





The RELIFE RL-403S Medium Temperature (183°C / 10cc) Syringe Solder Paste is an ergonomic, zero-waste micro-soldering solution engineered specifically for mobile phone motherboard repair, BGA reballing, and high-precision SMD point dispensing. Unlike traditional tub-based solder pastes that dry out when exposed to air and require separate spatulas, the RL-403S comes pre-packaged in a sealed 10cc syringe barrel complete with an ergonomic push plunger and interchangeable needle tips, delivering pinpoint application directly to fine-pitch solder pads.
Formulated around an industry-standard Sn63/Pb37 eutectic alloy with a sharp melting threshold of 183°C, this medium-temperature paste ensures rapid, uniform wetting and high-strength metallurgical bonding without subjecting delicate ICs to excessive heat. Its refined Type 4 powder (20–38 µm) micro-spheres eliminate clogging inside narrow dispensing nozzles and prevent solder bridging on tightly spaced CPU, baseband, and power management IC (PMIC) pads.
Key Capabilities & Engineering Features
- Precision Syringe Dispenser with Pusher: Eliminates paste waste and bench mess. The included plunger and needle nozzles allow technicians to deposit microscopic dots directly onto component pads, jumper wires, or stencil apertures with one-handed control.
- Stable 183°C Eutectic Melting Point: Sharp solid-to-liquid transition provides predictable reflow cycles, eliminating pasty intermediate states and preventing cold solder joints during hot-air rework.
- Extended Open-Air Wetting Retention: Engineered with active anti-drying agents—maintains consistent viscosity and workable tackiness on the bench without skinning over or hardening.
- High-Purity Type 4 Particle Profile (20–38 µm): Uniform spherical tin-lead alloy particles ensure smooth extrusion through fine-gauge needles and clean filling into micro-stencil cutouts.
- Strong Deoxidation & Active Wetting: Dissolves oxide films on copper, nickel, and gold surfaces instantly, producing bright, full, and highly conductive solder joints with minimal spatter.
- Clean, Non-Corrosive Mild Residue: Leaves high-impedance, transparent residue that does not induce electrical leakage or corrode motherboard traces. Cleans away effortlessly with standard PCB cleaner or 99% isopropyl alcohol (IPA).
Technical Specification Matrix
Parameter Profile | Specification Details |
Brand & Model | RELIFE RL-403S |
Packaging Type | 10cc Syringe Barrel with Manual Pusher & Dispensing Needles |
Alloy Composition | Sn63 / Pb37 (63% Tin, 37% Lead) |
Melting Temperature | 183°C (361°F) Eutectic |
Particle Size Grade | Type 4 (20–38 µm) |
Volume Capacity | 10cc |
Viscosity Index | 160–230 Pa·s (Optimized for nozzle extrusion & stencil squeegee) |
Optimal Reflow Temperature | 200°C – 220°C (Hot-air rework station nozzle setting) |
Storage Temperature | 0°C – 10°C (Refrigerated) for maximum shelf life; bring to room temp before opening |
Target Applications | Smartphone CPU/NAND BGA reballing, FPC connector pin soldering, PCB jumper wire anchoring |
Dual-Use Bench Workflow Guide
Method A: Direct Point-Dispensing (Jumper Wires & FPC Connectors)
- Remove the protective front plug from the syringe and twist on the desired gauge needle tip.
- Insert the rear plunger pusher into the back of the syringe tube.
- Gently press the plunger to dispense microscopic dots of paste directly onto small solder pads, broken trace jumpers, or battery connector terminals.
- Touch the joint with a micro-soldering iron tip or warm briefly with hot air (280°C–300°C on low airflow) to instantly form a bright, solid connection.
Method B: Stencil Reballing (BGA Chips)
- Depress the plunger to extrude a small bead of RL-403S directly onto the surface of a direct-heat or magnetic reballing stencil.
- Use a flat micro-soldering scraper to spread the paste across all apertures in a single firm 45-degree pass.
- Apply hot air evenly in circular motions until the paste reflows into shiny, uniform solder spheres across the entire BGA ball grid.
- Allow the chip to cool, release it from the stencil, and wipe clean with PCB cleaner.
Package Contents:
- 1 × RELIFE RL-403S 183°C Solder Paste (10cc Syringe)
- 1 × Ergonomic Manual Plunger Pusher
- 2 × Precision Dispensing Needle Tips (Assorted Gauges)
















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