Thanks for the overview. I agree completely with your suggestion of independent analysis. Having analysis done by a party that has a "dog in the hunt" is questionable and scientifically shaky. Like having the tobacco industry do research on the health risks of smoking.
I also agree 100% with your suggestion that beyond basic testing the person collecting the samples has to have a comprehensive understanding of where to test and what to look for. If there is no background research into the applied technology then the potential for error is great. This is where I have seen the majority of research into preservation technology fall down. Investigators have to dedicate themselves to developing a comprehensive understanding of the processes and technology involved. It appears as if few investigators are willing to take the time to develop this type of understanding leaving much of the research to "amateurs" (in the classical meaning of the word). Errors and erroneous conclusions abound. Reasearch that is assumed to be solid is accepted as fact and the problems roll on into the future.
As an academic I often find that people assume that I know more than I really do about specific technologies. Instead of faking it I always advise that a true expert needs to be consulted in most cases while I continue to expand my knowledge base. I can advise as to which path they need to take but I can't always walk the road with them.
Brian
----- Original Message -----
From: Edison Coatings <
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Date: Saturday, April 7, 2007 6:25 pm
Subject: Re: [BP] White wash 2
To:
[log in to unmask]> Brian,
>
> We should not underestimate the knowledge of Geology that
> existed in the 19th Century. Gillmore's book, detailing work
> before the Civil War, records his comments on mining operations
> from personal observations of all the major cement producers. He
> also provides recommended procedures for sampling and testing
> cement, taking random samples from various lots. I don't know
> what year the Watertown Arsenal started testing cement, but at
> some point there was testing performed and published annually.
>
> As to consistency, there were also detailed chemical analyses
> published for every cement producer. Cummings also enlightens us
> to the effect that anything negative anyone had written about
> cement consistency was invariably recycled European information,
> where the geological deposits are very different from those in
> North America, and tended to be more inconsistent. He tells us
> that while American cements had characteristics that varied from
> one producer to another, these were well-known and very
> consistent within each source. Cement specifications for
> fineness, set time, soundness and tensile strength were used by
> the Corps of Engineers, further developed in the 1870's by ASCE,
> and eventually formed the basis for the ASTM Standards.
> Municipalities, canal authorities, water authorities, railroads
> and other major cement users all had published cement
> specifications. So all this was not some haphazard, back-
> woods "Clem's backyard barbeque, whiskey still and lime kiln".
> The lime industry, by comparison, seems to have almost no
> organization or data for the 19th Century.
>
> The geological deposits currently being mined in Rosendale
> stretch more than sixty miles to Kingston, NY, and are extremely
> consistent. The same deposit has been mined since 1828. The
> Corps of Engineers specifically favored cement from Rosendale,
> NY, though natural cement was produced in at least 17 states
> including Georgia.
>
> As for local masons, I don't think that's where the testing
> would occur. The material was used on projects specified by
> engineers, and I believe Quality Control would have been handled
> between the engineer and the producer.
>
> As for choices of materials, there were certainly periods of
> overlapping, competing technologies. We know about hundreds, if
> not thousands of major buildings and structures which have been
> documented as to the materials used, but there are undoubtedly
> many times more that are not documented. Which goes back to my
> original point - you have to get a competent and honest analysis
> and let the forensic record speak for itself.
>
> Mike E
> >
> > So I assume that to make these materials the manufacturers
> would have to have a very specific understanding of the type of
> raw material needed, where to access it and and an
> indepth knowledge of the performance of each final material with
> repeated testing going on at the point of manufacture to make
> sure that the raw material being quarried and processed was
> resulting in consistent final product. I understand that a
> quarry in one town might produce one type of product with one
> type of performance capabilities yet the next village over might
> produce a similar raw material that would have completely
> different capabilities. I also assume that a wise project
> engineer on site would continue to sample the material after
> delivery to assure that he was getting a consistent product from
> the manufacturer.Without access to labs or certified product
> testing agencies I can see how this arrangement would be highly
> problematic. I imagine that in reality, the delivered product
> would have a wide range of performance capabilities and that the
> local masons would have to do the best they could with the
> material they had. Do these assumptions seem logical?
> >
> > Brian
> >
> >
> >
> >
>
>
>
> --
> To terminate puerile preservation prattling among pals and the
> uncoffee-ed, or to change your settings, go to:
> <http://listserv.icors.org/archives/bullamanka-pinheads.html>
>
>
>
Brian Scott Robinson, MHP
Professor
Savannah College of Art and Design
School of Building Arts
Historic Preservation Department
P.O. Box 3146
Savannah, GA 31402
912 525 6940 office (Tues/Thurs)
912 262 2650 home (students emergency only)
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