Welding and Soldering for Sheet Metal Flashcards

What is TIG welding and when is it preferred for sheet metal work?

Answer: Gas Tungsten Arc Welding using a non-consumable tungsten electrode, preferred for precision work on stainless steel and aluminum

TIG (GTAW) welding uses a non-consumable tungsten electrode with separate filler rod and argon shielding gas. It provides superior control and weld quality, making it ideal for stainless steel, aluminum, and critical applications.

What is the correct procedure for cleaning a joint before soldering?

Answer: Remove all dirt, grease, oxides, and coatings from the joint area using mechanical cleaning or chemical flux

Proper soldering requires clean surfaces free of dirt, grease, and oxides. Mechanical cleaning (wire brush, sandpaper, emery cloth) and/or chemical flux removes contaminants to allow proper solder wetting and adhesion.

What is a 'soldering copper' (soldering iron) and how is it used in sheet metal work?

Answer: A heavy copper-tipped tool heated to transfer heat to the joint for melting solder in flat seam work

A soldering copper is a heavy, copper-tipped tool that stores and transfers heat to the sheet metal joint. The copper tip is tinned (coated with solder) and used to heat the seam and flow solder into flat lock and other seams.

What shielding gas is used for TIG welding aluminum sheet metal?

Answer: Pure argon (100%)

Pure argon is the standard shielding gas for TIG welding aluminum. It provides good arc stability, proper cleaning action on the aluminum oxide layer, and excellent shielding of the weld puddle from atmospheric contamination.

What is the purpose of 'tinning' a soldering copper tip?

Answer: To coat the tip with a thin layer of solder that promotes heat transfer and prevents oxidation of the copper

Tinning coats the copper tip with solder, which improves heat transfer to the workpiece, prevents the copper from oxidizing (which would reduce heat transfer), and helps the solder flow smoothly from the tip.

What weld joint type is most commonly used for longitudinal seams on welded duct?

Answer: Lap joint or corner joint

Lap joints and corner joints are the most common for welded duct longitudinal seams. Lap joints provide good strength and are easier to fit up on sheet metal gauges. Corner joints are used on rectangular duct corners.