Codeape: Amateur welding course by an amateur

http://www.weldingtipsandtricks.com/cutting-torch.html

http://www.stanford.edu/group/prl/prl_site/Content/Foundry_Area/Welding/Oxyacetylene.html

Lighting the flame

Open the main valve on the acetylene tank ~1/2 turn. This charges the pressure regulator at the top of the tank.
Open the pressure regulator valve on the acetylene tank (turn clockwise to open) and adjust the pressure in the acetylene line to 5 psi. DO NOT pressurize the acetylene over 15 psi - it will explode!
Open the acetylene pin valve on the handle of the welding tool, letting acetylene escape. Tweak the pressure regulator valve until the regulator pressure is constant at 5 psi. Close the acetylene pin valve.
Open the main valve on the oxygen tank. Turn the valve until it is fully open (until it stops turning).
Open the pressure regulator valve on the oxygen tank (turn clockwise to open) and adjust the pressure in the oxygen line to 10 psi.
Open the oxygen pin valve on the handle of the welding tool, letting oxygen escape. Tweak the pressure regulator valve until the regulator pressure is constant at 10 psi. Close the oxygen pin valve.
Slightly open the acetylene valve (~1/8), until you can just barely hear acetylene escaping.
Make sure there is no person or anything flammable in the path of the nozzle. Use the striker to ignite the acetylene. The flame should be yellow/orange and will give off a lot of soot.

Adjusting the flame

Open the acetylene valve further and watch the flame near the nozzle tip. Add more acetylene until the flame is just about to separate from the tip. (The flame will separate from the tip of the nozzle if you add too much acetylene.) If so, reduce the flow until the flame reattaches to the tip, and then open the valve again to the near-separation point. (Another method is to adjust the flow until it just turns turbulent.)
Slightly open the oxygen pin valve. If the flame goes out, turn off the gases and try again. DO NOT try and ignite the flame with both oxygen and acetylene pin valves open. As the oxygen is added the flame will turn bluish in color.
The blue flame will be divided into 3 different color regions - a long yellowish tip, a blue middle section, and a whitish-blue intense inner section. There are three types of flames as described below :
- Neutral - This type of flame is the one you will use most often in the shop. It is called "neutral" because it has no chemical effect upon the metal during welding. It is achieved by mixing equal parts oxygen and acetylene and is witnessed in the flame by adjusting the oxygen flow until the middle blue section and inner whitish-blue parts merge into a single region.
- Reducing flame - If there is excess acetylene, the whitish-blue flame will be larger than the blue flame. This flame contains white hot-carbon particles, which may be dissolved during welding. This "reducing" flame will remove oxygen from iron oxides in steel.
- Oxidizing flame - If there is excess oxygen, the whitish-blue flame will be smaller than the blue flame. This flame burns hotter. A slightly oxidizing flame is used in brazing, and a more strongly oxidizing flame is used in welding certain brasses and bronzes

TOPICS

- Safety

- Regulators

- Long sleeves, flame retardant

- Quick shutoff of fuel

- Tunnel vision

- Fire extinguisher

REMINDERS

- Well ventilated. Fumes from torch. The burning. Any other gas buildups.

- Galvanized (or any coating for that matter) fumes poisonous

- Drums and other small spaces. Sealing things up. Collected and escaping gases

- Cleaner the better- oils, dirt, rust, coating