Kester 186-18 Soldering Flux RMA Rosin Solution
Kester 186-18 Soldering Flux (Rosin Flux) is a high-performance liquid flux developed for critical electronic assembly and rework applications. Manufactured by Kester, this specialized rosin flux offers superior wetting activity while maintaining complete non-corrosive safety on circuit assemblies.
Technical Features of Kester 186-18 Soldering Flux
Under the former MIL-F-14256 military standard, Kester 186-18 was QPL approved as Type RMA. Although its fluxing ability approaches that of aggressive Type RA flux, the flux residue remaining after soldering is strictly non-corrosive and non-conductive.
This formulation possesses high thermal stability, making it ideal for soldering multi-layer assemblies that require high preheat temperatures. Exposure to high preheat temperatures does not degrade the solubility of the residue in normal cleaning solvents, and there is zero surface insulation resistance (SIR) degradation caused by the flux residue. Due to the minimal use of ionic activating agents and the inactive nature of the residue, it can be left on circuit board assemblies for many applications, offering built-in moisture and fungus resistance.
Key Product Highlights
- RMA Performance: QPL approved as Type RMA under former MIL-F-14256, delivering fluxing action approaching Type RA.
- High Thermal Stability: Withstands elevated preheat temperatures required for multi-layer PCB processing.
- Solubility Retention: High preheating does not impair residue solubility in standard cleaning solvents.
- Safe Residue Properties: Non-corrosive, non-conductive, moisture-resistant, fungus-resistant, and causes no SIR degradation.
Product Specifications
| Property / Specification | Details |
|---|---|
| Product Name | Kester 186-18 Soldering Flux |
| Military Approval (MIL-F-14256) | Type RMA (QPL approved under former standard) |
| Activity Performance | RMA activity level approaching Type RA fluxing ability |
| Thermal Resistance | High thermal stability for multi-layer assemblies and high preheating |
| Residue Characteristics | Non-corrosive, non-conductive, moisture resistant, fungus resistant, no SIR degradation |
| Primary Application | Soldering difficult assemblies and multi-layer printed circuit boards |
Conclusion
Engineered for high-temperature demands and stringent RMA process requirements, Kester 186-18 Soldering Flux ensures optimal wetting without compromising circuit insulation or reliability. For technical inquiries, datasheets, or purchasing assistance, please visit Contact – LORIOT INDUSTRIAL.

