Most instant adhesives soften and lose grip well before 100 degrees Celsius. Incure Heat-Resist 340 is a high-viscosity cyanoacrylate formulated to hold structural loads through thermal shock and sustained heat, in the kind of environment that defeats a standard grade.
What Heat-Resist 340 Is
Heat-Resist 340 is a single-part, high-viscosity cyanoacrylate. It cures at room temperature through contact with trace surface moisture, reaching handling strength quickly and full strength over the following hours. No mixing, no light, and no oven step are required, which makes it well suited to manual assembly and moderate-rate production of metal parts.
The formulation trades some of the raw speed of a thin cyanoacrylate for two things that matter on real hardware: a thick, gap-tolerant body and a cured polymer that keeps its strength at elevated temperature.
Key Properties
- Bond strength up to 5,200 psi on select plastics, with strong performance on common engineering metals when surfaces are clean and lightly abraded.
- High viscosity. The adhesive stays where it is placed, bridges imperfect fit-up, and can be applied to vertical surfaces without running. This suits machined parts where the gap is not zero.
- Thermal resistance. The cured bond resists thermal shock and retains a usable fraction of its room-temperature strength at temperatures that would soften a general-purpose cyanoacrylate.
- Chemical resistance. Withstands occasional contact with alcohols, petrol, aromatic hydrocarbons, and dilute acids and bases after full cure.
- Rapid cure. Reaches fixture strength in seconds to minutes depending on gap, humidity, and substrate.
- Meets Mil-A-46050C, the defense specification for cyanoacrylate adhesives covering viscosity, strength, and cure behavior.
Where It Fits
Heat-Resist 340 is aimed at metal bonding in demanding thermal and mechanical conditions:
- Automotive and aerospace components near heat sources or subject to vibration, such as brackets, clips, sensor mounts, and trim retention
- Industrial equipment and machinery where parts run hot and cannot be welded without distortion
- Oil and gas hardware exposed to heat and hydrocarbon contact
- Defense equipment requiring a qualified adhesive with documented performance
For joints that carry sustained structural load rather than retention or tacking duty, a two-part epoxy is often the better tool. Our comparison of which adhesive is stronger for heavy-duty repairs explains where each chemistry belongs.
Getting a Reliable Bond
Prepare the surface. Degrease with a fast-flashing solvent, then lightly abrade metal to remove oxide and add mechanical key. Wipe again and let the surface dry.
Control the gap. High viscosity tolerates an imperfect fit, but cyanoacrylate cure slows and weakens as the bond line grows past a few tenths of a millimeter. Keep the joint tight and use an activator on wider gaps.
Manage humidity. Cyanoacrylate cure depends on ambient moisture. Very dry conditions slow cure; an accelerator restores speed. Very humid conditions can flash-cure the surface before parts mate.
Allow full cure before loading. Handling strength comes fast, but full thermal and chemical resistance develops over 24 hours. Do not heat-cycle or solvent-expose the joint before then.
If you need to confirm Heat-Resist 340 suits a specific metal pair and temperature profile, Email Us with the substrates and service conditions.
Thermal Cycling and Dissimilar Metals
When Heat-Resist 340 joins two metals with different expansion rates, every heat cycle loads the bond line. The high-viscosity body helps by maintaining a slightly thicker, more compliant bond than a thin cyanoacrylate would, but joint design still matters. Keep bonded areas modest, avoid long unbroken bond lines across a large temperature swing, and let assemblies stabilize thermally before the adhesive fully cures. The underlying mechanism is described in our article on how CTE mismatch causes adhesive bond failure.
When the Heat Exceeds a Cyanoacrylate’s Range
Heat-Resist 340 extends cyanoacrylate service well above a standard grade, but continuous exposure to very high temperature, above the range of any cyanoacrylate, calls for a different material class. For components that must survive sustained radiant heat, a ceramic-based protective coating is the appropriate solution; see our overview of high emissive ceramic coatings by substrate and service temperature.
Storage and Handling
Store Heat-Resist 340 in its original sealed container between 2 and 8 degrees Celsius to protect shelf life. Before use, let a chilled container reach room temperature while still closed, so condensation does not form inside and trigger premature thickening. Keep the cap clean and closed between applications, since cyanoacrylate reacts with atmospheric moisture and a contaminated nozzle will gel.
Uncured adhesive bonds skin quickly. Operators should wear nitrile gloves and work with good ventilation. Cured squeeze-out can be removed mechanically or softened with a dedicated cyanoacrylate debonder; ordinary solvents have little effect once the bond is fully developed.
Summary
Incure Heat-Resist 340 is a high-viscosity, Mil-A-46050C cyanoacrylate for bonding metal parts that run hot, see thermal shock, or face hydrocarbon contact. Prepare surfaces properly, keep the gap tight, manage humidity, and allow a full 24-hour cure before exposing the joint to its service environment.
To specify Heat-Resist 340 for your assembly, Contact Our Team.
Visit www.incurelab.com for more information.