Full Chisel Blog

April 6, 2011

How to ‘boil’ raw linseed oil with Garlic

I am not making this stuff up.  I was impressed with the use of garlic to make hide glue stick to smooth surfaces, I covered this in Hide Glue – Historical & Practical Applications.  While researching the Shellac, Linseed Oil & Paint, I came across the use of garlic and here is just one of those fun things you can do with garlic.  This technique dates from well before 1800.

Raw linseed oil takes a long time to dry [two to four days] according to the label, so it is common to boil linseed oil to a temperature of around 225° F, or to add chemical driers to the raw linseed oil to chemically ‘boil’.  Well there is yet another way and that is to add fresh crushed garlic to raw linseed oil.

While it starts out clear after one day it turned cloudy.  Below is a picture showing three different stages, on the left is raw linseed oil [this is becoming sun thickened linseed oil] then the garlic in raw linseed oil and on the right is the linseed oil that I washed [previous post].  The garlic does lighten the color of raw linseed oil after one day.

Now the washing process that I discussed earlier did remove a great deal of the odor of the raw linseed oil.  With this stuff you can not smell the raw linseed oil at all.

While it was a bit turbid yesterday when I took this photograph, today it is a bit clearer and I will put it in a balneum mariæ with the lid removed to drive off any water and other volatiles.

Stephen

11 Comments »

  1. I should add don’t put this on your salad or pasta. This is for woodworking NOT EATING.

    Stephen

    Comment by Stephen Shepherd — April 6, 2011 @ 8:59 am

  2. Here is the oil after it spent 20 minutes in a hot water bath.

    linseed oil / garlic clarified

    Stephen

    Comment by Stephen Shepherd — April 6, 2011 @ 1:55 pm

  3. Hi, Stephen,

    Let me get this straight. First sun thickening, then garlic, then washing, then drying to get the oil shown in your last picture?

    Jerome

    Comment by Jerome Weijers — April 7, 2011 @ 8:54 am

  4. Jerome,

    Sorry for the confusion, I showed the sun thickened oil for its color compared to the garlic ‘boiled’ oil, compared to the washed linseed oil.

    This last picture is how it [garlic boiled] looked after I put it in a hot water bath and drove off any remaining water.

    Stephen

    Comment by Stephen Shepherd — April 7, 2011 @ 9:27 am

  5. Fascinating. How much would you estimate the garlic shortens the dry time?

    Peace,
    Harlan Barnhart

    Comment by Harlan Barnhart — April 7, 2011 @ 5:28 pm

  6. Any idea of the chemistry behind this process?

    Gary

    Comment by Gary Roberts — April 8, 2011 @ 11:56 am

  7. Harlan,

    I have not done any tests on anything besides the washed linseed oil, which dries like it was boiled in 24 hours. I will do some glass smear and curly maple samples of all of these different ‘boiled’ oils.

    Gary,

    I think it is more of the alchemistry involved. I would suspect that the garlic also strips out the water soluble fatty acids present in raw linseed [flaxseed] oil that slows the drying, causes wrinkling and yellowing. It could be lonely carbon atoms, available hydroxyl groups or perhaps some mysterious cross-link?

    Stephen

    Comment by Stephen Shepherd — April 10, 2011 @ 5:23 pm

  8. Stephen,

    I love your site! Thank you so much for posting such interesting and useful information. Do you wash the linseed oil after the garlic process? How long should the garlic be in the oil? When is your book to be published? I would very much like to buy a copy!

    Chris

    Comment by Chris Eisenman — April 24, 2011 @ 3:14 pm

  9. Chris,

    Welcome and I left the garlic in for a couple of days then strained it out. It has a persistent odor and I vent the jar every day. It is not washed and I have not tested it yet. I will post here when the book is available.

    Stephen

    Comment by Stephen Shepherd — April 24, 2011 @ 4:46 pm

  10. not bad , the chemistry of garlic in linseed oil is fasinating , try slicing the garlic and waiting a few minuites till the aromatics create chemical changes then add your linseed oil , you may find this improves the linseed oil after a week or so . you dont even have to cook it .

    Comment by victor alosi — July 16, 2011 @ 7:49 am

  11. It always interests me to see the many uses of linseed, and it’s great to see a practice with historical value at work too. Marvelous stuff Stephen.

    Comment by Durwin @Highbarn — March 11, 2012 @ 7:46 am

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