Full Chisel Blog

June 22, 2010

Raw Linseed Oil

Filed under: Finishing,Historical Material,Of Interest,Uncategorized — Stephen Shepherd @ 7:18 pm

Apparently it doesn’t take much to make me happy and finding this locally sure did.  Boiled Linseed Oil [BLO] is easy to find and is ‘chemically boiled’ with the addition of metallic dryers to make the raw linseed oil, boiled linseed oil.  I don’t know what the chemicals are and they won’t tell me.  There use to be a law on the books that stated that in order to be called ‘boiled linseed oil’ it had to be heated to 225 degrees [F].  ‘Section 1 of Chapter 412 of the law relating to linseed- or flaxseed-oil prohibits the manufacture or sale as boiled linseed-oil of oil which has not been heated to 225° F’.  Although there was no way to tell if it was truly ‘kettle boiled’ [actually heated to that temperature and allowed to cool] or ‘bung hole oil’ which is raw linseed oil with chemical/metallic driers added.

Now I have the raw ingredients and can now try the many different methods I have ran across in my research for my up coming book on nineteenth century Woodworking Finishes [tentatively titled Shellac, Linseed Oil & Paint].  I have one recipe for making boiled linseed oil by adding the juice of garlic.  There is also a method of making ‘blown oil’ a process I find interesting.  I have some food grade flax seed oil [same thing as raw linseed oil in an edible version] that I have done some experimentation with and am happy with the results, but I wanted to try using readily available raw linseed oil.  Let me tell you that it is not easy to find but my local Ace Hardware carries the stuff, they also sell Franklin/Titebond Liquid Hide Glue!  I am also going to try their Ace Spar Varnish, a non urethane varnish that is half the price of McCloskey’s Marine Spar Varnish.

There are no warnings on this can except for the spontaneous combustion hazard and not to take internally but there are no poison warnings, so I am happy to use this stuff.  It says it takes from 2 to 4 days to dry, I will have to give that a test but for many applications including varnish a slower drying time is desired.  I know that that flies in the face of modern convention but in the nineteenth century a slower drying varnish is desired.  It flows out better and according to sources produces a much finer varnish finish. 

This should be fun and I will begin playing with this stuff when I return from Las Vegas.



  1. Hi Stephen,

    Have you used “Tried and True” linseed oil? The recipe is from a nineteenth century source. I’ve used it quite a bit on furniture and cabinetry. It smells and feels good and is non-toxic. It’s not a soaking consistency, though, and you have to apply ultra thin coats.

    Comment by Tico Vogt — June 23, 2010 @ 4:39 am

  2. Hi Stephen,

    I did some poking around on MSDSs and food grade standards. Chemically boiled linseed oil that contains additives that would have to be reported on the MSDS under the Toxic Substances Control Act. Startex Boiled Linseed Oil is in compliance with the Toxic Substances Control Act and lists no TSCA chemicals in that section of the MSDS. It looks like Startex Boiled Linseed Oil is, well, boiled.


    Comment by Michael — June 23, 2010 @ 9:49 pm

  3. Loving your blogs on varnishes etc. In the UK we do not use raw linseed oils that come from hardware stores for anything that come in contact with food, if it dries within a week we reckon that it must have chemical driers in, again hard to find out.
    There are now a few suppliers of raw food grade linseed oil over this side of the pond, and if we can not get hold of these we pop down to the agricultural stores or horse shops and buy raw animal grade linseed oil in anything from pints upwards. Animal grade oils as we are concerned are fine for bowls and other items that are used with foods.
    I am still trying to get my linseed oils to dry quicker than a couple of months or more. I keep a fat fryer full of oil that when heated my bowls and spoons are dipped into. I have not yet found the oil dries any quicker after this oil is heated up to 200 c . I have not tried the sun soaked method yet.

    Comment by Sean Hellman — June 24, 2010 @ 11:09 am

  4. Tico,

    I will make sure I try some Tried and True.


    I checked out a number of MSDS for raw linseed oil and you are right many of them have no toxic warnings. I just re-read your post and I did not look at the safety sheets for boiled linseed oil, but I will do so shortly.


    I usually use walnut oil on any items that come in contact with food. Although the raw linseed oil from health food stores I have used. I tried the local agricultural/farm store but they don’t carry it anymore. Applying hot oil does contribute to faster drying time. But sometimes a slower drying time is good as well.


    Comment by Stephen Shepherd — July 1, 2010 @ 9:04 pm

  5. Just a note on ‘boiled’ linseed oil, this is really a bit of a misnomer as it is produced by blowing/bubbling hot air through the oil. This speeds up the drying time.
    Here in the UK raw, food/animal grade linseed oil is readily available and the best way to source it is Amazon and beware, there is a big difference in prices between suppliers for the same product.

    Comment by Stuart — June 22, 2013 @ 11:10 am

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