Examination — Welding I: Arc, Puddle & Bead

1.The job moves you up to 260 amps of stick welding — the highest current you have run. Which suggested filter shade goes in the hood?

2.Three ways to deal with welding fume. Put them in order from first choice to last resort.

1. ⋮⋮A fitted respirator on the welder ↑ ↓
2. ⋮⋮Extraction at the arc, capturing the plume at its source ↑ ↓
3. ⋮⋮General ventilation moving the whole shop's air ↑ ↓

3.An arc holds 24 volts across the gap while delivering 3,000 watts. How much current is crossing it?

4.A machine is dialed to 95 amps and the bead looks right. By the rule of thumb, which rod diameter is most likely in the stinger?

5.Mid-shift, a welder flips the switch from DCEP to DCEN and strikes again at the same amperage. What changes at the arc?

6.In a hurry, you clamp the work lead to a painted rail of the welding table instead of the plate itself. The arc runs weak, and the table's hinge throws sparks. What is happening?

7.Three rods, three jobs. Match each electrode to the work it was made for.

8.The rule of thumb, drawn. Place a starting-amperage point for each of three rods: 1/16, 1/8, and 3/16 inch — that is 63, 125, and 187 thousandths of an inch in diameter.

9.A beginner strikes a clean arc, then holds the rod perfectly still while welding. A few seconds later the arc snaps out on its own. Why?

10.Mid-bead, you notice molten slag creeping ahead of the puddle. What is the correction?

11.Four finished beads, four verdicts. Match each bead's appearance to what the welder's hand or dial was doing.

12.Your MIG arc stutters — the wire seems to arrive in pulses, and the bead shows it. Gas flow reads normal at the regulator. Where do you look first?

13.A thin, visible seam on a cabinet: appearance matters and burn-through threatens. Push or drag, and why?

14.In one sentence: why does stick welding tolerate wind and dirty steel that would ruin a MIG weld?

15.To save time, you weld straight across paint and mill scale without grinding. Which defect are you inviting?

16.To make sure it penetrates, a beginner sets the heat far above what the rod and joint call for. Which pair of defects is that setting buying?

17.Two thin sheets lie face to face, their rims flush, and the weld runs along that shared rim. Name the joint.

18.A drawing demands an effective throat of at least 7 mm from an equal-leg fillet. Using throat ≈ 0.707 × leg, what is the smallest leg size that delivers it, in millimetres?

19.A tee-joint callout on a millimetre drawing: a fillet triangle below the reference line with 6 at its left, and a second triangle above the line with 8 at its left. What is the fabricator ordering?

20.A newly welded gate frame arrives bowed. The maker tacked it square, then welded one long rail completely before starting the other. What should they have done instead?

21.Visual inspection of an otherwise clean fillet finds one hairline crack in the crater at the end of the bead. The verdict?

22.The whole trade in six moves. Put a fabrication job in working order, from drawing to verdict.

1. ⋮⋮Run the beads, reading each one as you go ↑ ↓
2. ⋮⋮Read the weld symbol and size the weld ↑ ↓
3. ⋮⋮Chip the slag, brush, and inspect visually ↑ ↓
4. ⋮⋮Set amperage and polarity for the rod ↑ ↓
5. ⋮⋮Fit up the joint, set the gap, and tack ↑ ↓
6. ⋮⋮Bend the coupon for the final verdict ↑ ↓