Arc Welding Introduction2

This is the content required for an introduction to our inert gas welding machine - reading this does NOT replace the mandatory session with a tutor! It will make it a lot quicker though ;-)

If you need this Introduction, please reach out to the following tutors: Lukas, Marcel, Johannes

Let's begin! First off, make sure you have read the machine's wiki page.

Safety

Personal protection:

Make sure you cover yourself completely, there should be no exposed skin at all!

• welding jacket
• welding gloves over the jacket
• ideally also a fireproof apron against molten metal drops and as additional radiation protection
• robust shoes against glowing hot beads: sandals or sports shoes with mesh top do not provide sufficient cover

Protect your eyes with a properly adjusted welding helmet during welding, and at least goggles when inspecting the weld or hammering & brushing off slag (it may be easiest to just wear goggles under the helmet so you can't forget them!)

Dangers	Precautions
CRITICAL HAZARD - extremely bright arc light damages eyes, risks include permanent blindness if used without appropriate protection UV radiation burns exposed skin	wear proper personal protection (see above) immediately stop if anything seems to be wrong with the welding helmet
extreme heat splattering molten metal workpiece heats up a lot welding gun, and wire also heat up	make sure there are no gaps in your personal protection, e.g. between pants and shoes or jacket and gloves wear only cotton clothing - synthetics could melt to your body do NOT touch hot stuff, even welding gloves just tolerate so much heat (don't ruin them) so use pliers to manipulate your workpieces if you have to
fire hazard Sparks can ignite combustible material workpiece can reach auto ignition temperature of its coating or residues welding gun is hot after welding and might ignite stuff	remove all easily combustible materials from your work area make sure your workpiece is clean know where the nearest fire extinguisher is located
toxic fumes (e.g. ozone, flux components, nitrous gases, heavy metal particles) galvanized steel (verzinkter Stahl) releases zinc oxide when welded which can give you "metal fume fever" [1] stainless steel releases hexavalent chromium (carcinogenic) other coatings may also release all sorts of unknown compounds when vaporized	grind away any surface coatings (e.g. galvanization, paint) before welding, they could generate harmful fumes or at least obstruct your weld take care of good ventilation - Use BOTH exhausts of the welding enclosure; but even that might not be enough for long sessions or difficult materials! Also, you should obviously avoid breathing in the fumes. "If the air in your breathing zone is not clear, or if breathing is uncomfortable, check to be sure the ventilation equipment is working and report concerns to a supervisor" [2] stop immediately if you are experiencing nausea and report the incident to a supervisor
exposed electricity (up to 60 V DC, 100+ A) still below zulässige Berührungsspannung - minor risk of shock equipment may overheat	reduce the chances of electric accidents: [3] make sure you are isolated (proper dry gloves, shoes and/or floor mat) from the workpiece, especially do not touch the electrode and the workpiece simultaneously unplug the welding machine when not in use if you use a cable drum, make sure to unwind it completely - a wound cable drum will induce current and heat up the cables, which may lead to a molten cable coat with high risk of a exposed mains wire in case of electric shock, always make sure to visit a doctor!
always turn off the inert gas after use, as leakage accurs

Suggested Reading

These websites may also be interesting:

• BGHM: Schweißen und verwandte Verfahren (DE) - detailed safety information
• BGHM: Arbeitsschutz kompakt - Lichtbogenhandschweißen (DE) - nice short safety overview, "checklist" style
• five potentioal welding safety hazards

Demonstration

The tutor will show you these steps in detail:

• check welding helmet settings
• set up your work in the welding enclosure
  • what way to enter best
  • close gaps, e.g. with spring clamps (long-term solution needed!)
  • bring a light with you, if necessary
• turn on the BOTH exhaust systems
  • The trunk only ramps up to high if you temporarily obstruct the airflow
• try striking an arc and depositing metal on a scrap piece (e.g. in the shape of your initials)
  • it's good to experience the often scary sensation of your first arc ignition with your tutor ;-)
  • once there is a steady arc, push forward and make little circles in the weld pool to "mix" the workpiece(s) with the deposited material