Mod Rock is extremely fast. Its like a bandage of gauze with plaster of paris mix that you just soak briefly in warm water then apply as if you would the same cast technique they use in hospitals for broken limbs.

Having used this product myself in the past I would suggest you might like to cut the powdery gauze bandage into smaller strips making it easier to handle, then soak it before applying. It generally starts to get quite warm and sets quite fast.

It can be used over just about anything and can be painted if required. The whole process could take less than a few hours.