Specialty Fabrication
Kitchen exhaust hoods, grease ducts, stainless steel work, soldering, welding, and architectural sheet metal.
- Describe soldering and welding techniques for sheet metal
- Explain kitchen exhaust hood and grease duct requirements
- Identify access door requirements and specialty fabrication methods
Leçon 1
Soldering & Welding Sheet Metal
Soldering Sheet Metal
Soldering joins sheet metal pieces using a filler metal (solder) with a melting point below 840F (450C). The base metal does not melt. Soldering is used for waterproof joints in gutters, flashing, and copper work. The joint gets its strength from capillary action drawing solder into the gap between the mating surfaces.
Solder Types
| Solder | Composition | Application |
|---|---|---|
| 50/50 | 50% tin, 50% lead | General purpose (not for potable water) |
| 95/5 | 95% tin, 5% antimony | Lead-free for potable water contact |
| Silver solder | Silver alloy | High-strength, stainless steel |
Lead-Free Requirement
Lead-containing solder is prohibited for any surface that contacts potable (drinking) water. This includes water tanks, food service equipment, and any component of a potable water system. Use 95/5 or silver solder for these applications.
Welding Sheet Metal
Sheet metal welding uses TIG (GTAW) or MIG (GMAW) processes. TIG welding provides the cleanest, most precise welds and is preferred for stainless steel and visible architectural work. MIG welding is faster and used for heavier gauge material and structural connections. Spot welding joins overlapping sheets without filler metal.
Soldering joins sheet metal below 840F using capillary action - always heat the base metal, not the solder. Lead solder is prohibited for potable water contact. TIG welding is preferred for stainless steel and precision work; MIG welding is faster for heavier gauges.