If you think it is impossible for you to create your own plastic prototypes you're mistaken. All you have to do is follow the steps in this video. You'll even be told where to get the materials you need. Of course they will cost money but not a fortune and certainly not even a hundredth of what it would cost you to get a professional engineering job done and a mold cut. Probably less than a tenth what a computer generated plastic model would cost too. True, you won't be able to crank out 5,000 parts in an afternoon but you certainly should be able to produce 10 or 20 units that you can use for testing or having others test or even for sales testing.

The video starts with a quick overview and some definitions then actually shows you hands on how to do things. You get to see the plug take shape then the mold-box then the mold then the part. And once that first part is produced it's a simple matter to make 10 more. You get to see exactly how Randy has solved some of the common problems that plague hand-made hand-cast-plastic parts, and you get to see his creative ways of simplifying issues such as release and bubble evacuation without expensive equipment.

Many of the materials and nearly all of the equipment will be stuff that you may already have at home though you will probably want to specifically get some materials from your local hardware, lumber, hobby, office supply, or even grocery store just so you have a supply in hand that you'll only use for making your own plastic parts. The only tricky parts are the castable mold material and the plastics themselves. These will be 2 part materials that you measure and mix yourself (from the suggested suppliers) just before you put them to use---all at room temperature. No tricky heating, no fancy injection equipment (well, OK, the $6 syringe from Home Depot), no major danger to fingers or toes.

But there are risks, there always are, though in this case not very big. Even then Randy tells you how to minimize the risks with practical, easy to do suggestions. In fact once you see just how simple it is you may get so carried away making plastic parts that you don't get any real work done toward your goal of being a successful independent inventor.