This DVD is sold by Polytek Development Corp. which also sells the products shown and used. Note that the methods and techniques shown can easily be used with other brands of rubber. Running time is just short of 45 minutes.

This DVD is very low-cost : $5.95 (add S&H). It was bought as I was interested in making my own molds at the time. That made it an ideal candidate to review. Note that this DVD is full with lots of details which won't be mentioned here. The review should give you enough info to see if you'd benefit from buying the DVD for your own use.

Introduction

The president of the company starts by saying a few words and tells us what the DVD holds. In short, it shows three different ways to make molds using Polyurethane and Silicone rubber products.

You see a real person make three different mold types. Every details of every step is shown which makes it a complete tutorial on the subject.

Poured block mold using Polyurethane liquid rubber

This is probably the easiest way to make a mold, but it is also the most expensive.

Basically, a mold box is created and the master is placed in it. After sealing the model, the rubber is measured, mixed and poured into the mold box.

The Polytek DVD shows every step in great detail and includes tons of great tips and hints. An example for poured block molds : pour the rubber at the lowest point of the mold box to avoid trapping air.

The entire method is clearly shown, including the demolding process.

Brushed blanket mold using polyurethane liquid rubber and liquid plastic shell

As this chapter's title suggests, a blanked mold is brushed onto the master. Once cured, this flexible mold is backed up with hard, plastic shell. This gives you the benefits of a strong, rigid mold shell combined with a flexible mold.

Here again, the entire process is clearly illustrated, starting with the measuring and mixing of materials used to make the mold.

Great tips and hints : Start brushing at the lowest part of the master, again to avoid trapping air. Avoid trapping air between the brushed-on layers of blanket mold. During the cure, these layers will heat up, causing the air bubble to expand. This could deform the mold.

The hard plastic shell is made in two parts. Key channels are used to ensure the two parts will go together correctly in future. Information like this is what makes this DVD well worth the (cheap) purchase price.

Poured blanked mold using Silicone rubber and a liquid plastic shell

This is a similar method to the last one, with an added benefit. With this setup, the blanket mold and easily be replaced, if needed. Simply poor a new one.

First, the model is covered with clay. After applying wax and release coats, the hard shell is created on top of the clay.

Excellent tip : Cover the master with plastic wrap before applying the clay. This prevents clay from getting where you don't want it.

Once the shell cures, a hole is drilled in it to pour in the rubber. Holes are also drilled where the high points in the mold will be. This is again done to prevent trapped air bubbles.

After sealing the master, the shell is placed over the master and silicone rubber is poured between the two.

This method allows for the benefits of silicone molds (no release needed) without the high price tag of using all silicone rubber.