---
watermark: ORIRO
disable-model-invocation: true
name: trades-metalworking
provider: ORIRO.ai
copyright: Copyright (c) 2026 ORIRO.ai
description: >
  Metalworking — welding, machining, metal properties, heat treatment, and
  fabrication techniques for hobbyists and professionals. Sources: AWS (American
  Welding Society) fundamentals (free), MIT OCW 2.008 (CC-BY).
---

# Metalworking

## Welding processes

### MIG (GMAW)

Most beginner-friendly. Wire-feed electrode. Continuous arc.
**Settings:** Wire speed + voltage. Hotter = more voltage, faster = more wire.
Gas: 75% Argon/25% CO₂ (C25) for steel. 100% Argon for aluminum.
Good for: Mild steel, sheet metal, automotive repair.

### TIG (GTAW)

Most precise. Separate filler rod fed by hand. Non-consumable tungsten electrode.
**Applications:** Aluminum, stainless steel, exotic alloys.
AC for aluminum, DC- for steel/stainless.
Pedal controls heat. Highest quality welds.

### Stick (SMAW)

Most portable. No gas required. Works on dirty/rusty metal.
Electrode types: 6013 (easy, general), 7018 (structural), 6011 (all-position).
**Good for:** Field repairs, thick steel, construction.

### Welding safety

Auto-darkening helmet minimum shade 10 for MIG, 11-12 for TIG.
Never weld galvanized metal without respirator (zinc fumes toxic).

## Metal properties

**Low carbon steel (A36, 1018):** Easy to weld, machine, and form. Most common.
**Stainless steel (304, 316):** Corrosion resistant. Chrome 18%, Nickel 8%.
**Aluminum (6061-T6):** Lightweight, corrosion resistant. Tricky to weld.
**Tool steel (D2, O1):** High hardness for cutting tools. Requires careful heat treatment.

## Heat treatment

**Annealing:** Heat to critical temperature, slow cool. Softens metal, relieves stress.
**Hardening:** Heat steel + quench (water/oil). Increases hardness.
**Tempering:** After hardening, reheat to lower temperature. Reduces brittleness.
Steel tempering colors: Pale yellow (~425°F), Straw (~450°F), Purple (~510°F), Blue (~570°F).

## Basic machining

**Lathe:** Rotates workpiece. Turn, face, bore, thread.
**Mill:** Rotates cutting tool. Slots, pockets, surfaces.
**Drill press:** Controlled drilling. Use cutting speed chart by material.
**Speeds and feeds:** Higher for soft metals, lower for hard. Tool life vs material removal rate.

Sources: AWS (americanweldingsociety.org — free fundamentals), MIT OCW 2.008 (CC-BY),
Lincoln Electric welding guides (free)