Product details
| Grade | Loctite 241 |
| Strength | Medium strength |
| Colour | Blue |
| Family | Threadlockers |
| Brand | Loctite (Henkel) |
| Stock | Held in Dubai — buy one or bulk |
Pack sizes
Prices on request. Tell us the quantity you need.
Check stockWhat Loctite 241 is for
The medium-strength blue grade aimed at less active substrates — stainless steel, and coated surfaces such as zinc-flake or zinc plated — where the fastener still has to come apart with hand tools for servicing. Lower viscosity than 242 or 243, so it penetrates finer threads.
Key features
- Medium strength — 11.5 N·m breakaway on M10, hand-tool removable
- Formulated for stainless, zinc-flake and zinc-plated fasteners
- Low viscosity: 110–150 mPa·s
- 10 MPa static shear strength on steel pins and collars
- Tested to the lot requirements of Mil-S-46163A (a regional approval)
- 90% of initial strength retained in motor oil at 125°C after 1,000 hours
Typical applications
- General assembly
- Pumps and motors
Technical data
Uncured material
| Technology | Acrylic |
| Chemical type | Methacrylate ester |
| Appearance | Blue opaque liquid |
| Fluorescence | Positive under UV light |
| Components | One component — no mixing |
| Cure | Anaerobic; secondary cure by activator |
| Viscosity at 25°C (Cannon Fenske #300) | 110–150 mPa·s |
| Specific gravity at 25°C | 1.06 |
| Flash point | >93°C — see SDS |
Torque and strength
After 24 hours at 22°C unless stated.
| Breakaway torque, M10 steel (MIL-S-46163) | 11.5 N·m |
| Prevail torque, M10 steel | 10 N·m |
| Break torque, 3/8 × 16 steel | 11.3–22.6 N·m |
| Break torque, 3/8 × 16 zinc or cadmium | 3.4–22.6 N·m |
| Break torque after 90 minutes, 3/8 × 16 steel | 5.6–22.6 N·m |
| Static shear strength (MIL-R-46082) | 10 MPa |
Chemical resistance
As a percentage of initial strength after ageing.
| Environment | °C | 100 h | 500 h | 1,000 h |
|---|
| Motor oil (MIL-L-46152) | 125 | 95% | 90% | 90% |
| Unleaded petrol | 22 | 95% | 90% | 90% |
| Ethanol | 22 | 100% | 100% | 95% |
| Brake fluid | 22 | 95% | 95% | 95% |
| 1,1,1-Trichloroethane | 22 | 100% | 100% | 100% |
| Water / glycol 50:50 | 87 | 85% | 85% | 85% |
Cured material
| Coefficient of thermal expansion (ISO 11359-2) | 100 × 10⁻⁶ K⁻¹ |
| Thermal conductivity (ISO 8302) | 0.1 W/(m·K) |
| Specific heat | 0.3 kJ/(kg·K) |
How to use it
- Clean all threads, internal and external, with a Loctite cleaning solvent and allow to dry.
- Shake the bottle thoroughly before use.
- Do not let the nozzle touch metal — it makes the product cure in the tip.
- Thru holes: apply several drops onto the bolt at the nut engagement area.
- Blind holes: apply several drops down the internal threads to the bottom of the hole.
- Sealing: apply a 360° bead to the leading male threads, leaving the first thread free, and work it into the thread roots.
- Assemble and tighten to the specified torque within the fixture time.
Handling and storage
- Not recommended for pure oxygen or oxygen-rich systems.
- Not a sealant for chlorine or other strong oxidising materials.
- Not normally recommended on plastics — thermoplastics can stress-crack.
- On passive metals (stainless, aluminium, plated) or below 5°C, use Loctite SF 7471 or SF 7649 activator to bring the cure speed up.
- Store unopened and dry. Henkel gives optimal storage as 8°C to 21°C; outside 8–28°C the product properties can be affected.
- Do not return decanted product to the original container.
Loctite 241, 242 or 243?
All three are medium-strength blue grades removable with hand tools. 241 is the thinnest and is aimed at stainless and zinc-flake coated fasteners. 242 is the classic thixotropic grade for plated surfaces. 243 is the most capable — oil tolerant, cures on passive substrates, and roughly double the breakaway torque of 241 at 22 N·m on M10. If in doubt, 243.
Always read the current technical and safety data before use —
ask us and we'll send it with your quotation.
