(a)       Use sketches to differentiate the three types of welding flame.
                        (b)       State two causes of backfiring in gas welding.
                        (c)        List five welding defects.

Most of the candidates who attempted this question were able to give the required response to part (a) of the question.  The required responses to parts (b) and (c) are given below:

(b)       -           incorrect gas pressure;
            -           over heated nozzle tip;
            -           incorrect lighting up;
            -           working with a loose nozzle.
(c)        -           slag inclusion;
            -           porosity;
            -           crack;
            -           lack of penetration;
            -           undercut.