm place at all times.
When you pour off the clean oil-after freezing the water and junk, notice how cloudy it is. As it warms to room temp, it clears again.
Linseed oil has all kind of weird quirks.

I wrote a web page a while back on this ---go to

http://www.mauigateway.com/~donjusko/washlinseed.htm

C_Verdun
12-08-2001, 10:55 PM
Originally posted by Scott Methvin


Hi,
I have only used Kremer cold pressed.
It is very thin, clear and I did a yellowing test in a taped box for 7 months and found no recouring yellowing.
I use it for everything. My medium is this oil and canada balsam, only. They are the same color.
Hi Scott,
I'm just starting to grind my own paints and I'm planning to use oil from Kremer. Can I ask you a few questions?
Do you use the Swedish oil or the German? What is your opinion on the difference of mucilage content between the two?
(Supposedly the less mucilage the better anti-yellowing qualities)
Thanks

Scott Methvin
12-09-2001, 10:40 AM
Originally posted by C_Verdun

Hi Scott,
I'm just starting to grind my own paints and I'm planning to use oil from Kremer. Can I ask you a few questions?
Do you use the Swedish oil or the German? What is your opinion on the difference of mucilage content between the two?
(Supposedly the less mucilage the better anti-yellowing qualities)
Thanks

Hi C,

Because I am going to wash the oil anyways, I get the cheapest raw cold pressed they sell. The 5 liter size. It the kind "with deposits". The swedish is far more expensive and I could not tell the difference after a few cycles-because I tested them both.

I believe the mucilage, or aqueous material in the oil does make it more yellowing. Linseed oil is a mysterious substance though.

One batch will differ from the next and so all bets are off. The time of year seems to effect the washing as well. Go figure?

Give it a shot. I have paid as little as $42 for 5 liters of the cheap stuff. The Swede is around $125 for same amount. If I didn't wash it, I would use the swede.

timelady
12-09-2001, 12:53 PM
Can I repeat the earlier question? What is the benefit of using oil cleaned in this way? Less yellowing? Drying time? Other?

Now that I'm doing more and more acrylic paintings it has taken away the need for me to rush oil paintings (in the very loose sense that they can be rushed) so I'm starting to experiment with more oil glazes rather than quicker drying mediums. Tried a turps/linseed/beeswax medium today that is fan-bloody-fastic. Of course I don't expect to put on the next glaze for a few weeks! Funny how using acrylics has given me the chance to do more with my oils. :)

Tina.

Scott Methvin
12-09-2001, 02:20 PM
Originally posted by timelady
Can I repeat the earlier question? What is the benefit of using oil cleaned in this way? Less yellowing? Drying time? Other?

Tina.

It can be washed to the point where it is almost as clear as water. The yellowing is completely eliminated. This is the reason.
You get an oil that is, in my mind, as good as it ever gets.

As someone who has made his own amber varnish, among other things related to oil painting, the science and experimentation are a source of joy. I really like to take my materials to the limit and the washed oil has become a standard.

Maybe the effort I put into these things makes me have just a little more respect for the paint and medium I use. Add a panel with real gesso and you'd have the trifecta.

It's fun too.

timelady
12-10-2001, 10:12 AM
Well, if it's fun then I'd better try it. :) Thanks.
Tina.

antonio
12-12-2001, 01:04 PM
Originally posted by Einion
Unless there is any emulsifying agent in the water you used (a mineral salt?) the cloudiness in your linseed oil is unlikely to be an emulsion I think. I don't know if it is applicable but non-drying oils sometimes become clouded when cooled below a certain temperature - this is fairly common with extra-virgin olive oil in cooler climates for example. This cloudiness does not always disappear when the oil is returned to room temperature, hence why one sees this on the shelves, and the usual remedy recommended is gentle warming (although why this is important for a cosmetic problem in cooking oil is beyond me!)

Anyway, you could try warming it in a double-boiler or even just a basin of hot water and see if it helps.

Einion

Excellent suggestion !......i took your advice and gently heated the cloudy .washed oil and after a hour or so it cleared up. It became as crystal clear as the original oil except that it's a bit less yellow.
But after leaving it on the shelf i returned home 6 hours later to find the oil cloudy . So when the washed oil returned to room temperature it became cloudy again.
I'm totally baffled because the original cold pressed oil i began with has always remained crystal clear at room temp. their in the same room , on the same shelf.
No matter where i buy my cold pressed linseed oil/and or walnut oil from (kremer,doak, pearl ,.health food store, etc) they ALL become cloudy after washing and i'm at a complete loss as to how to make the washed oil clear/transparent like the original pre-washed oil i begin with.
I've used new york city tap water/ water from my friends in new jersey (a different water supply), bottled water etc.
I've also let the oil stand/rest undisturbed for over a week and still its cloudy and i'm unable to see through it.
Any suggestions out there?

autolisp
12-19-2004, 04:06 AM
Is it possible that you have just got a very good emulsion, with incredibly tiny particles. If this is the case you might have to wait some time for the oil/water separation to complete its cycle. But it should separate eventually!

autolisp

Beancrusher
12-19-2004, 10:30 AM
You might be seeing some "wax" that has crystallized in the cooling / freezing process.

Most natural veg oils have at least some very small portion of the oil ( remember all oils are a mixture of various length fatty acid chains atatched to a glycerine molecule) that has the characteristic of "wax". Depending upon the melting point of the "wax", it may stay visible as cloudiness at room temperature. This is not really an impurity in the same sense as the mucilage fractions.

All the bottled salad oil you see on the grocery store shelves is what the trade refers to as RBD, refined, bleached, and dewaxed. Other wise in the process of storage and transportation during winter months, the wax portion of the oil turns the bottle on the shelve cloudy. Nothing wrong with it, but who wants to buy cloudy cooking oil.

The length of time and repeated processing that Scott uses may effectively remove that portion. If you want to check it out, just warm it up a little farther than room temp, probably won't take much, and see if it clears.

Bruce

rroberts
12-19-2004, 12:08 PM
Just curious ...
Has anyone tried this with walnut oil? Would there be any need to clean walnut oil this way?

So far, I've preferred walnut over linseed, but am willing to experiment a bit. One of the forum threads mentions that Robert Doak uses a mix of linseed/walnut oils, but there was no mention of proportions.

Thanks.

Scott Methvin
12-24-2004, 11:53 AM
No. It is because you are not patient enough to let it get completely clear before you freeze. Keep the apparatus in a warm place and wait it out. I have a friend who kept trying to speed things up and he wasted alot of oil in the process. It takes at least a week to completely separate. Sometimes even longer. If you agitate it more than once, it will also drag out the process to no benefit.

As far as the water used, I started out using the bottled water that I used to have delivered in 5 gallon jugs. It worked great too. Then I just began using the hot water out of the tap (Orange county CA) It isn't quite as good but has worked for years without a problem.

Washing oil is for people that make their own oil paint. Otherwise, don't waste your time on it. The way the oil dries and handles is the main reason for going to the trouble. The non yellowing is good too, but not the main reason.