Over the course of the six years that Bedell-Kraus has been selling products direct to the Art Stamp manufacturers, many have questioned the how's and why's regarding Molding Matrix Molds and Rubber Stamps. "Where is the book written on the How to...?" is often questioned. Anderson and Vreeland has a book written regarding Rubber Printing Plates for the Flexographic printing industry. Much of that information is applicable for the Art Stamp manufacturer.
The following information comes from the above mentioned Anderson and Vreeland book, knowledge gained from our father and his 50+ years in the Flexo industry, our experience gained in Custom Molding, knowledge gained from our many customers, and good old trial and error. These situational experiences that often times cause one to ask "it worked yesterday, but doesn't today...why?"
There are certain supplies all Rubber Molders should have:
Micrometeres: It is always good to know the thickness of the matrix, the matrix floor, your original, the ruber to be molded, and that of the final stamp.
Thermometer/Pyrometer: Just to verify the platen temperature is what the molding press says it is. As will be seen, variation of temperature alters the rubber's cure drastically.
Mold Release Spray: usually a silicone type spray.
Release Paper: Again a silicone covered paper used to cover the rubber when molding so it does not stick to the platens. Usually .005" thick.
Matrix Board: The proper matrix board depends on the photoengraving. Type 18 engravings can use Bedell-Kraus' TM2-120. Either Tm2-120 or TM2-125 can be used for Type 11 deep-etched engravings.
Molding Rubber: Usually a natural rubber either brick red, pink, or gray in color. Other colors available. Thickness is usually .090" - .095" but also .075" to .110" is used. For more solids it may be best use thicker ruber, for fine detail type, a thinner gauge is possible.
