A model for pseudoboehmite crystallite packing formed during the hydrolysis of trisecbutoxyaluminium is postulated. The model describes platelike crystallites of pseudoboehmite stacked in a sharing edges only configuration. With this type of stacking, the pore sizes detected are approximately equal to the crystallite sizes of the hydrolysates. The hydrolysates age via a dissolution reprecipitation reaction. This increases the size of the crystallite size of the pseudoboehmite formed, speeding peptization by allowing nitrate ions to enter pores and access the surfaces of the crystallites. This type of model also allows an explanation for the peptization kinetics of systems containing sec-butanol formed during the hydrolysis of trisecbutoxyaluminium.