Re: gelatin hardener (Re: APIS, hydroquinone hardening)

Ryuji,
Always interested in low toxicity stuff with students. Of course, when I
was taught gum we were using formaldehyde and glyoxal, certainly not low
toxicity stuff, so I don't suppose glut is any different. Montana in the
winter is not conducive to sizing outdoors (one of the myriad benefits of
living in South Carolina for two years).

I sized a batch of paper this past week outside with glut (hydroquinone just
came in the mail), and the other thing I like about it so much is how smooth
it is as a hardener. It almost feels acrylic-y. And it is awfully quick,
usable as soon as dry. So if you discover a hardener even better than glut
I'd sure like to be in the know.
Chris
>> BUT, presuming in a class of students where you are already teaching
>> gum printing with dichromate, the use of di and a pinch of
>> hydroquinone would seem to be less toxic than other
>> choices...perhaps.
>
> How real is this need and desire?
>
> I found a compound that can harden gelatin (and a lot of other
> polymers) very well and has manageable level of toxicity (again there
> is no such thing as a safe hardener) with practically no odor or
> volatile component. It can be used in mix-before-use style but it
> comes with a couple of obvious inconvenience factors.
>
> I'm about to test this compound for some of my emulsion projects, but
> based on the chemical properties of this compound, I'd expect the
> hardening to be fairly slow compared to glut, taking a day or two
> after coating and drying to harden, and maybe a week to reach teh
> maximum hardening effect at room temperature. This may be an advantage
> for people who size paper in a large batch, but it is definitely a
> concern for me.
>
> More info to follow when I get enough experience with it.
>
Received on Sat Jul 23 08:06:58 2005