Loctite 401

Loctite 401

Applicable substrates: metals, plastics and elastomers
Viscosity: Low viscosity
Curing time: 5 seconds
Packaging specifications: 20g/50g/500g
Color: Clear
Viscosity [cP]: 100
Filling Gap: 0.005 in. (0.15 mm)
Cure Time, Steel (Seconds): 5
Shear Strength, GBMS: 2,900 psi (20 N/mm²)
Temperature Range: -40°C to 121°C (-40°F to 250°F)

Overview

Loctite 401 is a medium-viscosity, fast-curing cyanoacrylate (instant adhesive) designed as an all-rounder for bonding a wide variety of materials. It cures in seconds at room temperature when exposed to ambient moisture, forming a strong, rigid bond line.

It’s especially useful when you need to bond mixed substrates, including:

  • Metals (steel, aluminum, copper, etc.)

  • Many plastics and elastomers

  • Porous and absorbent materials such as wood, leather, paper, cork and fabric

Typical characteristics (approximate, for positioning only):

  • Chemistry: Ethyl cyanoacrylate

  • Appearance: Clear, colorless liquid

  • Viscosity: Medium (flows enough to wet surfaces, but not too runny)

  • Fixture time: Usually a few seconds to under 30 seconds, depending on materials and gap

  • Service temperature (typical): around –40 °C to +80 °C

This balance of speed, strength and versatility is why Loctite 401 is often chosen as a “general-purpose” CA in both production and maintenance.

Key Features & Benefits

  • Universal substrate compatibility
    Bonds metals, most plastics, elastomers and porous substrates, making it ideal when you don’t want multiple different instant adhesives in stock.

  • Fast fixture at room temperature
    Achieves handling strength in seconds on many materials, keeping assembly and repair work moving quickly.

  • Medium viscosity for controlled flow
    Thin enough to wick into tight joints, but viscous enough to stay where you apply it and not run everywhere.

  • Good performance on porous materials
    Compared with very low-viscosity CAs, Loctite 401 is less likely to soak straight into substrates like wood, paper or leather, giving better actual bond-line build.

  • Single-component, easy to use
    No mixing, no heat; just apply to one surface and assemble. Great for line-side assembly, repair benches and field work.

  • Small amounts go a long way
    CAs work best in thin bond lines, so only a small drop is needed, which helps control cost per joint.

Typical Applications

Loctite 401 is widely used in:

  • General industrial assembly

    • Bonding plastic or rubber components to metal housings

    • Fixing small parts, clips, guides and pads

    • Quick fixture before mechanical fastening

  • Electronics & electrical devices

    • Securing strain reliefs, grommets and cable boots

    • Bonding small plastic parts around switches, LEDs and connectors (where compatible)

  • Furniture, craft and hobby work

    • Bonding wood, MDF, leather, cork and fabric in small fixtures and decorative elements

    • Quick repairs on fixtures and displays

  • Maintenance & repair (MRO)

    • Rapid repair of broken plastic covers and knobs

    • Re-bonding rubber feet, gaskets and seals where flexibility is not critical

For low-surface-energy plastics (PP, PE, PTFE), you’ll typically pair Loctite 401 with a suitable polyolefin primer to improve adhesion.

How to Use Loctite 401

Always follow the latest Technical Data Sheet (TDS) and your plant procedures. This is a practical summary.

Step 1 – Surface preparation

  1. Ensure both surfaces are clean, dry and free from oil, dust and release agents.

  2. Degrease metals and glossy plastics with a suitable solvent.

  3. Light abrasion (followed by cleaning) can improve adhesion on many metals and rigid plastics.

Step 2 – Application

  1. Apply a small drop or thin bead of Loctite 401 to one of the bonding surfaces.

  2. Aim for a thin, even film—excessive adhesive will slow cure and can reduce final strength.

  3. For porous materials, you may need slightly more adhesive, but still avoid flooding the joint.

Step 3 – Assembly

  1. Bring the parts together quickly and align them correctly; cure starts as soon as surfaces contact.

  2. Press together firmly to squeeze the adhesive into a very thin bond line.

  3. Hold parts in place until handling strength is reached (usually seconds to tens of seconds, depending on substrate, gap and humidity).

Step 4 – Cure & handling

  1. Avoid disturbing the joint until it has fully set.

  2. For maximum properties, allow up to 24 hours at room temperature after assembly before applying full load, especially on critical parts or larger bond areas.

Step 5 – Cleanup

  • Wipe away uncured squeeze-out immediately with a compatible solvent.

  • Once cured, cyanoacrylate is best removed by mechanical means (scraping, careful cutting) or a dedicated CA debonder.

Safety & Handling

  • Bonds skin and eyes in seconds – avoid contact with skin; never touch eyes if adhesive is present.

  • Use in a well-ventilated area; vapors can irritate eyes and respiratory tract.

  • Wear safety glasses and suitable gloves (e.g., nitrile) when handling repeatedly or in production.

  • Keep away from cotton or wool; rapid polymerization can generate heat and cause material to harden or smoke.

  • Store in a cool, dry place, tightly closed, ideally in the original container.

  • Dispose of adhesive and contaminated materials according to local regulations; don’t pour liquid CA into drains.

Always consult the current Safety Data Sheet (SDS) before frequent or large-scale use.

FAQs

Q1: What is Loctite 401 mainly used for?
Loctite 401 is mainly used as a general-purpose instant adhesive for fast bonding of metals, plastics, elastomers and porous materials in assembly, repair and hobby applications.

Q2: How is it different from other Loctite instant adhesives?
Loctite 401 is positioned as a universal, medium-viscosity CA with good performance on porous and mixed substrates. Other grades may be optimized for low odor, high temperature, rubber-toughening, low viscosity wicking, etc.

Q3: Can Loctite 401 bond porous materials like wood and leather?
Yes. One of its strengths is handling porous materials such as wood, leather, paper and fabric better than very thin CAs, which tend to soak in too quickly.

Q4: How fast does Loctite 401 cure?
It typically fixtures in seconds—often under 30 seconds—depending on material, gap and humidity. Full cure and maximum properties are usually reached within 24 hours at room temperature.

Q5: Does Loctite 401 need any mixing or heat?
No. It is a single-component, room-temperature curing adhesive activated by surface moisture. No mixing or external heat is required for normal use.

Q6: Can I use Loctite 401 on polyethylene or polypropylene?
On its own, adhesion to PE, PP and PTFE is poor. To bond these, you typically need a special primer for polyolefins, or a different adhesive system designed for those plastics.

Q7: Is the cured bond flexible?
Cured Loctite 401 forms a rigid bond line. It can tolerate some movement in small, stiff parts, but it is not a flexible adhesive. For joints that flex or peel significantly, a rubber-toughened CA or structural adhesive may be better.

Q8: How can I remove Loctite 401 if I make a mistake?
Uncured adhesive can often be wiped away with a suitable solvent. Once cured, removal usually requires mechanical methods (scraping, cutting, sanding) or a commercial cyanoacrylate debonder, and may damage the substrate.

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