Re: ferri sesquichlorati

[Kees Brandenburg <ctb@zeelandnet.nl>]

On 22-okt-06, at 16:06, Halvor Bjørngård wrote:
> BTW, Is there a maximum number of layers for gum, one book I have claim
> twelve or so, but have seen other claims of 20 .. ?
Hi Halvor,

The maximum number of layers is related to the strenght of the (rigid) 
package of gumlayers and the constantly expanding and shrinking paper 
fibers between wet and dry. I think 20 layersare way too much and only 
possible on a rigid (non paper) surface or on a paper that is made 
rigid by fixing it on a rigid surface.

My still workable (= near maximum) number of layers is 6 or maybe 7, 
but I try to do with less.

I also am very much interested in the 'ferric' hardening of gum 
especially from a environmental viewpoint. I'll do some experimenting 
too!

-kees