Heat set tissue is a thin tissue that has been coated with a heat activated, acrylic adhesive. The tissue is torn or cut to fit the tear or paper loss, laid in position and covered with silicone release paper (so the tissue doesn’t stick to the hot iron). The tissue is adhered to the paper with a heated iron (approximately 100 degrees F.).
A standard household iron or tacking iron from a hobby store can be used to adhere heat set tissue. It is sold with the silicone release paper.
Heat-set tissue tends to be more brittle than Japanese repair tissue as it does not have the long, strong fibers of the Japanese tissue. It is not recommended for use on the folds in paper or areas that need to flex and bend. Since heat-set tissue is not applied with moisture, it works quite well on shiny, coated paper that can buckle when wet (as might happen with glue or paste).