Foam dispenser for glass mat substrate

A dispensing head for dispensing foam into a glass mat substrate comprising:

• (a) an elongated chamber having an apertured wall facing said glass mat substrate, said elongated chamber being positioned across the width of said glass mat substrate;
• (b) a conduit opening into said chamber for the introduction of a foam thereinto;
• and
• (c) expandable means positioned within said chamber, said means being expandable to restrict flow of said foam material through said apertures, and said expandable means being moveable within said chamber across the width of said glass mat substrate to control the number of apertures through which the flow of foam is restricted to thereby control the width of foam applied to said glass mat substrate.