Soldering & Brazing

ALWAYS USE LEAD FREE SOLDER!!!!

Soldering

• Soldering: process in which  two or more metal items are joined together by a melting and flowing a filler metal, solder below 842*F, into the joint.

• The filler metal has a lower melting point than the adjoining metal. 

• Soldering differs from welding in that soldering does not involve melting the work pieces.

Soldering Applications• Plumbing, electronics, and metalwork • Commonly used in repairs & joining of dissimilar metals • Plumbing: Soldering provides reasonably permanent but 

reversible connections between copper pipes in plumbing systems 

• Electronics: soldering connects electrical wiring and electronic components to printed circuit boards (PCBs).

• Metalwork: Jewelry repair, sheet metal objects such as food cans, roof flashing, rain gutters.

• Used to seal & repair automobile radiators.• Small mechanical parts are often soldered or brazed as well. • Soldering is also used to join copper foil in stained glass work. 

Applications

Advantages of Soldering• Low power & temperature• Easily automated process• Dissimilar materials may be joined (cast iron & steel)• Thin material parts may be joined• Moderate skill level

Disadvantages of Soldering

• Careful removal of the flux residuals is required in order to prevent corrosion;

• Large sections cannot be joined• Fluxes may contain toxic components• Soldered joints cant be used in high temperature applications

• Low strength of joints.

Soldering Equipment

• Guns, irons, torches, filler

Electrical Soldering Video

• Electrical soldering (4:46)– https://www.youtube.com/watch?v=BLfXXRfRIzY 

• Procedure– Clean soldering iron tip– Allow iron to heat up – Apply small amount of ROSIN core solder to tip–  Heat wire– Apply Solder– Unplug soldering iron

Torch Soldering Video

• Torch Soldering Video– https://www.youtube.com/watch?v=WpHQ0WCDlFI 

• PROCEDURE– Cut pipes to size– Clean or all fittings with wire brush or sand paper–  Apply flux to ALL joints– Heat metal– Apply solder (1” pipe = 1” solder)

Brazing / Braze Welding

• Brazing: high temperature soldering (above 842*F)• Flux coated bronze or brass filler rod used to join work pieces

• The base metal does not melt. 

In the past, nearly all solders contained lead, but environmental concerns have increasingly dictated use of lead-free alloys for electronics and plumbing purposes

Advantages of Brazing

• It's easy to learn.• You can join virtually any dissimilar metals.• Repair cast iron• The bond line can be very neat in appearance.• Joint strength is strong enough for most non-

heavy-duty use applications

Disadvantages of Brazing• A poor joint/weak joint may be hard to identify• Long-term effects of dissimilar metals • Filler color may differ from base metal• Low melting point…brazed parts may not be used in high temperature applications. (e.g. exhaust manifold)

Brazing Video

• Brazing Video (8 minutes)– https://www.youtube.com/watch?v=0fly4f0STGw

• Procedure – Thoroughly clean metal– Evenly preheat metal – Apply brazing rod to metal– Air cool– Remove glass slag