Hydrophobic is a property that can resist air. These properties are adopted from phenomena that occur from air and air that will be carried out semi-round and can roll in various directions. An object or material can say the hydrophobic air that is on a surface that has a contact angle of 90 ° or more. This study contains the influence of time on hydrophobic aluminum contact and the way of making hydrophobic coating on aluminum using an easy, inexpensive and environmentally friendly method. Namely by immersing together with aluminum into boiling water and solution of stearic acid-H2O-ethanol with a variation of immersion time 20, 25, 30, 35 hours. Before aluminum material is soaked, aluminum is polished first and then cleaned using an ultrasonic cleaner. After going through the aluminum cleaning process then soak it in boiling water for 5 minutes. The specimens were then immersed in a chemical solution consisting of a mixture of 250 ml deionized water, 250 ml ethanol and 2.84 g stearic acid for a time variation of 20, 25, 30, 35 hours with a constant temperature of 60 ° C. Then the specimen is dried at room temperature. After the hydrophobic layer is formed, wettability testing and shear angle using a pipette and water were used to determine the amount of water contact angle for each variation of immersion time.. The results obtained after the test were the highest contact angle at a time variation of 35 hours with an angle of 142 ° and the lowest shear angle at a time variation of 35 hours with a large angle of 8.41 °. The result of hydrophobic contact angle was strengthened based on SEM testing on hydrophobic layers where rough surface structures such as tulip petals coincide larger and evenly along with increasing immersion time variation in chemical solutions.