Gas Welding

Brazing

-Adhesion: filler metal is melted at a lower melting temp onto the base metal Sticks the metal together.

Welding

-Base metal is melted along the weld and filler rod is added- melted metal flows together and becomes solid. FUSION!

Safety Equipment

-Safety glasses, welding visor: # 3-4 lens, gloves, long sleeves.

Welding Equipment

-Torch- tips- hoses- tanks- regulators- tip cleaner- striker

Pressures for welding

-oxygen: 10 psi-Acetylene: 5 psi

Advantages for Gas Welding

-Stronger than brazing-Able to weld thin metal-Not as much sparks/spatter-Do not need electricity

Disadvantages of Gas welding

-Harder to do than Arc welding (Add rod with other hand)

-Not as strong as Arc weld-Can be dangerous

Oxygen Acetylene Equipment

• Oxygen = Green• Acetylene = Red

Neutral Flame

• Neutral Flame– Used in brazing and OAW (oxygen acetylene

welding)– Equal amounts of oxygen and acetylene

Oxygen Tank

• Holds Oxygen• Green• Full tank = 2200 psi

Acetylene Tank

• Holds Acetylene• Red or Blue• Full tank = 250 psi

Tank Valves

• Open and close tanks• Open oxygen tank all the way• Open acetylene tank no more than 1 turn

Regulators

• Attached to tank valve• Used to deliver low pressure to torch• 2 gauges: tank pressure / line pressure

Hoses

• Attached to regulators• Red = Acetylene• Green = Oxygen• Deliver gases to torch

Torch

Attached to hosesMixes the gasesProvides a handle to hold the torch and control

the flame

Torch Valves

• Used to adjust the flame• Righty tighty / Lefty loosy

Torch Tip

• Various sizes• 00 – 5• Higher the number, bigger/hotter flame• We will use 0 or 1

Safety Equipment

-Gloves-Face shield # 3 lens-Leather jacket-Leather apron

Striker

-used to light the torch-Never use a match-Never use a lighter (unless you want to blow your hand off…)-Never light off of another torch

Lighting and adjusting a torch

1-Open Acetylene valve a crack - ¼ turn2-Use striker to ignite3-Open Acetylene valve till the end of the flame starts to dance4-Open oxygen valve until feather turns into a small cone

Shutting Down

1-Righty-tighty2-Close oxygen valve first3-then close acetylene

Backfire

-Flame goes out with a loud pop -Caused by flame going out suddenly

-Causes of Backfire -Tip too dirty (Obstruction in the welding tip)

-Torch touches the work piece-Adjustment of flame is set too low or incorrect-Dirty metal-Damaged or loose tip-Tip is overheated

Flashback

-Flame burns back inside the tip, the torch and the hose

-Causes of Flashback -Backfire-Procedure to Follow -Turn off torch valves

-Clean tip