If you are like most people, you've probably had the experience of either locking yourself out of the house or misplacing your house key. Both can be frustrating, especially if you don't have a spare key. Fortunately for you, there are several ways you can make a copy of your house key yourself. While they are only meant as emergency keys, they are great for tucking in your wallet or hiding behind the siding until you can get more info or a spare key made.

1.  Clay Mold

You've probably seen the old soap mold trick in movies when someone, typically the bad guy, steals a key and presses it into a bar of soap to make an impression of the key. If you are like most people, you probably wondered exactly how a copy of the key was made from an impression. While soap isn't the easiest substance to work with, it will work. The easier way to make a key from an impression is with a key casting kit. It is designed with two hinged sides filled with clay so you can mold both sides of the key at the same time. Here's how it's done.

1. Fill the mold with clay and smooth it out, removing any air bubbles. 
2. Dust the clay with baby powder and blow off any excess powder.
3. Press the key into the clay so that about 1/2 of the key bow (the rounded top of the key) rests in the clay.
4. Close the hinged mold and press firmly to make the impression of the key in the clay.
5. Open the kit and remove the key.
6. Close the mold and secure it with the included pins or latch.
7. Melt a alloy slug in a ladle.
8. Pour the metal into the mold and allow it to cool.
9. Open the mold and remove the new key.

2. Soda Bottle Plastic

As crazy as it sounds, you can make a functional spare key from a soda bottle and a piece of tape. Here's how.

1. Cut a 2-inch by 4-inch section of plastic from the bottle.
2. Hold the flat side of the key to a flame to create soot on the key. The side of the key should be black when you are finished.
3. Allow the key to cool.
4. Cover the key with a piece of ordinary cellophane tape and press firmly.
5. Remove the tape. You will now have the outline of the key on the tape.
6. Press the tape onto your piece of clear plastic.
7. Cut out the key with a pair of sharp scissors, following the outline carefully.

3. Photocopy and Tin

For a sturdier copy of your key, you can make a copy using the scanner on your computer, or a photocopy, and tin from a soda can. Here's how to do it.

1. Photocopy of scan the key and make two copies.
2. Cut out the copy of the key, but do not cut out the teeth at this point.
3. Lay the copy on a piece of tin cut from a soda can. Tape it in place.
4. Use tin shears to cut out the shape of the key, leaving room around the teeth.
5. Make the position of the groove to the key, using a ruler to mark the line.
6. Make a similar groove in the tin with the edge of the ruler or other tool.
7. Cut out the second photocopy of the key.
8. Place the photocopy onto the tin key as a guide for cutting the teeth. Making the grove in the key changes to position of the teeth. A second photocopy allows you compensate for the slight shortening of the key due to the groove.

If you aren't up to the challenge of making your own spare key, there are several online key makers that can do it for you from a photo of your key. Simply take a picture of both sides of the key and upload the image to the key maker. Your new key will be shipped to you within a few days.