Why does my weld have blow-through / burn-through?

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Accepted Answer

Blow-through / burn-through is caused by too much current or too slow travel on thin sheet. The fix: drop amps, move faster, use skip welding, or tack tighter and stitch. Root causes. Too much current or too slow travel on thin sheet.  The fix sequence.  drop amps, move faster, use skip welding, or tack tighter and stitch Change one variable at a time and re-test on scrap Re-inspect the finished bead — chisel, brush, look When to grind it out. Structural or pressure work with visible defects: grind back to sound metal and re-weld — never 'cap over' a defect and hope. For non-critical jobs, judge honestly: a cosmetic defect is a learning note; a fusion or crack defect is a redo.

Root causes

The fix sequence

When to grind it out

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