Full Chisel Blog

May 11, 2011

More fun with raw linseed oil

Here is another example of just how clever our ancestors were when it came to figuring things out.  This is a process of using kieselguhr or rottenstone or Tripoli or fossil flour or infusorial earth or fullers earth or diatomaceous earth for they are all the very same thing, to turn raw linseed oil into ‘boiled’ linseed oil without heat.

Above is the control picture of raw linseed oil straight from the can.  I also found I could easily remove the labels from the jars by carefully heating them up with an alcohol lamp then gently pulling them off, sure beats scraping them off with a blade.

Below is one tablespoon of rottenstone in the raw linseed oil and shaken up about a half a dozen times before allowing it to settle.

The photograph below shows the mixture after a few days settling, there is still some turbidity.

And this picture of how the stuff looks after sitting a couple of weeks.  It has clarified more than the chalk/raw linseed oil mixture I did before, but is slightly darker overall.

After a few more experiments I will make a sample of all of these altered oils with the glass smear test and samples on real wood.  I have actually used some of the washed linseed oil on wood and it dried in 24 hours.



  1. Hi,

    Thanks for sharing all the great information!

    Does this way of boiling work for other oils as well? Say, walnut or poppy seed oil?


    Comment by Philip R — May 11, 2011 @ 12:20 pm

  2. Philip,

    Welcome and yes all of these methods of ‘boiling’ raw linseed oil work on the other drying oils as well, walnut oil, hemp seed oil and poppy seed oil. All of these methods and others will be in the Shellac, Linseed Oil, and Paint – Traditional 19th Century Woodwork Finishes, coming out as early as next week.


    Comment by Stephen Shepherd — May 11, 2011 @ 12:42 pm

  3. Hello

    This is very interesting but a few questions arise.
    The first one is about the amount of Kieselguhr that I should use for say a liter of linseed oil.
    Is there a specific measure or should I just use roughly two tablespoons per liter?
    I tried adding some but the color turned very yellow/orange and not kind of blackish as in your picture.
    Can any Kieselguhr product be used? I’ve bought it as a dietary suplement for horses as that appear to be the only type of Kieselguhr readily available where I live.

    I’m also curious about your book which appears to cover many interesting topics.
    Can I get it at an online store like Amazon.com (I’m European and thus can’t just go into the nearest local American bookstore and ask them to order it)?
    I tried searching on the title or your name as the author but nothing showed up.

    Kind regards, Mikkel

    Comment by Mikkel Christensen — July 26, 2011 @ 3:56 am

  4. Mikkel,
    Welcome, and two tablespoons per leter is about right. Try shaking it repeatedly to help the process, but it will depend on the raw linseed oil you are using, colors vary. The Kieselguhr I use is for gardens, the stuff for horses should be just fine. Colors vary from white to grey to yellow in the Kieselguhr from various sources.
    As for the book, I am just getting the ISBN set up, it will show up in Books in Print shortly. Send me an email:stephen@fullchisel.com and we can make arrangements for international shipping.


    Comment by Stephen Shepherd — July 26, 2011 @ 6:33 am

  5. Thank you for answering.
    Can you tell when it’s done by change of colors alone or do you just let it set for a fixed amount of time?
    Mine appear settled already after 24 hours with all the Kieselguhr lying at the bottom as precipitate and thus I shake it a few times a day to stir it up.
    I wonder if the Kieselguhr is suppose to dissolve completely when it’s done or if I will still have the same amount of precipitate in the end.

    I’ve just send you an e-mail regarding the book. My e-mail address is [gaarden at stenbjerglykke.dk] and please let me know if you don’t receive my e-mail at some point today since then it’s probably blocked by some kind of spamfilter 🙂


    Comment by Mikkel Christensen — July 27, 2011 @ 4:19 am

  6. Mikkel,
    I got your email. I will check into Amazon later.

    The Kieselguhr will not dissolve, it is there to act as a drier for the oil so it will percipitate out and settle on the bottom. You can decant the oil off and leave the thickness at the bottom. You can use this to make putty for filling holes.


    Comment by Stephen Shepherd — July 27, 2011 @ 6:51 am

  7. body

    Hello I recently purchased an identical table to one that was restored by Stephen and once belonged to Mormon Founder Joseph Smith. Any additional info on this table would be appreciated. Table can be seen on http://www.fullchisel.com/blog/?m=200803, Any info would be nice

    Comment by John Creech — January 1, 2012 @ 5:20 pm

  8. John,

    That table was made about 1820, perhaps a bit earlier. It was made in the midwest, cherry is the primary wood and poplar the secondary.


    Comment by Stephen Shepherd — January 3, 2012 @ 7:46 am

  9. Ciao.Io uso solo medium fatti da me,olio nero,mastice,olio siccativo Van Dyck e il gel MaROGER’S. Una domanda si puo’ usare per la pittura l’olio di lino cotto da un litro dopo averlo lavato? L’olio si chiama GALLOIL. GRAZIE.

    Comment by Salvo — August 31, 2012 @ 1:42 pm

RSS feed for comments on this post. TrackBack URL

Leave a comment

Powered by WordPress