 The addition of rosin to the paste in the second tube facilitates the speed of the reaction and yields a smoother, more homogenous product.Canada balsam and Balsam of Peru are often used to increase flow and improve mixing properties.If the mixed paste is too thin or lacks body before it sets, a filler (such as a wax) or an inert powder (such as kaolin, talc, or diatomaceous earth) may be added to one or both of the original pastes.