Loctite SF 7649 Primer & Accelerator Spray & Brush-on Bottles for Threadlockers (variety of sizes)

Product Name: Loctite SF 7649 Primer & Accelerator (Primer N)

Loctite SF 7649 (formerly known as Loctite 7649 or Primer N) is a solvent-based primer and activator designed to promote the curing speed of Loctite anaerobic adhesives and sealants. It is particularly effective on "passive" metals (like stainless steel, aluminum, and plated surfaces) that do not have enough active metal ions to trigger a fast cure on their own. It also speeds up curing on active metals and in cold temperatures.

Popular Applications & Uses
- Priming inactive or passive metal surfaces (stainless steel, aluminum, titanium, galvanized steel) to allow threadlockers to cure.
- Accelerating the cure speed of threadlockers, pipe sealants, gasketing compounds, and retaining compounds.
- Ensuring cure in cold environments (below room temperature).
- Curing adhesives through larger-than-normal bond gaps.
- Speeding up maintenance and repair jobs where rapid return to service is required.

Industries that Commonly Use It
- General Industrial Maintenance and Repair
- Automotive and Transportation
- Heavy Equipment Maintenance
- Marine (due to common use of stainless steel)
- Manufacturing Assembly

Special and Unique Features
- dual-Function: Acts as both a surface primer (for inactive metals) and a cure accelerator (for speed).
- Improves Cure on Passive Metals: Essential for ensuring anaerobic adhesives cure properly on stainless steel, aluminum, and plated parts.
- Cold Weather Curing: Enables curing in temperatures as low as 0°F (-18°C).
- Acetone Base: Fast-drying solvent carrier leaves the active ingredients on the surface quickly.
- Fluorescent: Under UV light, it glows green to allow for visual inspection of coverage.

Key Properties
- Base: Acetone
- Color: Clear Green
- Viscosity: Very Low (2 cP) - *Like water*
- Drying Time: 30 - 70 seconds
- On-Part Life: Up to 30 days (parts can be primed and stored before bonding).
- Specific Gravity: 0.79

Usage Instructions
- Spray or brush onto clean surfaces to be bonded.
- Allow the solvent (acetone) to evaporate (approx. 30-70 seconds) until the surface is dry.
- Apply the Loctite anaerobic adhesive (Threadlocker, Retaining Compound, etc.) to the primed surface and assemble.
- For large gaps, apply primer to both surfaces.

Known backups / known substitutes for this product
- Loctite SF 7471 (Primer T): Similar primer but acetone/isopropanol based, typically used when a slightly longer on-part life is needed or specific spec call-out.
- Permatex Surface Prep Activator for Anaerobics (24163).
- Vibra-Tite 611 Primer/Accelerator.

Comparison Note
- **7649 vs. 7471:** Both are primers for anaerobic adhesives. **7649 (Primer N)** is the most common general-purpose primer. **7471 (Primer T)** is often specified in older military or aerospace specs. 7649 has a longer on-part life (30 days) compared to 7471 (7 days).
- **Primer vs. Accelerator:** In the world of anaerobics, 7649 serves both roles. It "primes" inactive metals that wouldn't otherwise react, and it "accelerates" the reaction on active metals.