Cob Re: Adobe Sealants

[Mike Carter]

-----Original Message-----
From: Vernon B. Johnston <vajohnston at nas.com>
To: coblist at deatech.com <coblist at deatech.com>
Date: Saturday, December 06, 1997 5:52 PM
Subject: Re: Cob Yoda's cob house


>Mike wrote:
>
>Carole Crews (sp?) in New Mexico has a hybrid cob/adobe structure with an
adobe dome roof (not catenary).  She has  suggested a   special sealant
(silica-based) that waterproofs but still allows water vapor to enter/exit
the material.
>
[snip]  My question is do you have any further information on
>the Carol Crews' special sealant?
>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>
Finally found my notes on this.
The substance is called "9400" from Palmer Industries.  A couple of years
ago it was around $20/gallon.  I think Palmer Industries is the one in
Frederick, MD (301-898-7848), but not sure.  Also was available in 5 gallon
size (much cheaper/gallon).

The page below has a lot of concise information on preservation
of adobe, including how polymethylhydrosiloxanes work (they sound more
benign than the name might imply).  It mentions several other products for
various purposes.
http://www.icomos.org/usicomos/news/usicomos695.html#3

More general information and manufacturer's addresses can be
found at: http://www.greenbuilder.com/Sourcebook/FinishesAdhesives.html