An apparatus and method for improving the tensile strength of a resin impregnated multifilament glass strand are disclosed. The glass strand is conveyed through an impregnating solution, simultaneously being maintained under tension while being vibrated. Each filament vibrates at its respective, natural frequency with the result that the glass strand separates into its component filaments thereby exposing a plurality of interstices to the solution so as to increase the amount of solution absorbed, whereby the tensile strength of the resin impregnated glass strand is improved.