When mixing curing agents, the dosage calculation can be referred to as follows:   1. Firstly, calculate the active hydrogen equivalent X of the curing agent mix: Assuming that two curing agents, A and B, are used, and that the proportion of curing agent A in the mix is a per cent, and the proportion of curing agent B in the mix is b%  The proportion of curing agent A in the curing agent mix is a%, the proportion of curing agent B in the curing agent mix is b% a% of curing agent A / active hydrogen equivalent of curing agent A + b% of curing agent B / active hydrogen equivalent of curing agent B = 100/X; e.g.: If: 60% D-230 (AHEW=~60) mixed with 40% IPDA (AHEW=~42) is to be used in the curing agent mix. The active hydrogen equivalent of the mixed curing agent is calculated as: 60/60 + 40/42 = 100/X, X = 51.28 This results in an active hydrogen equivalent of 51.28 for our curing agent mix.   2. Calculate the amount of mixed curing agent to be used for 100 grams of E-51 Bisphenol A epoxy resin according to the formula for the amount of amine curing agent: w (mixed curing agent) % = 51.28/186 ✕ 100=~27.6 That is, for every 100 grams of E-51 BPA epoxy resin epoxy resin to use about 27.6 grams of mixed curing agent.