Another way to create your own high wattage resistor is to connect multiple resistors in parallel. Let's create a 100ohms resistor with four parallel-connected 400ohms resistors and connect it to a 9V battery. The voltage across each resistor is 9V. So the power dissipation of each resistor is P = V2 / R = 92 / 400 = 0.20W.
Again: always use resistors with the same resistance.