Will epoxy ultimately cure even if you do not have the optimum 50/50 ratio?

Will it act as polyester resins act, with less of its catalyst and just take longer. I realize they are two totally different type reactions, but this has never happened to me before, I ran out of what I guess would be part "B" so I was wondering if anyone has "experimented" either intentionally or accidentally and knows if the "less than optimum" ratio will cure over time