Borax Raku Glaze - Can You Wait To Fire?

[zenka]

I have read that it is bad to mix ahead borax based raku glases because they can undergo a state change with water.  Is the reason because it will be hard to apply the second time after time has passed or is it because it will make the glaze look different after firing? 

 

I want to mix, then apply immediately, then I won't be firing for another month. I want to know if this wait to fire is going to be a problem. 

 

Any help would be much appreciated. 

 

 

"because water dissolves borax decahydrate, boracic acid, and soda ash when the glaze is first mixed, it is best to fresh-mix these recipes just before application to the biscuit. Otherwise, on standing for a week or more, some sodium borate (borax) and/or sodium carbonate (soda ash) may come out of solution as rather large crystals making the glaze dispersion non-uniform.

 

Also, if the recipe calls for Borax (hydrated sodium borate), the amount of boron oxide actually contributed to the mix could vary even further. The common form of borax, the one used mostly for washing clothes, has a chemical formula of Na2O.2B2O3.10H2O (sodium borate decahydrate). This material, if left standing about, will gain or lose moisture (H2O), hence, will undergo a change in "formula" weight and the crystal shape may also change to another form.

 

https://digitalfire.com/4sight/education/first_you_see_it_then_you_dont_raku_glaze_stability_113.html