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Using Tooling Putty for Quick Mold Fabrication

Mar 31st 2021

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.