LOCTITE 222

Loctite 222

Loctite 222 is a low-strength threadlocker ideal for weak metals such as aluminum and brass that tend to break during disassembly. Common applications include adjusting countersunk screws, set screws, and other screws in collars, pulleys, toolholders, and controllers.

Strength: General purpose, low strength, dismantled with hand tools
Temperature range: 150°C
Maximum bolt size: M8
Packaging: 50 ml/250 ml
Color: Purple
Viscosity (cP) at 20 rpm: 1200
Thixotropy: Yes
Breakaway torque/average dismantling torque, M10 steel nuts and bolts (N.m, lb.in): 6/14 N.m; 50/120 lb.in
Temperature range: -55°C to 150°C (-65°F to 300°F)
Fixture time (min): 20

Overview

Loctite 222 is a purple, low-strength, low-to-medium viscosity anaerobic threadlocker formulated for small diameter fasteners and assemblies that are sensitive to high breakaway torque. It cures in the absence of air, between close-fitting metal surfaces, forming a plastic-like solid that gently locks threads without making disassembly difficult.

Once cured, Loctite 222:

  • Reduces loosening from vibration and thermal cycling

  • Helps seal the thread helix against moisture and light leakage

  • Provides basic protection against rust and fretting corrosion

It’s the classic choice when you want “just enough” locking to keep screws in place, but you still need to adjust, calibrate or service the assembly regularly.

Why choose Loctite 222?

1) Designed for small screws and weak substrates
Loctite 222 is widely used on small diameter screws, light alloy housings and components where stronger threadlockers could strip threads or make removal difficult. It’s well suited to instrument screws, control panel screws and fasteners in soft metals.

2) Easy disassembly with normal hand tools
Because it’s a low-strength grade, fasteners locked with 222 are typically undone with standard screwdrivers or hex keys, without the need for heat or impact tools. This makes it ideal for precision devices, electronics housings and light mechanical assemblies.

3) A cleaner alternative to mechanical locking devices
Instead of spring washers or thread-taped screws, Loctite 222 provides full-thread engagement and chemical locking, which often improves consistency and reduces loosening while simplifying the bill of materials.

4) Locks and lightly seals in one step
By filling small clearances in the thread, Loctite 222 helps seal out moisture and light vapours, supporting long-term reliability in small assemblies without adding separate seals.

5) Easy to see, easy to inspect
The purple colour distinguishes it from medium-strength blues and high-strength reds. Under UV light, the adhesive is typically fluorescent, helping quality inspectors verify that threadlocker was actually applied.

Typical Applications

Delicate screw joints

  • Small machine screws on electronics enclosures and PCBs

  • Instrumentation, meters and control panels that need periodic recalibration

  • Screws in light alloy housings where stronger grades might damage threads

Adjustment and calibration screws

  • Set screws on potentiometers, trimmers and stops

  • Locking of adjustment screws on valves and actuators that are tuned in the field

  • Optical and measuring equipment where precise positioning must be maintained but still adjustable

Light-duty mechanical assemblies

  • Covers, guards and brackets that see vibration but must be easy to remove

  • Fasteners where traditional lock washers or nylon inserts are not convenient

Loctite 222 is intended for metal-to-metal threads and should not be used on plastics that are sensitive to stress cracking.

How to Use Loctite 222

Step 1 – Prepare the threads

  • Remove dust, loose corrosion and old threadlocker from the fastener and tapped hole.

  • Wipe off heavy grease and thick oil; light oil films are usually acceptable, but cleaner metal provides more predictable results.

Step 2 – Apply the product

  • Shake the bottle briefly.

  • Apply a small, continuous bead of Loctite 222 to the male threads, covering the area that will be engaged.

  • For very small screws, one or two small drops is typically sufficient; avoid flooding the area.

Step 3 – Assemble and tighten

  • Install the fastener and tighten to the torque specified for your design.

  • Avoid repeatedly tightening and loosening once the product has started to cure, as this can disturb the bond line.

Step 4 – Allow to cure

  • Loctite 222 develops handling strength in a relatively short time under normal conditions.

  • For full performance, allow curing at room temperature (typically up to 24 hours) before exposing the joint to full vibration, load or temperature extremes.

Step 5 – Disassembly

  • Loosening is normally achieved with standard hand tools (screwdriver, Allen key, small wrench).

  • For most assemblies, no heat is required, which is exactly why 222 is preferred for serviceable small fasteners.

Safety & Handling

Typical safety information for low-strength anaerobic threadlockers like Loctite 222 includes:

  • May cause eye and skin irritation on contact.

  • Repeated or prolonged contact may cause skin sensitisation in susceptible individuals.

  • Vapours in poorly ventilated spaces can cause mild respiratory irritation.

Basic precautions:

  • Use in a well-ventilated area.

  • Avoid contact with skin and eyes; wear safety glasses and suitable protective gloves.

  • Wash hands thoroughly after handling and before eating or drinking.

  • Do not allow uncured product to enter drains or watercourses.

  • Store in the original, tightly closed container in a cool, dry place away from heat and direct sunlight.

Always read and follow the latest Safety Data Sheet (SDS) for Loctite 222 in your country or region.

FAQs

Q1: When should I choose Loctite 222 instead of 242 or 243?
Choose Loctite 222 when you are working with small screws, delicate components or soft metals and need very easy disassembly. Use medium-strength grades like 242/243 when you want stronger locking and less frequent adjustment.

Q2: What fastener sizes are best suited for Loctite 222?
Loctite 222 is typically used on small-diameter fasteners—for example, screws in instrument panels, covers and light mechanical assemblies. On large bolts, the low strength may not be sufficient to resist heavy loads or shock.

Q3: Can I use Loctite 222 on stainless steel or plated screws?
Yes. Loctite 222 is suitable for many common metals, including stainless and plated fasteners. Cure may be slower on passive metals, so allow extra cure time before putting assemblies under full stress.

Q4: Is Loctite 222 oil-tolerant?
It can tolerate light oil residues, but performance will drop if threads are heavily coated with oil, grease or anti-seize. For best results, remove heavy contamination and apply 222 to reasonably clean metal surfaces.

Q5: Can I use Loctite 222 on plastic threads?
No. Anaerobic threadlockers like 222 are designed for metal-to-metal joints and can cause stress cracking in some plastics. For plastic fasteners or mixed metal/plastic joints, use an adhesive specifically formulated for plastics.

Q6: Does Loctite 222 help with sealing, or is it only for locking?
Loctite 222 primarily locks the fastener, but because it fills small gaps in the thread engagement, it also provides a light sealing effect against moisture and low-pressure fluids, which helps prevent corrosion and minor weeping.

Q7: How often can I remove and reapply Loctite 222?
You can remove and reapply 222 as often as your maintenance schedule requires. Each time you disassemble, clean off old cured residue from the threads, then reapply fresh product to maintain consistent performance.

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