Quote Originally Posted by geyes30 View Post
Hi Ian,

Thanks for your response. My follow-up question is, Why is the hardening agent not of the more common potassium/sodium alum form (i.e. potassium/sodium aluminium sulfate)? Do the components listed allow the formation of the more common alum form in the solution?
Alum is Potassium Aluminum Sulfate.

http://en.wikipedia.org/wiki/Alum

The hardening action of Alum is reversible.

PE