Loctite 438 Black Toughened Instant Adhesive 25ml

Loctite 438 is a black, one-part, rubber-toughened ethyl cyanoacrylate. It is a low-viscosity instant adhesive that cures with atmospheric moisture and needs no mixing.

The rubber toughening adds flexibility, peel strength and shock resistance. It bonds metals, plastics and rubbers, and also porous materials such as wood, paper, leather and fabric.

Where this product is used

• Bonding metals, plastics and rubbers where a flexible, peel-resistant joint is wanted
• Steel and aluminium joints (19 N/mm² and 18 N/mm² lap shear in testing)
• Plastics including ABS, PVC, polycarbonate and phenolic
• Rubbers including neoprene, nitrile and SBR
• Porous materials such as wood, paper, leather and fabric

Features

• Black liquid, one part, no mixing
• Rubber toughened for flexibility, peel strength and shock resistance
• Low viscosity: 100 to 250 mPa·s (cone and plate, 25 °C)
• Cures with atmospheric moisture
• Fixtures in 10 to 20 s on ABS and under 5 s on nitrile rubber (22 °C, 50% RH)
• Lap shear of 19 N/mm² on grit-blasted steel after 24 h at 22 °C
• Bonds metals, plastics, rubbers and porous materials

Key specifications

Choosing the right option

For a clear toughened grade see Loctite 435 Toughened Instant Adhesive 25ml. For another black toughened grade see Loctite 480 Black Toughened Instant Adhesive 20g. Compare the fixture times for your materials.

For a thickened gel that stays put on vertical faces see Loctite 454 Instant Adhesive Gel 20g.

See also: Loctite 480 Black Toughened Instant Adhesive 20g, Loctite 435 Toughened Instant Adhesive 25ml, Loctite 454 Instant Adhesive Gel 20g, Loctite 406 Instant Adhesive for Plastics and Rubbers.

Using it

Fixture times in the data sheet were measured on degreased steel and isopropanol-wiped aluminium. Full chemical and solvent resistance takes at least 24 hours to develop.

The product performs well in thin bond gaps (0.05mm), and larger gaps slow the cure. An activator can speed the cure but may reduce final bond strength; see Loctite 7452 Cyanoacrylate Accelerator 20g.

Do not return used product to the container.

At 22 °C and 50% RH it reaches 0.1 N/mm² in 30 to 45 seconds on degreased steel and 10 to 20 seconds on ABS.

Curing continues for at least 24 hours before full chemical and solvent resistance develops.

Storage and handling

Store unopened and dry at 2 °C to 8 °C. Storage outside this range can adversely affect product properties.

Limits and safety

Not recommended for pure oxygen or oxygen-rich systems, or as a sealant for chlorine or other strong oxidising materials. Lap shear on rubber is low in the Henkel data (0.3 N/mm² on nitrile, 0.4 N/mm² on EPDM), so test the joint on your own rubber before relying on it. Read the safety data sheet before use.