Resin infusion, or vacuum assisted resin transfer molding (VARTM), is a closed mold process that also uses the vacuum bagging technique to compress the laminate. But, in this process dry laminate is placed in the mold and wet out after the vacuum is applied. After the air is evacuated from the vacuum envelope, resin is allowed to flow through ports in the vacuum bag into the laminate stack. This method offers easier handling and fitting of the dry materials in the mold, and the increased compaction produces a laminate with low resin content. It’s this low resin content that gives it the edge over normal vacuum bagging.
Vacuum bagging techniques will normally give you a resin wet out ration of approx. 1:1 ie. for every kg of carbon or cloth used you will use 1 kg of resin. However, with Resin Infusion this ratio drops to 70% ie for every kg of carbon your resin usage is only 700 grams. This represents a weight saving of 15% without compromising the strength.