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
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