In a message dated 6/8/99 10:03:37 PM Eastern Daylight Time, [log in to unmask]
writes:

> It's possible your problem is quarry sap, if the stone is new.  On the other
>  hand, the mason foreman working on the NYAC told me the other day that ya
>  gotta be real careful setting/pointing LS. Ya set it in (regular) mortar
and
>  point it with a very dry mix, otherwise you get discoloration of the mortar
>  at the edge of the joint (I don't remember that it was orange though, or
> that
>  quarry sap was orange either); the mason claims the LS "drinks" water.

Ralph,

We are working with repointing old stonework. The geologist encountered
recently at Yale said quarry sap is buncum. Unfortunately he has gone to
Australia and I cannot ask him about iron in limestone. Not sure what to make
of that statement. As to pointing the limestone I agree you should use a dry
mix. The discoloration would not be orange, as much as the white haze you get
from wet mortar moving into the limestone from capillary action. You also
have the problem of smearing wet cement & like over the face of the stone...
difficult to clean up afterwards.

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