Standard structural epoxies soften and lose strength well before 150°C, so a bracket or ceramic mount that runs hot needs a different chemistry entirely. Incure Epo-Weld™ UHTE-5320 is a two-part system formulated to hold structural strength at temperatures where ordinary epoxies fail.

What UHTE-5320 is built for

Epo-Weld™ UHTE-5320 is a two-component, ultra-high temperature epoxy for bonding, potting, and repair work in continuous high-heat service. It keeps useful tensile and flexural strength at temperatures that would turn a general-purpose epoxy rubbery, and it resists a wide range of process chemicals and fuels. It bonds well to metals and to technical ceramics such as alumina, which makes it a practical choice for sensor mounts, insulators, and high-temperature fixtures.

The formulation is also compliant with NASA low-outgassing requirements, so it can be used in vacuum systems and space hardware without contaminating nearby optics or sensors.

Key properties and why they matter

• Retained strength at temperature. The number that matters for a hot joint is not room-temperature shear strength but how much of that strength survives at the service temperature. UHTE-5320 is engineered to hold a large fraction of its strength through sustained heat exposure.
• Chemical resistance. The cured matrix stands up to solvents, fuels, and dilute acids and bases, which is essential in chemical-process and engine-adjacent equipment.
• Ceramic compatibility. Alumina and other technical ceramics are common in high-temperature assemblies. UHTE-5320 wets and bonds these surfaces when they are properly cleaned.
• Low outgassing. In vacuum service, volatile content from a curing adhesive can condense on cold surfaces. A low-outgassing grade avoids that problem.

Where UHTE-5320 fits

• Aerospace and defense: bonding structural brackets, heat-shield hardware, and instrument mounts near propulsion and exhaust paths.
• Industrial furnaces and ovens: securing thermocouples, insulators, and fixtures inside heated enclosures.
• Electronics and semiconductor processing: potting and bonding components in deposition and annealing equipment.
• Oil, gas, and chemical processing: repairing and bonding equipment exposed to hot fluids and aggressive chemistry.
• Power generation: bonding sensor housings and support hardware on turbines, boilers, and heat exchangers.

Bonding to ceramics and dissimilar materials

The most common problem in a hot joint is not the adhesive itself but the stress created when two materials expand at different rates. A metal housing bonded to a ceramic insert loads the bond line every time the assembly heats or cools. Keep bond areas modest, control the bond line thickness, and design the joint to load the adhesive in shear rather than cleavage. This guide on how CTE mismatch causes adhesive bond failure covers the mechanism and the design responses in detail.

Not sure whether a bonded joint or a mechanical fastener is the better answer for your part? Email Us with the temperature profile and the substrates.

Surface preparation

• Metals: solvent degrease, abrade to fresh material, then a final solvent wipe and full dry.
• Ceramics: clean thoroughly and lightly abrade; remove all dust before bonding.
• Fired ceramics can hold absorbed moisture, so a short warm-up before bonding improves adhesion.
• Bond promptly after preparation and protect surfaces from handling contamination.

Mixing and cure

Meter the two parts at the specified ratio and mix until fully uniform. UHTE-5320 develops its temperature resistance through an elevated-temperature cure; follow the recommended ramp and hold rather than rushing it, because a short cure leaves the matrix under-crosslinked and it will lose strength early in service. Step the temperature up gradually to avoid trapping volatiles or creating thermal stress in the fixture.

Failure modes and how to prevent them

• Strength loss in service usually means an incomplete cure. Verify the oven profile and extend the hold.
• Cracking on cooldown points to a bond line that is too thick or a joint loaded in cleavage. Redesign for shear and control the gap.
• Poor adhesion to ceramic is generally surface contamination or absorbed moisture. Improve cleaning and add a pre-bond warm-up.
• Voids in a potted section come from trapped air; pour in thin passes or degas the mixed adhesive.

Verifying the cure and the bond

On a critical joint, do not rely on the oven timer alone. Place a thermocouple on a witness part inside the load and log the actual profile; ovens run cooler at the door and in a full load, and a joint that reads 10-15°C low for the hold period can be materially under-cured. After cure, check a sacrificial coupon bonded in the same run: a properly cured UHTE-5320 joint fails in the substrate or leaves a cohesive layer of adhesive on both faces, while a clean interfacial separation points to a surface-preparation or cure problem. Keep a record of the batch, the surface prep, and the measured cure profile for each production lot so a field issue can be traced back.

How UHTE-5320 relates to other high-temperature options

For thin protective films on hot metal rather than a structural bond, a ceramic coating is the better tool; see the range of high emissive ceramic coatings by substrate and service temperature. Within the epoxy line, UHTE-5322 offers a room-temperature cure option and UHTE-5321 is a one-part version that removes the mixing step. If you are also weighing bonded repairs against other methods, this comparison of which adhesive is stronger for heavy-duty repairs is worth a read.

Getting the right grade

The right choice depends on your peak and continuous temperatures, the substrates, and whether your process can support an oven cure. Incure’s technical team can review the application and recommend a grade and cure schedule. Contact Our Team to begin.

Visit www.incurelab.com for more information.