One effective method of avoiding having to paint or replace windowsills that have rotted from moisture is to install window trim metal flashing. With the right tools this job can be finished in minutes.
Step 1 – Taking Measurements
The key to good flashing installation for windows is in making accurate measurements. In this case, measure each window frame side width—that is, the wood face and the two board sides.
Step 2 – Mark, Bend, and Cut the Flashing
On the rear surface of your aluminum, both top and bottom, mark the measurements you took in Step 1. Bend your flashing at these marks. Break the flashing at the appropriate place by first scoring it.
Step 3 – Bending the Metal
Place your metal into the bender, top face down. Line up the mark you made on it with the bender edge. Clamp down the bender's top arm. Now bend the metal by lifting the bottom bender arm to an angle of 90 degrees. Finally, return the bottom arm to its original position and remove the metal.