Loctite Threadlocker - 221 - Low Strength - Low Viscosity - 50ml
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Product Information
Full details
This guide is for DIY enthusiasts and professionals working with small threaded fasteners where easy disassembly is a priority. The Loctite 221 offers reliable locking and sealing against vibration and shock while allowing for removal with standard hand tools. A key caveat is its reliance on metal-to-metal contact for curing, meaning it won't perform optimally in the presence of air gaps or non-metallic components.
All features
| Model Part Number | 135331 |
|---|---|
| Brand | Loctite |
Extended Product Information
FAQs
What is the primary use for Loctite 221?
Loctite 221 is designed for locking and sealing threaded fasteners that require easy disassembly with standard hand tools, especially small diameter or long engagement fasteners prone to loosening from vibration.
How long does it take for Loctite 221 to cure?
Fixture cure typically occurs within 15-30 minutes at room temperature (22°C). Full cure can take up to 24 hours, depending on temperature, humidity, and surface preparation.
Can Loctite 221 be used on stainless steel?
Yes, but it may require an activator like Loctite `764` or `7471` to ensure a proper cure on stainless steel and other inactive metals, especially in colder temperatures or when rapid cure is needed.
What is the shelf life of Loctite 221?
When stored properly in its original, unopened container in a cool, dry place, Loctite 221 typically has a shelf life of 2 years from the date of manufacture.
How do I remove a fastener treated with Loctite 221?
Loctite 221 is designed for easy disassembly. Use standard hand tools. If the bond is very tight, gentle heating with a heat gun (up to 200°C or 392°F) can help break the bond before disassembly.
What is the difference between Loctite 221 and higher strength threadlockers?
Loctite 221 is a low-strength threadlocker, ensuring easy removal. Higher strength threadlockers (e.g., Loctite 243, 271) provide a more permanent bond and may require heat or higher force to disassemble, making them suitable for applications where disassembly is infrequent.
Troubleshooting
Threadlocker does not cure
Ensure there is metal-to-metal contact. Clean threads thoroughly. Check if the ambient temperature is too low. Consider using a Loctite activator if working on inactive metals or in cold conditions.
Fastener still loosens
Verify that the correct Loctite product strength was used. Ensure the part was fully assembled and cured. Check for excessive vibration beyond the product's rating.
Difficulty applying due to viscosity
Ensure the nozzle is clear. If the product has been stored for a long time or in cold temperatures, viscosity might increase. Gently warm the bottle if necessary (do not overheat).
Pros and Cons
Pros
- Ensures easy disassembly of small threaded components.
- Prevents loosening from vibration and shock.
- Low viscosity allows for excellent wicking action.
- Cures effectively on most metal surfaces.
- Suitable for general-purpose threadlocking.
Cons
- Requires metal-to-metal contact to cure.
- May not fully cure on passive metals like stainless steel or plated surfaces without an activator.
- Low strength may not be suitable for high-stress applications.
- Curing time can be affected by temperature and surface preparation.
- Not ideal for large diameter fasteners where higher strength is needed.
Setup, Compatibility & Care
Setup:
- Clean Surfaces: Ensure all threads are clean, dry, and free from oil, grease, and other contaminants. For best results, use a suitable cleaner like Loctite `7063` or `7840`.
- Apply Adhesive: Apply a few drops of Loctite 221 to the male thread.
- Assemble Part: Assemble the threaded component and tighten to the desired torque. Ensure metal-to-metal contact.
- Curing: Allow the adhesive to cure. Fixture cure typically occurs within 15-30 minutes at room temperature (22°C). Full cure can take up to 24 hours.
Compatibility:
- Metals: Works best on active metals like brass, copper, and steel. May require an activator (`Loctite `764` or `7471`) on inactive metals such as stainless steel or plated surfaces, or in cold conditions.
- Temperature: Service temperature range is typically -54°C to +150°C (-65°F to +300°F).
Care:
- Storage: Store in a cool, dry place, away from direct sunlight. Keep the cap tightly closed.
- Handling: Avoid contact with skin and eyes. Use in a well-ventilated area. Refer to the Safety Data Sheet (SDS) for detailed handling precautions.