Message text written by "BP - \"where heavy conservationists hang out\""
>
Jahn does not shrink. <

Let me put this response as professionally as possible.

Jahn DOES shrink, it shrinks alot. Depending on which lab study you look
at, it shrinks as much as 0.11% which is considered "High" shrinkage under
ICRI guideline 03733. For years Jahn advertising has called the product
"shrinkproof", which is an undefined term with no specific technical
meaning. We need to use techmical language which is specific and
unambiguous, or we create confusion instead of communicating ideas and
promoting understanding.

Unfortunately the preservation industry has not managed to assemble the
sort of consensus building task forces we require to create objective
guidelines for things like patching compound shrinkage, bond strength,
mechanical compatibility, permeability, etc. and in this respect HP is far
behind the concrete repair industry.

If we're going to make product performance claims, we need to have numbers,
methods and consensus as to what's most important. Shrinkproof indeed!

Mike Edison
Edison Coatings, Inc.