Last reviewed: May 2026 · MLC editorial team · UK trade workshop perspective
Photo by Steven Purdy on Pexels
Loctite is to threadlockers what Hoover is to vacuum cleaners - the brand name has replaced the category name. But Loctite is also a real product range with specific strength grades and temperature ratings, and choosing the wrong one means either vibration loosening (too weak) or unable to disassemble (too strong). In UK workshops, you'll find three main categories: low-strength blue for easy removal, medium-strength red for most applications, and high-strength purple for permanent joints. Prices range from £2 to £10 per tube depending on the brand and volume. Whether you're dealing with engine components or fasteners in a harsh environment, picking the right threadlocker is critical for reliability and maintenance efficiency.
How we picked these
- Strength grade: low (222) for adjustment screws, medium (243) for fasteners up to M20, high (271) for studs and permanent assemblies.
- Temperature: standard grades to 150°C, high-temp grades (277, 263) to 230°C.
- Cure: 24 hours full cure on degreased steel. Stainless and zinc need primer or 7910 activator to cure.
- Pre-applied: Tuflok or Long-Lok pre-applied is for OEM assembly, not retrofit.
- Anaerobic vs UV: most threadlockers are anaerobic (cure in absence of air). UV threadlockers exist for specific applications.
Reviewed picks
Loctite 243 (Medium Strength, 50ml)
Price: £18-£28 | Best for: general-purpose workshop fastener locking
Loctite 243 is a medium-strength threadlocker in a 50ml bottle, priced between £18 and £28. Ideal for general workshop use on steel and brass fasteners, it's oil-tolerant and cures within 24 hours. A downside is its unsuitability for large studs over M20.
| Strength | Medium (12 Nm break-loose on M10) |
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| Temp | -55 to +150°C |
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| Cure | 24h on steel, faster with primer |
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| Substrate | Steel, brass, oily fasteners |
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| Bottle | 50ml |
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Pros
- Most-used threadlocker grade
- Oil-tolerant - cures on slightly oily threads
- Removable with hand tools when needed
Cons
- Not suitable for studs above M20
- Standard temp only
Check Loctite 243 (Medium Strength, 50ml) on Amazon UK →
Loctite 271 (High Strength, 50ml)
Price: £20-£32 | Best for: studs, permanent assemblies, large fasteners
Loctite 271 High Strength threadlocker is a staple in UK workshops for its robust hold on large fasteners and studs up to M16+. At £20-£32 per 50ml bottle, it offers excellent shock resistance but demands precise application on degreased threads. Removing it requires heat around 250°C and disassembly, making field fixes tricky.
| Strength | High (35 Nm break-loose on M10) |
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| Temp | -55 to +150°C |
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| Cure | 24h on steel |
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| Substrate | Steel - requires degreased threads |
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| Bottle | 50ml |
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Pros
- High strength for studs M16+
- Resists shock and vibration
- Industry-reference high-strength grade
Cons
- Removal requires heat (~250°C) and hand tools
- Not removable in the field without disassembly
Check Loctite 271 (High Strength, 50ml) on Amazon UK →
Loctite 222 (Low Strength, 50ml)
Price: £18-£28 | Best for: adjustment screws, calibration screws, small fasteners
Loctite 222 is a low-strength threadlocker for small fasteners priced between £18 and £28. Ideal for adjustment screws where field adjustments are necessary, it cures in 24 hours on steel and operates from -55 to +150°C. A drawback is its limited use above 10Hz vibration levels.
| Strength | Low (4 Nm break-loose on M10) |
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| Temp | -55 to +150°C |
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| Cure | 24h on steel |
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| Substrate | Steel, brass - adjustment screws |
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| Bottle | 50ml |
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Pros
- Low strength allows field adjustment
- Standard for instrumentation and grub screws
- Removable with hand tools
Cons
- Insufficient strength for vibration above ~10Hz
- Not for structural fasteners
Check Loctite 222 (Low Strength, 50ml) on Amazon UK →
Loctite 277 (High Temp High Strength, 50ml)
Price: £32-£45 | Best for: engine, exhaust, high-temperature fasteners
Loctite 277 is a high-temp threadlocker for serious applications, priced between £32 and £45 per bottle. Ideal for engines and exhaust systems, it boasts a temperature range of -55 to +230°C, making it perfect for manifold work. Offering a break-loose torque of 28 Nm on M10, its high strength suits structural use. However, the premium price tags it as a niche product compared to similar offerings like Loctite 271.
| Strength | High (28 Nm break-loose on M10) |
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| Temp | -55 to +230°C |
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| Cure | 24h on steel |
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| Substrate | Steel, suitable for engine + exhaust |
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| Bottle | 50ml |
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Pros
- 230°C temperature rating - engine + manifold work
- High strength for structural use
- Same chemistry as 271 with high-temp additive
Cons
- Premium price vs 271
- Niche use case
Check Loctite 277 (High Temp High Strength, 50ml) on Amazon UK →
Permatex Threadlocker Blue 24240 (50ml)
Price: £15-£22 | Best for: US-brand alternative to Loctite 243
Permatex Threadlocker Blue 24240 (50ml) is a medium-strength option for steel and brass substrates, withstanding temps from -54 to +149°C. It cures in 24 hours and costs £15-£22. Ideal as an affordable US alternative to Loctite 243, though less recognised in UK workshops and has longer lead times due to sourcing from the US.
| Strength | Medium (equivalent to Loctite 243) |
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| Temp | -54 to +149°C |
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| Cure | 24h |
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| Substrate | Steel, brass |
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| Bottle | 50ml |
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Pros
- Permatex US trade brand
- Equivalent spec to Loctite 243
- Sub-£22 pricing
Cons
- Less UK trade recognition than Loctite
- Australian / US sourcing means longer parts lead times
Check Permatex Threadlocker Blue 24240 (50ml) on Amazon UK →
Rocol Threadlocker Multi-grade kit
Price: £40-£60 | Best for: workshop sample kit for occasional use
The Rocol Threadlocker Multi-grade kit packs low, medium, and high grades in three 10ml bottles for occasional use, ideal for UK workshops needing samples of each grade without waste. At £40 to £60, it’s pricey per millilitre compared to larger singles but handy for variety.
| Set | Low + medium + high grade in 10ml bottles |
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| Temp | Standard range |
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| Use | Sample / occasional use |
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| Bottle | 3 x 10ml |
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Pros
- All three grades in one kit
- Rocol UK brand
- 10ml bottles avoid waste
Cons
- Small bottles - not for daily use
- Per-ml cost higher than 50ml singles
Check Rocol Threadlocker Multi-grade kit on Amazon UK →
Recommendations at a glance
| Best general-purpose | Loctite 243 - medium strength, oil-tolerant, removable |
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| Best for studs / permanent | Loctite 271 - high strength for M16+ structural |
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| Best for adjustment screws | Loctite 222 - low strength, field-adjustable |
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| Best for high-temperature | Loctite 277 - 230°C for engine and exhaust |
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| Best US-brand alternative | Permatex Threadlocker Blue 24240 - 243-equivalent |
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| Best sample kit | Rocol Multi-grade - three grades in 10ml bottles |
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Related reference on MLC
Frequently asked questions
Loctite 243 vs 271 - which do I need?
243 (medium, blue) for most fasteners M5-M20 in regular use - vehicles, machinery, fasteners that may need future disassembly. 271 (high, red) for studs, large structural bolts M16+, anchor bolts, and assemblies that will not be disassembled. Loctite 243 covers ~80% of workshop use; 271 for the structural 20%.
Do I need to degrease threads before applying threadlocker?
For 271 (high strength) - yes, otherwise cure is unreliable. For 243 (medium) - preferred but not strictly required, the 'oil-tolerant' chemistry will cure on lightly oiled threads. For 222 (low) - light oil is fine. Always degrease with brake cleaner or acetone for critical applications.
Will threadlocker work on stainless / aluminium / zinc?
Stainless steel, zinc-plated, cadmium and aluminium are 'inactive' substrates - threadlocker won't cure reliably without a primer. Loctite 7649 or 7471 activator brushed on first solves this. Plain steel and brass are 'active' substrates and cure normally.
How do I remove a threadlocker'd bolt?
243 (medium): hand tools alone, may need a sharp shock. 271 (high): localised heat to ~250°C (propane torch) softens the locker, then hand tools. 277 (high-temp): heat to 290°C+ required. Never use heat near fuel lines, paint, plastics, or alloy castings.
Do anti-vibration washers work as well as threadlocker?
Different mechanisms. Nordlock or Schnorr washers grip mechanically and tolerate disassembly + reassembly. Threadlocker is single-use (re-application needed on disassembly). For vibration-critical assemblies that may be serviced, Nordlock washers are arguably better. For one-time assembly, threadlocker is simpler.
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