linseed oil varieties

[Kyle Kraft]

I'm new to the use of linseed oil for wood finishing. Could someone explain the difference, if any, and the use of the following...linseed oil, boiled linseed oil, and polymerized linseed oil, et.al.??

[John Kain]

Great question. I'll second that question. I was at our local paint store jsut yesterday wondering about boiled vs "un"boiled.

[Howard Acheson]

Linseed oil is the oil from flax seed.

Raw linseed oil is just that. It's as it comes out of the pressing of the seeds. It dries very, very slowly taking 2-4 weeks to polymerise or "cure".

Boiled linseed oil used to be heated to begin the polymerization process so it dried or cured within a few days. Today, metal dries are added to cause faster drying.

Polymerized linseed oil is linseed oil heated in the absense of oxygen to turn it into a heavier, thicker partially polymerise or cured oil. It dries within a couple of days and leaves a slilghtly more durable and watervapor resistant finish.

All in all, no version of linseed oil is a very good finish from a water and water resistant or durability point of view.

True, real, 100% tung oil is the oil from chinese tung tree. It is somewhat lighter in color than linseed oil and is slightly more water resistant. But it is also a very long drying oil. It can be polymerized to make it cure faster but tends to be very expensive. Like linseed oil, it is not a very durable or water resistant finish. It's primary use is in marine finishes where it is substituted for linseed or other semi-drying oils for making varnish.

Beware of products labeled "Tung Oil Finishes". These are not true tung oil--in fact, most have no real tung oil at all.

[Kyle Kraft]

Thank you for the reply, funny how a dietary supplement (flaxseed oil) with a little chemistry and some heat can also make a nice furniture finish!