Custom Glovebox Feedthroughs Using KF-40 Epoxy Molds

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Custom Glovebox Feedthroughs Using KF-40 Epoxy Molds

Overview

Gloveboxes require custom feedthroughs for many of the cables that connect instruments located inside the glovebox to equipment located outside. These feedthroughs are created by pouring epoxy into a mold surrounding the cable or connector inside a KF-40 adapter fitting.

The current process uses self-mixing Loctite Instant Mix 5-minute epoxy and custom 3D-printed mold pieces designed specifically for the cable or connector being passed through the glovebox wall.

This process was developed by Dr. Torrey McLoughlin at Montana State University with assistance from Josh Gosh at the University of Arkansas.

3D printed epoxy mold pieces used for creating glovebox feedthroughs.

Materials Required

  • KF-40 adapter fitting
  • Loctite Instant Mix 5-minute epoxy
  • Custom 3D-printed mold
  • Sandpaper
  • Clamps
  • CAD software (Fusion)
  • 3D printer (PLA or ABS material)

Procedure

Step 1: Measure the Cable or Connector

Measure the diameter of the cable or connector that will pass through the glovebox wall.

Step 2: Determine Feedthrough Position

For cables, measure how far the cable must extend into the glovebox and mark the location where the feedthrough will be positioned.

Leave a small amount of additional length to provide flexibility during installation.

Step 3: Design the Mold

Design a mold matching:

  • The KF-40 fitting geometry
  • The cable diameter
  • The connector dimensions (if applicable)

Existing CAD files are available in: 

MonArk Quantum Foundry
  → Glove Boxes

Existing designs include:

  • Flange top cover
  • Flange table clamp mount
  • Flange bottom covers for various cable sizes

For connectors, design an additional protective cap to prevent epoxy from entering the connector.

Step 4: Print the Mold

Print the mold using either:

  • PLA
  • ABS

Both materials have been successfully used for this process.

Step 5: Prepare the Cable Surface

Lightly abrade the cable surface using sandpaper in the region that will be embedded in epoxy.

This improves epoxy adhesion and increases mechanical stability.

Step 6: Assemble the Mold

Install the cable or connector into the mold.

Use clamps and the flange table clamp mount to:

  • Hold the assembly together
  • Keep the KF-40 flange level
  • Prevent cable movement during epoxy filling
KF-40 fitting with cable and epoxy mold assembly clamped in place.

Step 7: Fill with Epoxy

Following the manufacturer's instructions, dispense epoxy into the KF-40 fitting.

Approximately:

30 mL of epoxy

is required for each feedthrough assembly.

This corresponds to roughly:

Two syringe volumes

of Loctite Instant Mix epoxy.

Step 8: Cure the Epoxy

The epoxy will:

  • Begin setting after approximately 5–7 minutes
  • Fully harden after approximately 20 minutes

During curing the flange may become noticeably warm due to the exothermic reaction.

A practical indication that curing is complete is when the KF-40 flange has cooled back to room temperature.

Notes and Best Practices

  • Ensure the cable remains centered during curing.
  • Avoid introducing air bubbles while dispensing epoxy.
  • Verify that connectors are protected from epoxy contamination before pouring.
  • Check vacuum compatibility before installation into a glovebox system.
  • Perform a leak test before use in a production environment.

References

  • MonArk Quantum Foundry Internal Procedure
  • Developed by Dr. Torrey McLoughlin (Montana State University)
  • Contributions from Josh Gosh (University of Arkansas)
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