The TCS Fusing Liquid is used for repairs and additions to existing TCS Unbreakable Partials. The Fusing Liquid is ONLY used when flasking and injection are necessary. Immediately prior to injection a drop of the TCS Fusing Liquid is applied to the area that requires bonding . The TCS Fusing Liquid begins to deteriorate the exitsting TCS Unbreakable and when new TCS Unbreakable is injected to that area, a bond is created that is virtually undetectable. This product is not for use with the Hot Air Welder, it is ONLY for re-injection.