To determine the crosslinking kinetics of our photocurable elastomers and evaluate their suitability for SLA printing, we monitor their shear moduli during exposure to UV at an irradiance of 17 mW/cm 2 , adjusted as close as possible to the 15 mW/cm 2 irradiance used in SLA printing . We use a plate-plate geometry with a gap of 100 𝜇m, the same as the thickness of each layer during SLA printing. The gelation time, 𝑡 𝑔 , is defined as the time beyond which the storage modulus G' becomes larger than loss modulus G'', as noted by the arrow in the inset of Figure . At a relatively low crosslinker concentration of 0.2% (S0.2), 𝑡 𝑔 = 30.5 sec, which is too long for efficient SLA printing. Slightly increasing the crosslinker concentration to 0.3% decreases the 𝑡 𝑔 to 23.9 sec (S0.3). As the crosslinker concentration increases from 0.3%. to 2.5%, 𝑡 𝑔 decreases rapidly to 4.0 sec (symbols, Figure ).