There is no reason to use flour as an adhesive in papier mache unless you specifically want to include it.

Flour really has only two benefits: it's cheap and it's non-toxic. This makes it an adequate adhesive for small children, and if they eat it, no harm is done.

It also has some negative qualities: it can attract insects and rodents, as it is a grain product. It MUST be sealed against moisture. And once mixed, it has a short life before it molds, so if you use it, make small batches. You may be able to refrigerate it for as long as a week, but why bother?

Personally, I don't use it anymore, by itself or with anything else.

Sue

Also, flour can become brittle and absorbs moisture readily.  The best paste (in my opinion) is methyl cellulose.  It is used in wallpaper paste but pesticides and sometimes insecticides are added so if you can get the pure stuff - which comes in a very fine powder - that would be best.
Mixed with about 25% volume of PVA, it makes a wonderful paste for both laminating and pulping.
DavidO

Hi David:

Now I've understood your message and I have to say:

01-I'm not sure where I can find (if I can) methyl cellulose here in Brazil. Where do you find there?

02-Could you please explain what does "wallpaper paste" mean? It was not possible to me to find the definition in portuguese. I have seen this word many times but I couldn't understand.

Thank you for your attention.

Shali

Fantastic Sue!!! Really. Thank you. It's totaly understandble.
Now it's ok. ;-)))))))))

Have a nice weekend.
Shali