Welding I: Arc, Puddle & Bead

The arc's light is intense enough to injure eyes and skin in seconds, so a shade lens, safety glasses, gloves, and flame-resistant cover are the first step of every weld.

Welding makes metal-oxide fume that must stay out of your breathing zone, and sparks that can smolder for hours — so ventilation, a cleared area, and a fire watch are part of the procedure.

A welding arc is a sustained electrical discharge whose plasma, near 6,000 °C, melts base metal and filler into one shared puddle that freezes into a single continuous piece.

Amperage sets how much heat the arc delivers; polarity sets where that heat concentrates — electrode or workpiece.

Welding current travels a complete loop — machine, electrode lead, arc, workpiece, work clamp, and back — and setup is the sequence that closes that loop on purpose.

A stick electrode is a steel core wire inside a flux coating whose burn shields the weld — and its AWS number states its strength, positions, and coating in a code you can read.

An arc starts from a moving touch — scratch or tap — and lives at a gap about one rod diameter wide; hold the touch and the rod sticks, lift too far and the arc goes out.

A sound stringer bead is four variables held at once — work angle, travel angle, arc length, travel speed — and its width and ripples report exactly how well you held them.

A MIG machine holds voltage constant and feeds wire at a set speed, so the arc corrects its own length — setup means matching wire, tension, and gas to that division of labor.

Travel angle aims the arc's heat and force at the puddle or at bare plate: drag digs deep and narrow, push spreads wide and shallow.

A finished bead records its own history — porosity, undercut, and lack of fusion each point to the specific thing that failed.

Every welded assembly reduces to five joint geometries, defined by how the two pieces meet — before any weld is placed.

Every weld you will make is one of two types: a fillet laid into a corner, or a groove filling a prepared opening between edges.

An AWS weld symbol compresses a joint's full instructions — weld type, size, side, and site — onto one reference line with an arrow.

Weld metal shrinks as it cools and pulls the assembly with it, so distortion is controlled before the first full bead — by fit-up, tack sequence, restraint, and weld order.

One piece of steel — fitted, tacked, and welded, then judged the way an inspector judges it: visual criteria first, a bend test after, and any failure read as information.