A sales rep from Freemansupply.com has posted a bunch of instructional videos that show various techniques used to build casting molds using various chemicals. Although they suggest to use a specific brand of products, these videos would still be a great visual complement to any mold making instructions.

Do It Yourself Mold Making:

• Making Rigid Molds with Fast-Cast Urethanes [link]
• Urethane Rubber Molds [link]
• Simple Silicon Rubber Molds (no parting line) [link]
• Mold Making – Mass Casting Complex Parts (with parting line) [link]
• Mold Making with Clear Silicon Rubber [link]
• Surface Casting [link]
• Epoxy Laminating Systems [link]