Keeps bolts from seizing at high temperature so they can be removed later.
Anti-seize compound is applied to bolt threads to form a high-temperature solid lubricating layer (copper, nickel, aluminum, silver, or PTFE and graphite particles). It stops threads from galling and cold-welding through metal diffusion and oxidation at high temperature, so bolts can be removed at maintenance. Without it, high-temperature bolts often have to be cut off and scrapped.
This page supplies LOCTITE C5-A (copper-based). Other base types are available on request.
Choosing the base
| Item | Copper | Nickel | Silver / PTFE |
|---|---|---|---|
| Color | Copper red | Silver grey | Silver-white / translucent |
| Temperature range | −30 to +1100 °C | −30 to +1400 °C | +260 to +1100 °C |
| Metals | Not for stainless steel (galvanic corrosion) | Wide use, including stainless steel | Copper-free areas (semiconductor) |
| Packing | Brush-top can / spray / stick | Can / stick | Syringe / can |
| Application | Thin, even coat on threads | Same | Same |
| Torque | Reduce tightening torque by 20–25% | Same | Same |
Typical uses
- Semiconductor furnace and oxidation tube flanges (400–1200 °C): fabs usually choose nickel or silver types to avoid copper contamination.
- Boilers and steam lines (200–500 °C): copper or nickel; re-apply at each maintenance.
- Exhaust gas RTOs and scrubbers: nickel on the hot RTO side (800–1000 °C); nickel or PTFE for corrosive scrubbers.
- Exhaust pipes and fan bolts (200–600 °C): copper-based is economical.
Quick selection
| Application | Recommended | Note |
|---|---|---|
| General high-temperature steel bolts | Copper | Economical, widely used |
| Stainless steel bolts | Nickel (not copper) | Copper causes galvanic corrosion |
| Semiconductor furnace tubes | Nickel or silver | Avoids copper contamination of wafers |
| Strongly corrosive chemical service | Nickel or PTFE | Chemical resistance |
| Above 1100 °C | Nickel (to 1400 °C) | Copper no longer usable |
Anti-seize is not threadlocker
| Item | Anti-seize | Threadlocker |
|---|---|---|
| Function | Lubricates, prevents seizing, easy removal | Locks, prevents loosening |
| Form | Paste, does not harden | Liquid, cures anaerobically to a solid |
| Temperature | +260 to +1400 °C | Usually up to about +150 °C |
| Typical use | Exhausts, furnace tubes, hot flanges | Fixing machines and equipment |
Using the wrong one either lets bolts loosen or makes them fail in the heat.
Torque correction
Anti-seize lowers thread friction, so the same torque gives a higher preload and may overstress or break the bolt. For general industrial bolts, reduce torque by 20–25%; for high-pressure or safety-critical joints, use the lubricated K-factor from the technical data sheet and confirm by torque plus angle; for large flanges with hydraulic tensioners, measure preload directly. Coating thickness, evenness, thread size and washers all affect friction — always check the data sheet for critical joints.
Request a quote
Tell us the base type, pack form and quantity. Request a quote →