Henkel LOCTITE 403 Low-Odor Instant Adhesive for Plastic, Rubber and Metal Bonding

LOCTITE 403 Low-Odor Instant Adhesive Performance

LOCTITE 403 is based on alkoxyethyl cyanoacrylate technology. It cures when confined between close-fitting surfaces in the presence of atmospheric moisture. The one-part formulation simplifies manual application and automated dispensing because operators do not need to measure components, control a mixing ratio, or manage a limited two-part working life.

Henkel’s current product information lists a representative viscosity of approximately 1,200 mPa·s. The official technical data sheet provides a cone-and-plate viscosity range of approximately 900 to 1,500 mPa·s at 25°C and a typical specific gravity of 1.1. This medium-viscosity consistency provides more placement control than a very thin instant adhesive while still flowing effectively across close-fitting surfaces and small gaps.

The maximum published gap-filling capability is approximately 0.20 mm. Thin bond lines normally cure more quickly and provide more consistent performance, while larger gaps reduce cure speed. The product is therefore most effective on parts with accurate dimensions, good surface contact, and controlled adhesive volume.

LOCTITE 403 Low-Odor Instant Adhesive Applications

LOCTITE 403 Low-Odor Instant Adhesive can bond compatible steel, aluminum, ABS, PVC, polycarbonate, phenolic materials, nitrile rubber, neoprene, wood, leather, paper, and fabric. Its ability to cure on porous or absorbent materials makes it useful for applications where conventional instant adhesives may be absorbed too quickly or may not develop reliable fixture strength.

Typical applications include attaching rubber seals to metal housings, assembling plastic covers, fixing appliance components, bonding electronic enclosures, joining decorative parts, installing nameplates, repairing leather items, assembling wood products, and bonding fabric or paper components. The low-bloom characteristic is particularly valuable on black plastics, transparent parts, polished surfaces, decorative assemblies, and other products where white cyanoacrylate residue could affect appearance.

Difficult low-surface-energy materials such as polypropylene, polyethylene, and PTFE may require a suitable primer such as LOCTITE SF 770. Because plastic grades, additives, mold-release agents, coatings, and surface treatments vary, adhesion, appearance, environmental resistance, and stress-cracking behavior should be tested on representative production parts.

7 Benefits of LOCTITE 403 Low-Odor Instant Adhesive

• Low odor: Supports production areas where controlling cyanoacrylate vapor is difficult.
• Low blooming: Helps reduce visible white residue around decorative and cosmetic joints.
• Ultra-clear appearance: Produces a clean bond line on visible consumer and industrial assemblies.
• Medium viscosity: Provides controlled dispensing and fills gaps up to approximately 0.20 mm.
• Rapid fixturing: Develops handling strength within seconds on many compatible materials.
• Broad substrate range: Bonds plastics, elastomers, metals, wood, leather, paper, and fabric.
• One-component processing: Eliminates measuring, mixing, curing ovens, and separate hardeners.

LOCTITE 403 Low-Odor Instant Adhesive Fixture Times

Fixture time varies according to substrate, bond gap, temperature, humidity, and surface condition. At approximately 22°C and 50% relative humidity, Henkel reports fixture times of 20 to 45 seconds on steel, 5 to 20 seconds on aluminum, 5 to 10 seconds on nitrile rubber, 20 to 40 seconds on neoprene, 5 to 10 seconds on ABS, 45 to 75 seconds on PVC, and 10 to 20 seconds on polycarbonate.

Reference fixture times for porous materials include approximately 10 to 20 seconds on leather, 20 to 30 seconds on pine wood, and less than five seconds on paper. The recommended workplace relative humidity is approximately 40% to 60% at 22°C. Lower humidity generally slows curing, while very high humidity may accelerate fixture but can reduce final strength.

Strength and Operating Temperature

After 72 hours at 22°C, Henkel reports typical lap-shear strength of approximately 20.3 N/mm² on grit-blasted steel and 14.1 N/mm² on etched aluminum. Published reference strengths also include approximately 8.6 N/mm² on ABS, 6 N/mm² on polycarbonate, and 16.1 N/mm² in a polycarbonate block-shear test.

The current official product page lists an operating-temperature range of approximately -40°C to 80°C. Laboratory testing also shows useful resistance to motor oil, gasoline, ethanol, isopropanol, water-glycol mixtures, humidity, and water after full curing. Finished-product performance depends on the joint design, substrate, adhesive thickness, loading direction, temperature duration, and chemical exposure.

Applying LOCTITE 403 Low-Odor Instant Adhesive

Clean the bonding areas and remove oil, grease, dust, moisture, oxidation, release agents, and loose contamination. Apply a small controlled quantity to one surface. Do not use tissue, cotton, or a brush to spread cyanoacrylate adhesive because rapid reaction with absorbent materials may generate heat.

Join the parts within a few seconds and position them accurately before fixture occurs. Maintain firm contact until sufficient handling strength develops. Excess adhesive can slow curing, increase blooming, and reduce joint consistency, so apply only enough material to wet the required bonding area.

An approved activator can accelerate curing on large gaps or inactive surfaces, but it may reduce ultimate bond strength. When both primer and activator are required, follow Henkel’s recommended sequence and avoid applying the adhesive directly to the activator-coated surface. Production trials should verify the complete process.

Although useful handling strength develops quickly, curing continues for at least 24 hours before full chemical and solvent resistance is achieved. Depending on the materials, gap, temperature, and humidity, allow approximately 24 to 72 hours before exposing the joint to maximum service loads.

Storage, Safety, and Official Product Resources

Store unopened containers in a dry location between 2°C and 8°C. Keep the bottle tightly closed and protect the adhesive from moisture and contamination. Allow refrigerated material to approach the required dispensing temperature while the container remains sealed to reduce condensation. Never return dispensed or potentially contaminated adhesive to the original bottle.

LOCTITE 403 should not be used in pure oxygen or oxygen-rich systems and is not recommended as a sealant for chlorine or other strong oxidizing materials. Review the current safety data sheet before industrial handling.

Review the official Henkel LOCTITE 403 product page and the official LOCTITE 403 technical data sheet for current specifications, processing guidance, safety documentation, and regional package availability.

Explore our low-bloom instant adhesives for additional clean-appearance bonding materials. Browse our industrial cyanoacrylate adhesives for rapid assembly of plastics, rubber, metals, wood, leather, paper, and fabric.