Cob: Re: Earthen Floors

[SANCO Enterprises <Paul & Mary Salas>]

List Members,

This is a response I forwarded to Rob and felt that it may help others.

Robert Bolman wrote:

> Today I made six earthen floor samples.
> Each sample is 8" x 12" x 1.5" thick.
> My goal is to determine which of the non-linseed vegatable oils
performs
> best.

Robert, what you seek are slow setting oils with unsaturated fatty
acid.  When
used as a drying oil for earthen floors, the oil must contain
linolenic,
linoleic, eicosapentanoic, etc.  Unfortunately, linseed oil is at the
top of the
list followed by less desirable candidates such as safflower, fish,
soybean,
tall, tung, castor and oiticica


Linseed oil is the first choice drying oil for use in the earthen floor
applications due to its high levels of unsaturation (IV=155-205),
especially of
linolenic acid which generally exceeds 55% by weight. Soybean oil and
safflower
oil are two other candidates. However, they are generally considered
less
desirable because they have less total unsaturation with most of the
unsaturated
fatty acids in these oils being linoleic (IV=120-141 and 145
respectively).

These oils are used because they do not fully harden and remain
flexible.
Alcohol or mineral oils are used as a vehicle to penetrate the earthen
floor and
assist in providing water absorption resistance to the areas
penetrated.  The
depth of penetration will be dependent on the density of the earthen
floor and
capillary action provided by organic matter contained within the mix.

There are floor sealers made from linseed oil that have been
polymerized.  The
same polymer reaction with linseed oil is used in the adhesive used for
OSB
panels and other ag type materials.  The major polymer producer is
Arthur Daniels Midland.

Hope this helped clear up some the questions raised and perhaps speed up
your
testing process.  Be sure that your test coupons are absolutely dry,
>4%  moisture
content.


Paul Salas
SANCO Enterprises, LLC
Rio Rancho, NM