Hector- I was going to ask what sort of mold making you were interested in - but now you have clarified that.
About 5 or 6 months ago there was a thread here that discussed (or started to) low pressure injection molding. It was a process that used recyclable plastic like soda (Coke) bottles and such.
I think the Gingrich/Gingray/or something like that (spelling - sorry) fellow has a set of plans and one of the Zone members was maybe going to give it a go. Sort of surprised that member hasn't popped in - maybe dropped out. I suspose you have done a search on the CNCZone might look for the other fellow on the web too. He has a whole heap of various plans for simple approaches to similar backyard manufacturing.
Looking forward to hearing your progress!
Cheers - Jim
Here - try this site - might get you close (its GingEry)
http://www.lindsaybks.com/dgjp/djgbk/inject/index.html
Experience is the BEST Teacher. Is that why it usually arrives in a shower of sparks, flash of light, loud bang, a cloud of smoke, AND -- a BILL to pay? You usually get it -- just after you need it.