[Cob] Re: linseed oil floors/tubs

[Barbara Roemer]

For what it's worth, probably most folks' understanding of diluting linseed
oil with successively more mineral spirits (or less according to some
models) probably came from Bill and Athena Steen's Earthen Floors book.
They are in the process of rewriting that book and no longer dilute the oil,
but apply it warm, full-strength, until it no longer soaks into the surface.
Bill has said he wishes he could suck in all the copies of that booklet
since his experience has now led to so many revisions.  The new version
should be out this year.

I used three coats of the full-concentration method both with Hard Oil #9
(BioShield) and boiled linseed oil on my floor.  It needs to be reapplied at
least once/year (but my floor is only two years old, and perhaps it will
reach a "saturation point" in future years) or the floor looks dry and water
doesn't bead up on it as well.  It is quite water resistant, but I agree
with Ocean that water sitting on the surface will eventually soak in. I also
used about a gallon of linseed oil to 15 gals of floor mix in the mixer.  It
blended in fine and probably gave some water resistance, but it can't be
much (see Shannon's post on clay in water) because the oil still wasn't very
concentrated.  When it's applied to the surface, it soaks in only a short
ways - little more than 1/8th inch, so that top layer is well-saturated with
oil.  Nonetheless, the sand provides plenty of spaces/pathways for the water
to take which aren't necessarily all bound up with oil.


Barbara