Loctite 242 Medium Strength Threadlocker 50ml
Available
Loctite 242 is a one-component, blue, medium strength anaerobic threadlocker. It locks and seals threaded fasteners that need normal disassembly with standard hand tools.
It is suitable for less active substrates such as plated surfaces, and the blue liquid fluoresces under UV light. Henkel tests it to the lot requirements of Mil-S-46163A.
Where this product is used
- Threaded fasteners that need normal disassembly with standard hand tools
- Plated surfaces and other less active substrates
- Fasteners exposed to motor oil, unleaded gasoline, brake fluid or ethanol (see the Henkel resistance data)
- Locking and sealing threaded fasteners where Mil-S-46163A lot testing is specified (regional approval)
Features
- Medium strength, removable with standard hand tools
- One component, no mixing
- Blue liquid with positive fluorescence under UV light
- Anaerobic cure, with an activator as secondary cure
- Hot strength tested from 0 to 150 °C
- Heat-ageing data at 100, 120 and 150 °C up to 5,000 hours
Key specifications
| Specification | Detail |
|---|---|
| Chemical type | Dimethacrylate ester |
| Colour | Blue liquid, fluorescence positive under UV light |
| Viscosity (Brookfield RVF, spindle 3, Helipath, 25 °C, 20 rpm) | 800 to 1,600 mPa·s |
| Viscosity (Brookfield RVF, spindle 3, Helipath, 25 °C, 2 rpm) | At least 5,000 mPa·s |
| Specific gravity | 1.1 at 25 °C |
| Breakaway torque (3/8 x 16 steel nuts grade 2, bolts grade 5, 24 h at 22 °C, ISO 10964) | 7.9 to 17 N·m |
| Breakaway torque (3/8 x 16 steel, 1 h at 22 °C) | 5.6 to 17 N·m |
| Breakaway torque (M10 black oxide) | 8 to 19 N·m |
| Prevail torque (3/8 x 16 steel, 24 h at 22 °C) | 2.8 to 6.8 N·m |
| Hot strength | Tested 0 to 150 °C |
| Secondary cure | Activator (SF 7471 or SF 7649) |
| Specification (regional approval) | Mil-S-46163A, tested to lot requirements |
| Storage | 8 °C to 21 °C, unopened, dry |
| Technical data sheet | Henkel TDS February 2022 (Reference 1.7) |
Selecting the right option
Loctite 242 is a medium strength grade. For a similar medium strength grade that tolerates minor oil contamination see Loctite 243 Medium Strength Threadlocker. For low strength see Loctite 222 Low Strength Threadlocker; for high strength see Loctite 263 High Strength Threadlocker.
Using it
Use activator SF 7471 or SF 7649 if the metal is inactive or the cure is too slow.
Cure speed depends on the materials, the gap and the temperature; the cure-speed graphs are in the Henkel data sheet.
Remove with standard hand tools.
Storage and handling
Store unopened in a dry location. Optimal storage is between 8 °C and 21 °C. Storage below 8 °C or above 28 °C can adversely affect the properties of the product.
Limits and safety
Not recommended for pure oxygen or oxygen-rich systems, or as a sealant for chlorine or other strong oxidising materials. Plastics can stress crack. The Henkel data sheet states no operating temperature range and no cold-strength figure. Read the safety data sheet before use.
Frequently asked questions
What strength is Loctite 242?
Medium. Henkel designs it for fasteners that need normal disassembly with standard hand tools.
What is the breakaway torque of Loctite 242?
7.9 to 17 N·m on 3/8 x 16 steel nuts (grade 2) and bolts (grade 5) after 24 hours at 22 °C (ISO 10964). On M10 black oxide it is 8 to 19 N·m.
Is Loctite 242 military approved?
Henkel states it is tested to the lot requirements of Mil-S-46163A. This is a regional approval.
When do I need an activator with Loctite 242?
If the metal is inactive or the cure is too slow. Henkel names activator SF 7471 or SF 7649.
What fluids does Loctite 242 resist?
Henkel reports 100% of initial strength after 1,000 hours in motor oil at 125 °C and in brake fluid at 22 °C, and 95% in unleaded gasoline and ethanol at 22 °C.
What temperature can Loctite 242 handle?
The data sheet states no operating range. Hot strength was tested from 0 to 150 °C and heat ageing at 100, 120 and 150 °C.
Related products
See also: Loctite 243 Medium Strength Threadlocker, Loctite 222 Low Strength Threadlocker, Loctite 263 High Strength Threadlocker, Loctite 290 Medium to High Strength Threadlocker, Loctite 248 Medium Strength Threadlocker Stick 19g.
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