Vacuum bag for forming fiber reinforced composite articles and method for using same

A vacuum bag assembly for use with a mold for forming a fiber reinforced composite structure with a fiber lay up by vacuum bag molding, the vacuum bag assembly comprising:

• a sheet having a periphery and an inner surface;
• a resin distribution conduit combined with the sheet so as to be removable from the composite structure with the sheet;
• and
• a plurality of resin distribution passages integrally formed in the inner surface of the sheet, the passages in fluid communication with the conduit for resin flow from the conduit to the passages, the sheet having a stiffness sufficient to prevent collapse of the passages against a fiber lay up under vacuum to permit resin flow through the passages.

A method of forming a fiber reinforced composite structure by vacuum bag molding, the method comprising:

• (a) placing a fiber lay up against a mold surface;
• (b) providing a vacuum bag assembly comprising:
• a sheet having a periphery and an inner surface, the inner surface having a contour which defines spaces between the inner surface and a fiber lay up for distribution of resin when the sheet is placed over the fiber lay up, and
• a resin distribution conduit combined with the sheet so as to be removable from the composite structure with the sheet, said resin distribution conduit in fluid communication with the spaces defined between the contoured inner surface and the fiber lay up;
• (c) sealing the fiber lay up between the mold surface and the vacuum bag assembly, wherein the contoured inner surface of the sheet is disposed adjacent the fiber lay up;
• and
• (d) drawing uncured resin under vacuum through the resin distribution conduit and the resin distribution spaces to impregnate the fiber lay up.