Using Tooling Putty for Quick Mold Fabrication

Tooling putty can be one of the most effective ways of
reinforcing or strengthening a mold or tool’s surface. Tooling putty
will add stability and rigidity to any layup mold. The advantages of
tooling putty allow quicker and lighter molds to be built with fewer
needed reinforcement layers. Using it could eliminate hours from a job
that otherwise would be needed to reinforce structural areas of a mold
with fabric materials. If working with complex or fragile molds, adding
tooling putty to a mold’s layup is essential to having a long-lasting,
productive piece of equipment.

Note: Use of the same
resin systems is essential when making a tool, so if an epoxy-based
tooling putty is used, an epoxy-based tooling resin would also need to
be used.

Mold Placement/Prep

Place
the part or the surface on which the tool will be made onto a surface
or flat plate conducive to a mold’s layup. Apply mold release to the
part’s surface from which a tool will be fabricated (per manufacturers
instruction).

Initial Mold Layup

Apply
an epoxy surface coat or tooling gel/resin to the part’s surface as
needed, ensuring coverage of all the given part surfaces. Make a note of
pot life or working time to give enough time to apply needed
reinforcement of plys and putty. Once all part surfaces are covered with
given tooling resin, the application of optional layers of fiberglass
with resin may be added to reinforce the mold. Ensure fiberglass or
reinforcing fabric is adequality wet out, just as a traditional layup.
While the resin is still in a tacky state, mix and apply tooling putty.
Tooling putty may also be used alone to reinforce a mold surface.

Mixing

Most
epoxy-based tooling putty is generally mixed at a 1 to 1 ratio. Measure
out an equal amount of both parts A & B using a scale and cup per
‘Composite Envisions Epoxy Mixing Guide’ and manufacturer’s instruction.
Mixing can be achieved by hand or by stirring. For CE Epoxy 2-part
Tooling putty, more agitation or mixture will pop microbubbles within
the putty matrix yielding a less viscous system. As the putty reaches
desired viscosity, the application can be made by pouring or by hand
onto the tooling surface.

Application to Mold Surfaces

Apply
tooling putty in small amounts to ensure that there is no trapped air
within the tool. Application thickness of the tooling dough should be
between 1/4″ and 1/2″. This thickness will provide adequate support for
multi-use tools and mitigate cracking chances for nearly any mold size
in the future.

Additional Uses:

It is good practice to
place tooling putty into female radii to alleviate any steep draft
angles in the tooling structure. Doing so will also allow for ease of
layup of optional final fiberglass or other fabric layers as the
material will drape over given areas smoothly.

Note: On
molds that are two pieces, do not place Tooling putty onto part edges in
which mating surfaces will be clamped down as this could cause uneven
pressure on the layup surfaces.