Toughen

Regular 
Makes an inanimate object more difficult to penetrate by increasing its DR. Has no effect on the protective value of armor. If the object takes basic damage equal to or greater than its (toughened) DR, the spell is broken, and must be recast.

Duration: 1 hour. 
Cost: 1 to cast per point of DR (maximum of 8) for an object the size of a fist, double for an object up to a cubic foot, triple for an SM 0 object. Same cost to maintain. 
Time to cast: 5 seconds. 
Prerequisite: Shatterproof.

Item 
See Fortify.