Product details
| Grade | Loctite 577 |
| Strength | Medium strength |
| Colour | Yellow |
| Family | Thread sealants |
| 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 577 is for
The medium-strength thread sealant, and the one that copes with loose threads — it performs in gaps up to 0.25 mm, where a thinner sealant would simply drain out. It cures on stainless steel without surface activation, and tolerates the cutting and anti-corrosion oils and surfactant-based cleaners left on threads in real workshops.
Key features
- Medium strength — 33 N·m breakaway on M10 steel
- Gap performance to 0.25 mm — suits worn or loose threads
- Cures on stainless steel without activation
- Tolerates cutting, lubricating and anti-corrosion oils and surfactant cleaners
- Thixotropic yellow paste — will not migrate
- Conforms to EN 751-1 class H with DVGW certification
- NSF registered Category P1 for food processing areas (a regional approval)
- Tested to GASTEC QA AR-214 for hydrogen service; cold strength to −75°C
Typical applications
- Pipe threads
- Hydraulics and pneumatics
Technical data
Uncured material
| Technology | Acrylic |
| Chemical type | Dimethacrylate ester |
| Appearance | Yellow paste |
| Fluorescence | Positive under UV light |
| Components | One component — no mixing |
| Cure | Anaerobic; secondary cure by activator |
| Viscosity, Brookfield RVT 25°C | Spindle 6 at 20 rpm: 24,500 mPa·s |
| Viscosity at 2.5 rpm | 100,000 mPa·s |
| Maximum gap | 0.25 mm (0.01 in) |
Breakaway torque by substrate
Cured 24 hours at 22°C, ISO 10964.
| Substrate | Breakaway N·m (lb·in) | Prevail N·m (lb·in) |
|---|
| M10 steel | 33 (295) | 2.5 (22) |
| M10 zinc phosphate | 30 (265) | 1.8 (16) |
| M10 brass | 23 (205) | 1.3 (12) |
| M10 zinc dichromate | 20 (175) | 3.7 (33) |
| M10 stainless steel | 15 (135) | 1.9 (17) |
| M6 steel | 7 (62) | 0.7 (6.2) |
| M16 steel | 69 (615) | 7.5 (66) |
Further strength data
| Breakloose torque, M10 steel, pre-torqued to 5 N·m | 27 N·m (240 lb·in) |
| Breakloose after 1 week, M10 zinc phosphate | 30 N·m (265 lb·in) |
| Compressive shear strength (ISO 10123) | 5 N/mm² (725 psi) |
| Tensile strength (ISO 37) | 1.3 N/mm² (190 psi) |
| Tensile modulus (ISO 37) | 168 N/mm² (24,350 psi) |
| Cold strength | Tested to −75°C |
Chemical resistance
As a percentage of initial strength — note it rises in oil and fuel.
| Environment | °C | 100 h | 500 h | 1,000 h |
|---|
| Motor oil (5W30 synthetic) | 125 | 120% | 130% | 135% |
| Brake fluid (DOT 4) | 22 | 115% | 115% | 120% |
| Unleaded petrol | 22 | 115% | 105% | 105% |
| DEF (AdBlue®) | 22 | 125% | 125% | 130% |
| B100 bio-diesel | 22 | 105% | 115% | 115% |
| Water / glycol 50:50 | 87 | 105% | 95% | 90% |
| Ethanol | 22 | 110% | 90% | 90% |
| Acetone | 22 | 95% | 65% | 70% |
How to use it
- Clean all surfaces, external and internal, with a Loctite cleaning solvent and allow to dry.
- On inactive metals, or if the cure is too slow, spray with Loctite SF 7471 or SF 7649 activator and allow to dry.
- Apply a 360° bead to the leading threads of the male fitting, leaving the first thread free.
- Force the material into the thread roots to fill the voids. On larger threads, apply a 360° bead to the female threads as well.
- Assemble and wrench-tighten in line with the fitting manufacturer's recommendations.
- A properly tightened fitting seals instantly to moderate pressure; allow 24 hours for maximum pressure and solvent resistance.
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.
- Disassembly is with standard hand tools; over 1 in. diameter or long engagement may need localised heat to about 250°C.
- 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.
- For potable water work, wipe away excess uncured product with a lint-free cloth and Loctite SF 7063 or similar.
Loctite 577, 567 or 55?
577 is medium strength with 0.25 mm gap capability — the choice for worn or loose metal threads that should stay sealed and located. 567 is low strength and high lubricity, the anti-galling grade for stainless, and carries NSF 61 potable water certification. 55 is the cord: no cure, instantly pressurisable, adjustable after tightening, and the only one of the three that suits plastic threads.
Always read the current technical and safety data before use —
ask us and we'll send it with your quotation.
