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Welding 101

Introduction:

Names, projects

Safety:
  • General safety
    • Fire extinguishers: locations
    • First aid kit located at front desk
    • The major welding hazards you will face are:
      • Sparks
      • Heat and flame
      • Arc Flash
      • Electric Shock
      • Welding Gases
      • Fumes
    • The biggest dangers come from our complacency and not being totally aware of what we are doing. Don't take short cuts that compromise safety.

  • Clothing
    • Wear long sleeves and pants without cuffs and have your pant legs cover your shoes so sparks can't drop into your footwear Wear leather boots, CSA approved boots are best, no sandals or open foot wear (green shield) 
    • Avoid wearing jewelry 
    • Wear leather gloves (demonstrate different types of gloves)
    • Wear natural fibres wool or cotton 
      • synthetic materials will melt onto your skin
  • Metal safety:
    • Hold it like it's glass (sharp edges)
    • May be very hot, always check before you grab; or wear gloves
  • Electricity:
    • NEVER touch ground & tip at the same time
    • MIG = cable is hooked up to (+) port on box
    • Don't set handle on table - hang from cart
    • "DCEP" = Direct Current Electrode Positive (electrode = welding gun)
    • We keep ground up at front desk
    • Electric shock can occur when arc welding. This usually happens when the current passes from the electrode through the welder to the piece being welded and through contact with poorly maintained electrical cables.
    • Primary electric shock is much more hazardous because the voltage is much higher than the secondary or welding voltage.
    • AC is 2 to 3 times more dangerous than DC welding.
    • Inspect your equipment to make sure it has been properly maintained.
    • Wear proper PPE to insulate yourself from electrical hazards, dry gloves and rubber soled boots.
    • Don't weld in damp conditions.
  • Gas:
    • Never move without cap!
  • Fire Hazards:
    • No flammable items/substances in a welding area (ex/ no wood dust or stains, etc.  Wood welding jigs ok.)
  • UV light:
    • Don't wear white (reflects under mask = neck burn)
    • cover all skin (to prevent sunburns)
    • always use red UV shield to protect others
    • warn others before you start: ex/ "Arc up!"
    • Masks:
      • Auto-tint = when it sparks, vision darkens
      • blocks UV light
      • "DIN" = can adjust auto-tint setting
      • 9 = brightest
      • 6 = plasma cutting
      • How to adjust knobs to head
  • Air extraction:
    • can wear a mask, but welding mask may not fit over it
    • open door, turn on overhead extraction
    • aluminum is worst, steel not as bad
    • rust & paint on metal pose dangers as fumes
      • wear a mask if you grind off (dust)
    • Welding Fumes
      • When welding the melting metal oxidizes and produce gases such as carbon monoxide, carbon dioxide, oxides of nitrogen and ozone. We also use gases such as argon and carbon dioxide in the welding process to shield the weld and prevent oxidization.
      • Metals contain many alloys that can release contaminants into the atmosphere during the welding process.
      • A coating on metal which could emit harmful contaminants (such as lead, chromium, organic materials, or toxic combustion products) must be removed from the base metal, whenever practicable, before welding or cutting begins.
    • Confined Spaces
      • Always test for oxygen levels before entering a confined space. Any reading lower than 19.5% (at sea level is said to be deficient. Use fans to ventilate the space or use a welding helmet with an air line bringing in an outside source of fresh air. If you see someone unconscious in a confined space DO NOT ENTER the space unless you a wearing a self contained breathing apparatus. In January 2003 four workers at Westminster Marine Services died. Three of them were would be rescuers.
      • Inert gases like argon are heavy and will displace oxygen in a confined space.

How to use:
  • MIG vs TIG (define, what they're used for, etc)
  • Tank: 
    • don't open too fast; 
    • watch gauges: flow (cfm) & pressure (psi) 
      • 35 CFM
  • Machine:
    • Switch on back
    • Select settings:
      • Dial @ top
      • guide inside box door - shows settings for different types of materials
    • then use +/- to select material thickness
    • spool inside machine (for steel/MIG)
    • we have a handheld spool gun for alum.
    • black knob = pressure; too much friction, wire won't push through
    • pinch with fingers, guide roller under black knob should spin and spool still moves
  • Gun itself: 
    • Nozzle comes off, spatter can be inside (which affects shielding gas) - can clean with MIG pliers
    • Contact tip (inside) - specific to wire size: 030 & 035 = standard wire sizes
  • Cable:
    • both gun & gas run through
    • if it loops, do not pull on them - will kink wire
    • expensive to replace
    • treat carefully - don't step on it
  • Table setup:
    • use magnetic squares to get 90-deg welds, etc
  • Welding technique:
    • cleaner metal = better weld
      • grinding taught in metal 101
      • no sheet metal on bench grinder
      • wire wheel/flap disc/grinding discs - clamp down!
    • MIG = adding material, needs somewhere to go
      • grind 45-deg corner on each piece to make a valley
    • start with wire out about 1/2"
    • hold gun at 45-deg to the weld
    • "tack weld" first
      • on both sides
      • so weld doesn't pull over
      • add one bead where you plan to end actual weld as well - cleaner ending
    • then "stitch" back and forth between surfaces as you push/pull the puddle
    • keep puddle the same size and moving
      • too slow = puddle may melt thru
      • too fast = only sits on top, like hot glue
      • want a consistent sizzling bacon sound - no popping or sputtering
    • wire speed
      • this machine keeps it ok
      • assumes 2 metals are the same
      • whereas if two different gauge metals, wire could need adjusting
    • close tank
    • press trigger so gauges go back to zero
    • turn flow handle so it's loose again (spins)
    • turn off machine (switch at back of box)


Things to never do

Subpages (1): Welding Manuals
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