The resin infusion process has developed as a low-cost method to produce large composite parts in low to medium quantities. Although the process is conceptually simple, the effects of many of the processing parameters on the post-filling stage of the process are not well understood. Most manufacturers tend to develop their approach to infusion process through trial and error, and then adhere to their ‘secret recipe’ without knowledge of the effect of each parameter. This paper describes an experimental investigation of the controllable process parameters and their effect on the final laminate composition, by monitoring local fluid pressure and full field laminate thickness data through the filling and post-filling stages. From the understanding of the effect of each parameter, guidelines are drawn to help manufacturers to optimise their process. The effect of using a ‘brake’ between the part and the vent are evaluated, and the benefits of turning the inlet into a vent at the onset of post-filling are highlighted together with methods of gaining some control on the final laminate fibre volume fraction.