What is the generic equivalent of "Davelastic" admixture?

Greetings Oh Tiler-types...

I'll be doing a couple of Shower-Bases soon using Davco SE-7 adhesive, into which Davco recommend that I add some of their "Davelastic" admixture. The only thing is - at the required mixing ratio of 50:50 with water, it's as dear as hell to use. I can't quite remember the exact cost of the stuff, but it opened my eyes a fair bit when I saw it on the shelf at the BigB. Finding a cheaper generic equivalent (sort-of in the fashion of using just plain old PVA and water instead of their pre-watered-down "Ultraprime") would be a very handy thing...:rolleyes:

Davco themselves describe Davelastic as "a flexible acrylic polymer additive", and whilst its MSDS gives nothing away whatsoever with regard to its chemical composition, it does at least state that it has a "mild ammonia odour" - which I would have thought was not quite typical of normal PVA's. Anyway, it can't be just a straight-out normal PVA, because they tend to break-down under prolonged exposure to moisture - ie. the type of environment which Davelastic is generally aimed at...

A further clue to its composition, however, is tucked away up in the right hand corner of their "Adhesive Selection Guide", where they indicate that it is adequately substituted by another non-Davco-branded product called "Bondrite" (but which they probably make anyway...). There is little information available on the net about Bondrite, other than that it is a "bonding and sealing agent PVA". So - Is Davelastic simply an exterior-grade water-resistant PVA?...

Okay - Final "Punchcard" for your assorted Cortexi: Bondall make an also-very-expensive admixture called "Hydrocrete", which is also mixed 50:50 with water for use in wet-area tiling. Sounds similar in concept to Davelastic, but the only clue they give to its composition is that it "contains a styrene-butadiene latex to provide excellent adhesion". Does this mean anything to the more "chemically-aware" among you?..:?

So - the only cheaper but still adequate substitute might end up being Exterior-Grade PVA - which is still expensive anyway ( :( ), but I'd be very interested to hear your thoughts all the same...

Many Thanks,
Batpig.


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