Looking for the correct propeller shape to create a small copter
Use Mark Dela's XROTOR - it will give you the chord and twist distribution over span for a given speed, torque and thrust (well, two out of three). 

It is based on Larabee's theory (PFD!) for a minimum induced loss rotor.

For a practical solution try to design an optimum propeller for the speed and torque of your motors and then try to find something similar in a  hobby shop. Building the propeller yourself will be a major effort - just balancing them well will not be easy.

If you are into doing everything yourself, try to carve a master and make a mold, maybe from silicone rubber. Then you can pour as many propellers as you need. Put glass- or carbon fibers into the mold and fill up with thickened epoxy. For thickening use a mixture of cotton short fibers and Aerosil 200. 

The links to the materials are only for background information - I cannot endorse the sources because I have never ordered from those specific suppliers. The method in general will work, though.