Product details
| Grade | Loctite 620 |
| Strength | High strength |
| Colour | Green |
| Family | Retaining compounds |
| 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 620 is for
The high-temperature retaining compound, and the numbers make the case on their own: 17 N/mm² cured at room temperature, rising to 24 N/mm² after 24 hours at 177°C. It gets stronger in service rather than weaker. Henkel names locating pins in radiator assemblies and bearings in auto transmissions — hot assemblies where an ordinary grade would soften.
Key features
- High temperature — strength rises from 17 to 24 N/mm² after heat
- Hot strength plotted to 250°C, heat ageing data to 180°C
- Gaps approaching 0.2 mm
- High viscosity at 8,500 mPa·s — stays in the joint
- Full strength retained in motor oil at 125°C and brake fluid to 1,000 hours
- Elongation at break under 1% — a rigid, load-bearing bond
Typical applications
- Hot bearings
- Rotors and impellers
Technical data
Uncured material
| Technology | Acrylic |
| Chemical type | Methacrylate ester |
| Appearance | Green liquid |
| Components | One component — no mixing |
| Cure | Anaerobic; secondary cure by activator |
| Viscosity, Brookfield RVT 25°C | Spindle 5 at 20 rpm: 8,500 mPa·s |
| Viscosity, EN 12092 MV 25°C | 1,800 mPa·s at 129 s⁻¹ |
| Viscosity class | High |
| Specific gravity at 23°C | 1.16 |
Strength
Steel pins and collars, ISO 10123.
| Compressive shear strength after 24 h at 23°C | 17 N/mm² (2,500 psi) |
| After a further 24 h at 177°C, tested at 23°C | 24 N/mm² (3,500 psi) |
| Elongation at break (ISO 37) | <1% |
| Maximum gap | Approaching 0.2 mm |
| Hot strength plotted to | 250°C |
| Heat ageing data published at | 120°C, 150°C and 180°C |
Chemical resistance
As a percentage of initial strength after ageing.
| Environment | °C | 100 h | 500 h | 1,000 h |
|---|
| Motor oil | 125 | 100% | 100% | 100% |
| Brake fluid | 22 | 100% | 100% | 100% |
| Unleaded petrol | 22 | 95% | 95% | 95% |
| Acetone | 22 | 95% | 95% | 95% |
| Water / glycol 50:50 | 87 | 95% | 80% | 80% |
| Ethanol | 22 | 100% | 100% | 75% |
Cured material
| Coefficient of thermal expansion (ISO 11359-2) | 80 × 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 surfaces, external and internal, with a Loctite cleaning solvent and allow to dry.
- On inactive metals, or where large gaps are present, use an activator and allow to dry.
- Slip fits: apply around the leading edge of the male part and the inside of the female part, and use a rotating motion during assembly to spread it.
- Press fits: apply thoroughly to both surfaces and assemble at high press-on rates.
- Shrink fits: coat to a smooth even film. Heating the female part — coat the male. Cooling the male part — coat the female. Doing both — apply to the cooled part, and avoid condensation on it.
- Do not disturb the parts until handling strength is reached.
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.
- Store unopened and dry, ideally 8°C to 21°C; outside 8–28°C the properties can be affected.
- Do not return decanted product to the original container.
- Disassembly: hand tools first, then localised heat to about 300°C — higher than the other grades in this family — and take apart while hot.
Loctite 620 or 638?
Both are strong gap-filling grades. The deciding factor is heat: 620 gains strength after 24 hours at 177°C and its data runs to 250°C, while 638 has a glass transition of 76°C and is characterised to 180°C. Hot assembly — transmission bearing, radiator pin, exhaust-side housing — specify 620. Room temperature with a worn fit — 638 is stronger at 29 N/mm² and fills a slightly larger gap.
Always read the current technical and safety data before use —
ask us and we'll send it with your quotation.
