User manual

Z Corporation Z406 System User Manual
70 Z Corporation Service [phone]/(877)88-ZCORP
Choosing a Silicone
There are several aspects to consider for the novice mold maker when choosing a mold material.
The foremost aspect should be whether to use a silicone with a tin or platinum-based catalyst. A
catalyst is a substance that initiates or accelerates a reaction.
Tin catalysts work extremely well for the beginner because they generally have a low durometer, cure
at room temperature, and are virtually inhibition free
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. Low durometer materials make it easy to
create a parting line and remove the master without damaging it. Inhibitors can be powder from
gloves, rubbers, plastics, or chemicals not cleaned from the surface of the master pattern.
Platinum catalysts have a cure cycle that can be accelerated with heat and have virtually no
shrinkage, however they have a higher durometer.
Patterns used to create molds with higher durometers may need draft and must have an excellent
surface finish to de-mold cast parts. It is also recommended that the novice mold maker use a
translucent mold material so the pattern is visible within the mold, making it easier to direct where the
parting line is located.
Manufacturers of Molding Silicone
Hapco (www.hapcoweb.com/
)
Dow Corning (www.dowcorning.com)
General Electric (www.gesilicones.com)
Innovative Polymers (www.innovative-polymers.com)
US Composites (www.shopmaninc.com/moldmaking.html)
Ebalta (www.ebalta.de)
Building the Mold Box
The purpose of a mold box is to contain the silicone rubber (after it is poured over and around a
master pattern) until the silicone turns to a solid. A mold box does not have to be a complex
structure, depending on the size and
configuration of your part; often a can, small
plywood box, pan or plastic bucket will get the
job done. For ease and convenience, plywood,
Plexi-glass, plastic or sheet metal work
extremely well. Be sure not to use a material
that will inhibit the curing of the silicone. Consult
your silicone vendor for a list of these substrates.
The box must have four sides, all of which must
stand higher than the master pattern when
mounted to the gate. The box can be screwed or
nailed together, but clamps are used in most
cases for easy disassembly of the mold box. All
seams of the mold box must be sealed to ensure
the liquid silicone does not leak. Hot melt glue, silicone caulk or clay are effective choices, again be
sure the material chosen will not inhibit the cure of the silicone.
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Inhibition – The failure of silicone to cure within the recommended cure time. Surfaces of the mold will typically remain
gummy, uncured or stick to the master pattern.