I am wondering if anyone uses air slaked limes, whether for fresco, stucco, or whatever. If so, what properties do they have compared to putties?

"Air-slaked lime is concidered an undesirable commodity; it certainly is an undesirable impurity, when mixed with quick or slaked lime. Yet air-slaked lime, when separated from unslaked particles, has been made into mortar and used as such, giving a strong and durable mass." - lime stone resources and the lime industry in Ohio, by Edward Orton, Samuel Peppel

in short - you can use it but it would have limitations which will affect your painting. you may be ok with it mabe not - depends in what you do, you will have to experiment, but you will never know what is the difference unles you will experiment with both - slaked and air-slaked.

The problem with airslaked or any dryform lime (like hydrolic type s lime from home depot) aside from possible high magnesium content (type - S) it is also continue to "air-slake" in the package slowly turning into a "bag of powdered stone" and unless you get it right off the shoot at the quarry and mix with water rightaway.

Thank you for the info.
Based on the little bit of info I have, my intention was to simply leave some lump quicklime exposed to the air for a while and see what properties it has. I hope to make a trip to the kilns this spring.

>Thank you for the info.
>Based on the little bit of info I have, my
>intention was to simply leave some lump
>quicklime exposed to the air for a while and see
>what properties it has. I hope to make a trip
>to the kilns this spring.

why would you want to do that?
why not simply add water (slake it) screen it and use?
if your quicklime is pure and clean you can even use it on the same day - they still do that way in Romania...

I will water slake plenty (although I usually prefer to use pulverised for that since it I can avoid screening.) However, I have read other recipes involving air slaked lime for stucco. Millar mentions three distinct methods for slaking limes:(1) sprinkling with water, (2) immersion in water, and (3) allowing the lime to absorb the moisture of the atmosphere. I have never done nor do I have any knowledge of 1 or 3, hence that is why I would do as I said.