> Aloha!
> I have a question on lime plaster. I am restoring a building in
Hawaii
> that originally had lime plaster as an exterior wash over coral
blocks.
> The original recipe for this plaster wash recorded in archival
> materials from 1832 was: “The receipt (sic) for the cement is as
> follows: take one measure of sand, two of wood ashes, and three of
> lime. Mix them together with such a coloring as may be fancied and
let
> the materials be combined with as much oil as will allow of (sic)
the
> substance being put on with a painters brush.”  On other buildings
clay
> was added to the lime mixture. What does the wood ash do in this
> recipe? Is lime plaster being used today? Thanks!
> Spencer Leineweber
>
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>
Since I haven't seen anyone tackle this one, I'll take a stab at it.

The recipe sounds like a rudimentary paint formula. The oil cures to a
film which is harder and more weather resistant than the lime. I am
uncertain about the role of the wood ash, other than that it is a fine
filler which would change the application properties of the coating,
probably getting it to flow without too much sagging. This could have
been advantageous if the sand didn't contain very many fines. I
imagine that it is possible that there was also some interaction with
the lime as some sort of pozzolan. The clay would almost certainly
have had that effect.

Edison Coatings, Inc.
M. P. Edison
President
3 Northwest Drive
Plainville, CT 06062  USA
Phone: (860)747-2220
Fax: (860)747-2280
email: [log in to unmask]
Internet: www.edisoncoatings.com

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To terminate puerile preservation prattling among pals and the
uncoffee-ed, or to change your settings, go to:
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