This is a simple how-to on making a rusty padlock prop.

Materials required:

Scrap piece of Styrofoam
Pencil or marker
Furniture/upholstery nails (dome headed) or similar
Short length of flexible tubing or similar
Fine grain sandpaper
Acrylic paints in Black and brown tones

First of all, you can do an internet search for images of an old padlock to get an idea of the shape of padlock you want

For this how-to I have used a classic shape padlock, 18th century style

Step 1. Draw the shape of the padlock onto the piece of Styrofoam

Step 2. Cut the Styrofoam to shape

Step 3. lightly sand the Styrofoam, especially on the edges

Step 4. Cut out the keyhole shape using a craft knife

Step 5. Pin the upholstery nails in place on the Styrofoam

Step 6. Using a pen or pencil, make two holes in the top of the Styrofoam

Step 7. Insert the two ends of the tube into the holes.

Step 8. Paint everything Black

Step 9. Sponge paint the lock with the Brown paints to give a rusty appearance

Here is another example of a different style lock made the same way

You can make the locks as big or small, and to any design you need using this technique, and use whatever finish you require