DIY- How to Make a Plastic Spare Key




I was locked myself out of my house or car many times, but keeping extra keys in pocket or wallet is really not a comfortable experience, so I try to make a flexible and thin plastic spare key myself by cutting a plastic strip from soda bottle or old credit card, the plastic key can push the pin up, but plastic key is not strong enough to turn the lock, the tension wrench is needed, so I have an idea to combine a plastic strip and  tension wrench, and turn it into final product, you can find it on

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Step 1: Sep1. Print the Copy and Cut It Out

Scan and print a copy in 1:1 ratio of the original key, highlight the outline with the  pen and the ruler to ensure it looks clearly, cut out the bottom edge and shoulder accurately and cut the tooth side roughly, just leave excess paper around the tooth.


Step 2: Step2. Stick the Printout Onto the Blank

Line up the key blank with cut printout, make sure to align the bottom edge and shoulder exactly, and stick it onto the blank with the glue stick.

Step 3: Step3. Cut the Tooth and Tip

This is the crucial part, it must be very accurate, press the hobby knife down around the highlighted outline to cut into the plastic blank, this allows you to get quite accurate cuts without maneuvering around the knife risking over cutting.


Step 4: Step4. Use the Key

Insert the key into the lock slowly and wiggle it gently, before you turn the key, make sure the metal tension wrench is inserted into the keyway completely, it does the turning, otherwise the plastic part may be damaged. If you find your copy isn’t quite working, compare it to the original key, fix and clean it use a small file.




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      4 Discussions


      9 years ago on Introduction

      Spam.  Sorry. Does look like a good product, though.  Maybe if you walked us through how you built the prototype.

      1 reply

      9 years ago on Introduction

      This would be some kind of "infomercial"? If want spare keys, I have them copied in metal.



      9 years ago on Introduction

      I saw this once with where someone did the picture and used a soda can to open the door.  One time use to be sure, but it would provide enough strength to turn the lock.  Perhaps if you put a strip around the lower half of the key it would be able to turn the lock that way.