Principle 31. Porous materials

1. Make an object porous or add porous elements (inserts, coatings, etc.).
   Drill holes in a structure to reduce the weight.
2. If an object is already porous, use the pores to introduce a useful substance or function.
   Use a porous metal mesh to wick excess solder away from a joint.
   Store hydrogen in the pores of a palladium sponge. (Fuel "tank" for the hydrogen car--much safer than storing hydrogen gas)