Two pack products have been specifically developed to cure at a certain rate based on the correct chemistry. It is recommended when mixing two component products that the correct mixing ratio is adhered to, as insufficient or additional hardener will result in an incorrectly cured product, which will affect the longevity of the product.

People often run out of hardener and ask if they can use another type of hardener. As a general rule this is not recommended. The exception would be when mixing Epiglass HT9000 Epoxy Resin system: the Fast, Slow and Standard hardeners are fully compatible.