-- I am ready to do interior plaster with kaolin with fine sand and wheat paste. does that sound like a good mix to you? ___Judith
HI, yes your recipe is traditional, wheat paste is used by many of the cob and earth people. some will only use 'organic' unbleached wheat flour, other than the cheaper wheat flour. both work.
regular earth-mined Kaolin is a very very fine powdery clay, used in making china and dishware, and you do not need to add lime if you don't want to. ( Sacramento CA is a big site for mining this clay) going from an inert clay plaster to using a lime plaster means more work, skin protection, etc. You can use bare hands with clay and paste. any any lime plaster must have a sand mixed it, it needs sand, or marble dust, and fine fibers will keep it from cracking. fine chopped straw is used in clay plaster, or nylon fibers -Nycon is a brand
any clay is a pozzolan when added to lime, ( word comes from the town in Italy Pozzolli ..but it refers to the volcanic ash clay found there. but that's not what is important for this use.
Most people can't get coal fired ash, or silica fume metakaolin type products for small DIY projects.
in a wet bath/kitchen don't use straight drywall compound. there you can use your clay + other ingredients only plaster. clay is water loving -hygroscopic- and will hold then releaqse moisture, where drywall compound will not.
PLEASE START A NEW EMAIL TO REPLY, auto replying to this clumps the big email over and over in all replies, wastes file space, slows readers with slower connections.
Charmaine
Charmaine Taylor/Publishing & Elk River Press
PO Box 375 Cutten CA 95534
www.papercrete.com
1
POZZOLANIC (FLY ASH BASED) MORTARS AND
STUCCOS
History
The Egyptians learned to burn gypsum, and the Greeks learned to burn lime. The
Romans learned to combine burned lime with other products to make concrete and mortar. Although some modern experts may not want to admit it, the Romans made mortar andconcrete without portland cement. They used broken brick and tile that they had crushed, as well as sand and gravel, and mixed them with burned lime and volcanic ash. An important and high-quality
source of volcanic ash came from near Pozzoli, Italy, and thus was called pozzolan.
The Pantheon, probably the best-preserved building of the Roman Empire, was rebuilt in Rome in 200 AD using pozzolanic concrete and pozzolanic mortar and brick. The dome with a span of 142.5 feet was built with lightweight pozzolanic concrete consisting of pozzolan, lime, an pumice. The Romans carried their technology throughout their empire. There are many other
structures built by the Romans with pozzolanic cements and mortar that are still in use today.
Pozzolans are the ancient equivalent of fly ash from a coal-burning power plant.
As centuries passed, the use of pozzolanic concrete and mortars faded from prominence in Western Europe
A pozzolan is a substance that is not cement in itself, but when mixed with lime and water will develop cement-like properties. The basic technology consists of mixing a pozzolan with lime and water.
Dr. Davis, at the University of California in Berkeley, in the 1940s and 1950s was
instrumental in getting the Bureau of Reclamation to use pozzolans in large dam projects. His first success was Falcon Dam (1953) on the Texas-Mexico border about 140 miles upriver from Brownsville. For that project a deposit of volcanic ash was mined and processed.
Since that time, much work has been done with pozzolans in concrete. Much less work has been done with mortars and stuccos. Silica fume, metakaolin, some diatomites, and most volcanic ashes are pozzolans. These are
often classified as Class N pozzolans. Silica fume and metakaolin are often referred to as super pozzolans since they are usually finer than other pozzolans and thus more reactive.
Remember, for every building in the United States that has portland-lime mortar that is over 150 years old, there is a building in Italy that has pozzolanic mortar that is over 1,800 years old. (shortened for focus)
by Herb Nordmeyer, ISG resources
Friday, September 7, 2012
[papercreters] Judith's wall plaster
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