[Cob] Alum and Soap --I'm getting picky!!

[Amanda Peck]

a) unless you're using Dr Bronner's Peppermint Soap for your dishes, (o.k., 
his almond, or lavender count too), you're probably using DETERGENT.  Even 
the Bronner Sal Suds is a detergent.  I don't know much about detergents.  
Soaps are made with a fat or oil and a strong base like lye by definition.  
And there may be a big difference between soap and detergent in the context 
of traditional waterproofing.

b) paints are forming a skin after they do dry--they're pretty waterproof on 
their own, so something trapped in them is unlikely to suds up.

c) Yes, bits of the coating ARE going to wash off, flake off, crack a bit 
when some fool decides to carve a heart in it with his initials and hers in 
it.  To some extent, all surface coverings--from oil-based paints or your 
acrylics on down to lime plasters (not to mention the brake discs on your 
car!)--are what are known as "sacrificial coatings."  That is, things that 
are intended to wear, wash, oxidise, etc. and be renewed every so often.  
Leaving treasured paintings out in the sun--even in direct sunlight in a 
building--not recommended.   Even cave paintings are not immune--the famous 
French ones are now mostly viewable in virtual reality because there was so 
much deterioration from all the people wandering through.

...............

Kathy wrote:
Uh, no, I don't think so.  I use regular ol' liquid dish soap in my
acrylic water based paints (to extend drying time) and none of it
has ever "re-suds up".

 > Ingestion of 30 grams (1 ounce) has killed adults. Huh. And you
find it right next to the allspice.

Well, I would hope no one would take a bite out of my cob bench -
lol!  But the point about folks being sensitive to alum (eyes skin,
etc.) would likely be a problem on a bench where skin would come in
contact with it....

BUT I was reading earlier today about a patent that was obtained by
a fella back as early as 1876 (for a mixture that included alum that
was put on canvas tents and uniforms to waterproof and prevent mildew
& mold) and there were reports even way back then that the fabric
treated with this stuff did irritate the hands/skin of some soldiers...
however, the pertinent point was that the fabric didn't irritate anyone
until they went to cut the fabric when mending, etc.  So, perhaps the
alum/soap mixture on a cob bench would NOT irritate anybody as long as
it was properly maintained and not allowed to dry/crack/flake, etc.

Kathy

_______________________________________________
Coblist mailing list
Coblist at deatech.com
http://www.deatech.com/mailman/listinfo/coblist

_________________________________________________________________
Get ready for school! Find articles, homework help and more in the Back to 
School Guide! http://special.msn.com/network/04backtoschool.armx