Cob Is Linseed Oil All You Really Need? - Exp. 2

[brad davis]

Harry, John, Bill, and others, Thanks again for the caveats of good
information and comments. Good information will help answer the ultimate
question: Is Linseedoil All You Really Need? 

Repeats

It is always a good thing to repeat all or parts of experiments to check for
consistant results. Classification charts and data tables could be made
available once results become established.

Rain

Rainfall needs to be measured for now on and the submerged samples should be
in collected rainwater. Temperature and general weather conditions should be
observed daily.

Lime & Linseed Oil

I am naturally always thinking about Experiment 2. Obviously, what worked
best in Experiment 1 will get priority.

It interesting to hear that linseed oil applied to Lime, works better after
the Lime has taken some time to react. I will apply the oil at different
time periods in accordance with the recommendations given below by Harry and
John. 

Harry

Snip

"On lime mixes, I would recommend coating the lime/sand mix after it is almost
hard - "thumb print hard" - then rubbing in the oil. This is what McDonald
describes in "the History of Plaster" as being able to make lime /sand plaster
hard and polished as marble."

John

Snip

"Linseed oil should not be applied to fresh lime-cement plasters because 
their initial alkalinity is to high.  The linseed should be added after 
about one year if possible.  The application to dry clay is probably OK, 
and your results are very encouraging."

The Linseed Oil/Lime Series 

1.  Oil rubbed into 2 sand/1 lime when the plaster is " thumb print hard."  

2.  Sample will be 2 sand/1 lime with oil rubbed in "one year if possible."

3.  Sample will be Cob with Linseed Oil rubbed in (Exp.1) then sand/lime
applied.


   Do you guys think I need to wait for awhile to apply the sand/lime after
the    application of Linseed Oil(3)?


4. Combinations of: 1&2, 3&1, 3&2.


Tests in Experiment 2 will also include other oils, soaps, etc.


US/ICOMOS Newsletter No. 6 (1995)

In this newsletter there is a section titled "Using Chemicals To Save
Adobe." by Charles Selwitz, Getty Conservation Institute. 

The article states that there are three methods used to treat adobe.

1. Consolidation which is the process where a suitable, reactive chemical in
liquid form is allowed to soak into porous stone or adobe where it sets up
and hardens so that the adobe is no longer turned to mud when in contact
with water. The Institute used a product called Stone Strenghener for
consolidation. My guess is Linseed Oil is a consolidator but I am probably
wrong.

2. Substituting some of the water that is mixed in the sand and clay with an
emulsion acrylic polymer in water.

3. Surface treatment with a water repellent. Typically, the
polymethylhydrosiloxanes are used. Apparently when the hydrosiloxane
contacts clay, bonding occurs between the polymer and adobe to provide for
exceptional stability. El Ray Adobe Protector is a polymethylhydrosiloxane.
I was thinking of testing this product. It is expensive but it would be
interesting to see how it measures up to Linseed Oil and the like.


Thoughts and Comments Welcome.


Bye for Now.


Brad