If anyone has and RFID key that is required to start a car and has tried to get a copy we know it runs over a $100 to get one, and most stores will not just make a non-RFID copy due to legal issues. But if you need one that will just unlock the doors to get the accidentally locked set of keys out, this instructable will show you how to make a real copy of the key from a blank key you can purchase at the store.

Step 1: What You Will Need:

First you will need some common and uncommon materials.

A blank key that has the same V grooves as the real one. For the most part if they will not duplicate it they should sell you the blank, Lowes sold me one for $1.97 (the total cost of this project)
A filing set with different types if files (mainly a round, and a D shaped file)
Non-hardening clay that is not reactive to heat
A grinding wheel or dremel tool to help speed up the process
A vice (optional)
A lead melting pot with Lead or a soldering iron
tape
Some side cutter snips

Step 2: Negative Copy of the Key

First we have to make a negative of the key.

We will do this by molding the clay into a round circle with a rolling pin.
Then we will cut it in half, try to make it as strait of a cut as possible.
Press one side of the key into the clay and make it flush to the clay.
Repeat on the other half of the clay with the opposite side of the key.
Now line up the two half's of the clay, perfection is a must, and lightly apply pressure around the edges of the key imprint in the clay to where it is the same thickness of the original. Now you can press the rest of the clay farther away from the key together to form a better seal so if any molten led does seep out it will not go very far.

Step 3: Lead Casting for a Positive Copy

Now that you have a negative mold of they key we need to come up with a positive temporary copy of it, this is where the lead will come into play. First heat up your lead pot to get some molten lead. I have a lead pot because I do my own bullet casting for my hand guns and shotguns. If anyone wants and instructable on bullet casting just leave a request in the comments section. Now that the lead is molten and around 650ºF put on you safety equipment, I am using welding gloves, safety glasses and a welders apron. when molten lead comes into contact with skin it really, really, really, really, really² hurts. The lead will bubble and spatter when it is poured into the clay mold so be prepared for it. After it has cooled enough to be handled pull it out of our mold and clean off the excess clay. Now we will trim it down to match the origional.

If you are using solder from a soldering iron just get it to drip in the clay mold fast as you can from the tip of the soldering iron. I have never done it this way but it should work in theory

Step 4: Trimming and Grinding

Now that the key is trimmed with side cutters and taped to the blank we need to start grinding the rough shape of the mountains and valleys of the key. For this step you can either use a vice and a Dremel tool or a grinding wheel with a 90º angel on its grinding edge. You will see in the video I used a grinding wheel to get the rough shape. If you do not have a Dremel or grinding wheel you can use the files by themselves it just takes a lot longer.

Step 5: Fine Tuning the Teeth

Now that we have the rough shape of the key ground out we can either keep the lead copy on or remove it and file it by constantly looking back and forth at the original your choice, I did a bit of both. I kept the lead copy on until I got down to where I needed to do the fine details of filing. Now this is the part that will take some time just keep grinding it down and slowly it will begin to resemble the original.

Step 6: Testing the Fruits of Your Labor

After you have it finely tuned and it looks as close to the original as you can get it, test it out. If everything went as it should, you should be able to lock and unlock the car with no problems, now as far as starting it that's another story.

Trying to start a car that requires and RFID chip with a key that does not could damage the computer in the car and not allow it to start correctly anymore, you have been warned.

But if you just need to unlock it then you are fine to use this method.