Product details
| Grade | Loctite 515 |
| Strength | Low strength |
| Colour | Purple |
| Family | Flange & gasket 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 515 is for
The general-purpose form-in-place gasket, and the one that flexes with minor flange movement rather than cracking. High viscosity, so it stays put on a vertical face, and it resists low pressure immediately after assembly before it has cured. Henkel names pumps, thermostats, compressors, transmission housings and axle covers as the typical applications. Fluorescent under UV, so a bead can be inspected before the flange goes together.
Key features
- Flexes with minor flange movement instead of cracking
- Resists low pressure immediately on assembly, before curing
- Very high viscosity — stays on vertical and overhead faces
- Fluoresces under UV light for bead inspection
- 14 N/mm² tensile strength on grit-blasted steel
- UL classified (MH8007) for petrol, petroleum oils, natural gas, butane and propane
- Australian Gas Association certificate 2590 Class II, 500 kPa, −10 to 150°C
- Gains strength in motor oil — 165% after 1,000 hours at 125°C
- Cold strength tested to −75°C
Typical applications
- Gearbox covers
- Pump housings
Technical data
Uncured material
| Technology | Acrylic |
| Chemical type | Methacrylate ester |
| Appearance | Opaque dark purple |
| Fluorescence | Positive under UV light |
| Components | One component — no mixing |
| Cure | Anaerobic |
| Viscosity, Brookfield HBT 25°C | Spindle TB at 5 rpm, Helipath: 150,000–375,000 mPa·s |
| Viscosity at 0.5 rpm | 700,000–1,700,000 mPa·s |
| Viscosity class | High |
| Specific gravity at 25°C | 1.1 |
| Ignition temperature (UL) | 467°C |
Strength
Cured at 22°C unless stated.
| Compressive shear strength after 1 h (ISO 10123) | ≥5.0 N/mm² (≥725 psi) |
| Compressive shear strength after 24 h | ≥5.0 N/mm² (≥725 psi) |
| Lap shear strength, grit-blasted steel (ISO 4587) | 6.0 N/mm² (870 psi) |
| Lap shear after 24 h cure at 90°C, tested at 22°C | ≥6.9 N/mm² (≥1,000 psi) |
| Tensile strength, grit-blasted steel (ISO 6922) | 14 N/mm² (2,030 psi) |
| Maximum gap | 0.25 mm |
| Cold strength | Tested to −75°C |
Chemical resistance
Effect of environment on strength, not a measure of sealing performance. Like 518, the petrol figures are poor — this is not the grade for a fuel flange.
| Environment | °C | 500 h | 1,000 h |
|---|
| Motor oil | 125 | 160% | 165% |
| Water / glycol 50:50 | 87 | 80% | 80% |
| DEF (AdBlue®) | 22 | 60% | 60% |
| Petrol | 22 | 20% | 15% |
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) |
| Heat ageing data published at | 100°C, 120°C and 150°C |
| AGA working temperature | −10°C to 150°C |
How to use it
- Flange faces must be clean and free from grease.
- Designed for close-fitting flanged parts with gaps up to 0.25 mm.
- Apply as a continuous bead, a rolled film, or by screen printing to one flange face.
- For gaps over 0.125 mm using a pen roller, apply a rolled film to both faces.
- Low pressure may be applied to confirm the seal immediately after assembly, before curing.
- Tighten the flanges as soon as possible after assembly to avoid shimming.
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.
- Check compatibility if aqueous washing systems are used before bonding; some washes affect the cure.
- 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.
Which flange sealant?
515 is the flexible general-purpose grade — it moves with the flange, and its gas approvals make it the choice on fuel and gas equipment flanges (though not for constant petrol immersion). 574 cures faster and is stronger. 573 cures slowly for large flanges. 518 tolerates oil contamination and bonds well to aluminium. 510 is the high-temperature grade to 200°C. SI 5927 is a silicone for flanges that flex a lot or run to 315°C.
Always read the current technical and safety data before use —
ask us and we'll send it with your quotation.
