I have an old wood stove that had a few cracks that needed repairing as it was sucking in air. I used this to secure them in place with a spatula, wiped off the excess with a sponge (like joint compound) and moments later fired up the oven and slowly let it rise to 500 degrees as directed. I haven't had any re-cracks after about a month, but I've had some chipping/flaking from excess cement that seems harmless so far. The color when dry is a lovely matte black to match our (oven/grill stained) black stove. I'll update when it starts cracking in the areas applied.