Infusion is an efficient production-friendly layup process for complex shapes. It provides more consistent weight per part than wet layup and requires less worker training compared with open molding or pre-preg work, making infusion a popular choice among complex design manufacturers. Used on skins, cores and structures - including stringers - in one shot it is even possible to make very large parts in one go with infusion requiring some finicky bagging but once you master its controls it becomes easy and repeatable.At the core of infusion lies vacuum. A reliable pump that is capable of drawing air from beneath your bag should be at hand to create this. I recommend having two vacuum pumps - one high vacuum and one low - because during the initial part of your infusion (the "high vacuum" stage), you want as much differential between atmospheric pressure and your pump as possible - such as using a rotary vane or oil-lubricated industrial pump for this part.One key element of successful infusion is having an effective flow-media for your resin. Automotive & Marine composite repairs One solution for achieving this is by using "non-crimp" fabrics - stitched or woven unidirectionals with natural channels to let the resin pass through more freely - while some manufacturers offer infusion specific fabrics with additional stitching or wider spaced fiber bundles that facilitate greater resin flow.