LOCTITE 5188 Highly Flexible Anaerobic Flange Sealant for Gearboxes and Engine Casings

LOCTITE 5188 Flange Sealant Benefits

LOCTITE 5188 Flange Sealant combines high flexibility with strong chemical and oil resistance. Unlike cut gaskets that may compress, relax, or require inventory in multiple shapes, the liquid material follows the flange geometry and fills machining marks and small surface irregularities. Once cured, it helps prevent fluid leakage while remaining flexible after exposure to elevated temperatures and normal flange movement.

The one-part formula requires no weighing or mixing, reducing preparation time and ratio errors. Its high viscosity allows controlled bead dispensing without excessive running, and positive ultraviolet fluorescence supports application inspection. The product can be applied manually, by roller coating or screen printing, or through compatible robotic dispensing equipment for repeatable high-volume production.

Applications for LOCTITE 5188 Flange Sealant

This anaerobic flange sealant is designed for rigid metal connections such as engine casings, gearbox covers, transmission housings, pump flanges, compressor assemblies, axle housings, bearing covers, and industrial machinery. It is particularly useful on aluminum flanges where excellent adhesion and flexibility are required. It can also be used on correctly prepared steel flange surfaces.

The product provides resistance to low pressures immediately after assembly, helping manufacturers perform controlled leak testing before full cure. Henkel recommends testing uncured assemblies only at low pressure. The material is intended for close-fitting machined flanges rather than large, flexible joints or wide structural gaps.

LOCTITE 5188 Flange Sealant Technical Performance

The uncured material is a red, viscous dimethacrylate ester with a typical specific gravity of approximately 1.1 at 25°C. Published cone-and-plate viscosity ranges from 11,000 to 32,000 mPa·s. Henkel lists a fixture time of approximately 25 minutes on steel, unprimed gap filling up to 0.25 mm, and an operating-temperature range from -55°C to 150°C.

After curing, the product maintains high flexibility, with published elongation at break near 186%. Typical lap-shear performance develops on both grit-blasted mild steel and aluminum. Chemical-resistance testing demonstrates durable performance after exposure to motor oil, automatic-transmission fluid, water-glycol mixtures, fuel, and diesel exhaust fluid under specified conditions. These values are typical reference data and should be verified in the actual assembly.

How to Apply LOCTITE 5188 Flange Sealant

Clean the mating surfaces and remove old gasket material, loose contamination, heavy grease, and excess oil. Dispense a continuous bead around the flange face and bolt holes where required. Assemble the components promptly and tighten fasteners as soon as possible using the equipment manufacturer’s recommended sequence and torque to avoid unwanted flange separation.

Allow the sealant to cure before exposing the assembly to full pressure, high loads, or aggressive service fluids. Cure speed depends on the metal, temperature, flange gap, and surface condition. Production engineers should validate bead size, application pattern, fixture time, pressure test, and final durability under the expected operating conditions.

Why Buy LOCTITE 5188 Flange Sealant?

LOCTITE 5188 Flange Sealant offers highly flexible sealing, excellent oil and chemical resistance, instant low-pressure sealing, reliable aluminum adhesion, and convenient one-component processing. It is a professional choice for manufacturers and maintenance teams seeking a durable alternative to pre-cut gaskets on rigid metal flanges.

Review the official Henkel LOCTITE 5188 Technical Data Sheet before qualification, storage, or production use. Explore our industrial flange sealants for additional anaerobic gasketing solutions for engines, gearboxes, pumps, transmissions, and machinery.