>I would be most interested in your source for
>all this?
>
>It flys in the face of what every stonemason,
>plaster mason, and brick mason has been doing in
>USA, Canada and the UK for the past 200 years. I
>work with restoration masons all the time.

Gary you miss my point again - i do not argue with you about masons using materials they use. I am talking about painting on the materials they use and serfaces those materials give...

We have experimented with silica (sandblast) sand - easily found and clean.

1) mix is rather watery then "fat"
2) layers (arriccio + intonaco) do not stick as well as in other sands.
3) plaster sets (stops accepting paint) faster causing latter layers "slide" and not to stick.
Pouzzoli Red is one of the picments used in fresco for its color advised NOT to be painted over with other colors because it locks the plaster.

here is what I remember from other resources i read in relation to silica - you perhaps can clue me in it better since it is about plastering - hydrated lime is what we need to use for fresco, "hydrolic lime" is what is quite good for plasterers because it is like cement (will set under water) some of the people I know also say that dolomitic (high magnesium) lime putty will set under water when mixed with silica or even other sands.

from italian book - add a little terracota since it has clay which has for the plaster to set faster.

>How can an inert substance like 'glass' speed up
>the 'cure' -absorbing Carbon Dioxide - of lime?
>
>What possible difference can less than 1%
>magnesium oxide cause? If it is higher - it can
>form into tiny little chunks - but not a problem
>with air classified lime - and also pockets of
>high concentration could cause different 'freeze
>thaw' - only a problem if your fresco is going
>outside in freezing wet weather.

I never said less than 1% 90-95% of calsium is a realistic number.

>I would be interested in seeing a chemical data
>sheet on your lime before I ordered any - is
>this available?

no datasheet is not available - only about 7 years of using it...