On 3/2/2010 8:24 PM, [log in to unmask] wrote:
> I would say that the modern 4' lengths of cornice tend to be made of 
> fiberglass or precast, and the relatively short length is also easier 
> to fabricate as well as to handle.  Old cornices made of wood or sheet 
> metal could be longer runs, but TC cornices are likely to be made up 
> of sections about 2' long.
ah, yes, we were forgetting terra cotta cornices, and though one would 
think that the pieces wld be like 24" or very close they seem to vary 
all over the place within 1/4" to 3/8" of an inch with a mortar joint of 
varied width

we measured exactly a hundred or so pieces on one school in Brooklyn and 
the variations in dimensions, and the means by which the original 
mason's made up for the variations, leastways as far as we could tell, 
were interestingly revealing

when tc is set original the mason's seem to have tended to set the 
pieces as they were and to adjust with the joint width until they got to 
a situation where it would not work and then they trimmed... and a lot 
of field trimming was done rough

I doubt it occurred to them, and if it did not for very long would it be 
on their mind that anyone would come along and try to replicate their work

when after-market we come back and try to fit into the existing it is a 
more difficult process to deal w/ manufacturing tolerances, and to get 
the new piece to fit into the hole -- takes longer, likely w/ adjusted 
money value it also costs more per unit to set than the original

terra cotta clay shrinks in the process of making the units and thus one 
needs to take the measure of the hole in two dimensions, then have a 
real good idea how much the unit will shrink and hope to hell when it 
gets on site that it will actually fit (more curious if the pieces are 
coming from the UK where they measure in metric to the US)

if it does not fit, and needs to be field trimmed (fortunate that it is 
easier to field trim these days w/ diamond blades etc than in the 
original days w/ a hammer & chisel) and if it is glazed then there is 
the likely long-winded discussions about voiding the integrity of the 
glaze on the cut edge

good to have those epiphany experiences prior to the crew of mechanics 
standing on the scaffold waiting to get a move on

][<

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