RE: Gloy is NOT PVA

I believe that PVA goes "off" and grows mould unless it contains a
preservative. I seem to remember this from my days as a mother of small
kids, when we were warned at Playcentre that the preservative in PVA was
very toxic. One would imagine that the PVA ITSELF was probably not that good
either. So I'm sure that yes, it DOES need predervative. Infact, I have seen
dilute PVA which I was using for metal leafing grow mould even with
preservative.

Kate

-----Original Message-----
From: davidhatton@totalise.co.uk [mailto:davidhatton@totalise.co.uk]
Sent: Monday, 27 March 2006 12:39 a.m.
To: alt-photo-process-l@sask.usask.ca
Subject: Re: Gloy is NOT PVA

Hi Terry (and thanks to those who replied),

  It is from the horse's moth that Gloy is made up of PVA + a
> plasticiser+a preservative.
>

Personally I have a problem with horses finding them the least reliable of
creatures fit only to be rendered into glue as soon as possible. The
reason for the headline is that I have reason to believe that this is not
the case No PVA in Gloy). I'm not a chemist but why does PVA require a
preservative and a plasticiser? Is PVA not an adequate adhesive in its own
right?

The my 'research' shows Gloy as a brand to be part of the historical record
at least as early as 1918 and I suspect that PVA was not in the
mainstream of adhesive manufacture at that time. Could it be that the
current Gloy has been re-engineered in recent years with modern
components ? The original ingredients would have deteriorated without a
preservative I agree, but surely not PVA (unless the plasticiser is
corn syrup or something).

Any thoughts?

David H

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