Brazing & Soldering

Brazing and soldering join parts by melting a filler metal below the base metal’s melting point, enabling clean, low-distortion joints and dissimilar-metal assemblies.

Overview

Brazing and soldering are joining processes that bond components using a molten filler alloy that flows by capillary action into a fitted joint, while the base metals stay solid. Brazing runs at higher temperatures than soldering and typically delivers higher joint strength; soldering is common for electronics and thin, heat-sensitive parts.

Choose brazing/soldering when you need low distortion, good cosmetic finish, leak-tight seams, or to join dissimilar metals (for example copper to brass or carbide to steel). Furnace brazing is strong for repeatable, higher-volume assemblies; torch brazing fits lower-volume work and localized heating; wave soldering supports high-throughput PCB assembly.

Tradeoffs: joint strength and temperature capability are usually lower than fusion welding, joint fit-up and cleanliness matter a lot, and fillers/fluxes can drive corrosion or post-cleaning requirements. Qualification often depends on joint design, alloy selection, and process control rather than just operator skill.

Common Materials

  • Copper
  • Brass
  • Low-carbon steel
  • Stainless steel 304
  • Aluminum 6061
  • Nickel alloys

Tolerances

±0.003"

Applications

  • Copper plumbing manifolds and fittings
  • Brazed plate heat exchangers
  • HVAC refrigerant line joints
  • Carbide-to-steel cutting tool tips
  • Automotive radiator and condenser assemblies
  • Wave-soldered printed circuit boards

When to Choose Brazing & Soldering

Choose brazing or soldering for assemblies that can be designed with close joint gaps and benefit from low distortion and clean external appearance. It fits both prototypes and production, especially when you need repeatability across many joints (furnace brazing) or high-throughput electronics assembly (wave soldering). It’s a good match for thin sections, mixed materials, and parts that can’t tolerate melting the base metal.

vs MIG (GMAW)

Choose brazing/soldering when distortion control and appearance matter, or when the base metals are thin and would warp or burn through with arc heat. It’s also a practical option for dissimilar-metal joints where GMAW filler/base compatibility is limiting.

vs TIG (GTAW)

Choose brazing/soldering when you want a low-heat, capillary-fed joint with minimal weld bead and less risk of sensitization or distortion on thin stainless or small assemblies. TIG wins on ultimate joint strength and high-temperature service; brazing wins on fit-and-finish and joining dissimilar combinations.

vs Stick (SMAW)

Choose brazing/soldering for small-to-medium assemblies needing cleaner joints, tighter cosmetic requirements, or less heat input than SMAW typically delivers. Brazing can also be easier to fixture for repeatability in a shop environment versus highly operator-dependent stick weld beads.

vs Resistance Welding

Choose brazing/soldering when you need continuous, leak-tight seams, multiple joints in one thermal cycle (furnace), or you can’t access both sides with electrodes. Resistance welding is best for lap joints and very fast cycle times; brazing fits more joint geometries and dissimilar materials.

vs Adhesive Bonding

Choose brazing/soldering when the joint must conduct heat/electricity, withstand solvents/UV, or tolerate higher service temperatures than most adhesives. Adhesives can simplify surface prep in some cases and handle large bond areas; brazing provides a metallic, inspectable joint and better long-term thermal stability.

Design Considerations

  • Design for capillary flow: use lap or scarf joints and specify a controlled joint gap appropriate to the filler alloy
  • Call out base metal, filler alloy family (e.g., silver-, copper-phos-, nickel-based), and flux/atmosphere requirements to avoid quoting assumptions
  • Provide vent paths and avoid blind cavities to prevent flux entrapment and voids in furnace brazing
  • Minimize large section-thickness mismatches near the joint to reduce differential heating and residual stress
  • Specify post-braze cleaning/passivation needs when flux is used, especially for corrosion-sensitive assemblies
  • Add simple fixturing datums and limit joint count per setup to improve repeatability and reduce rework