3. (a) What are the characteristics of good cast iron “filler-rods”?
(b) Can piston rings and other small scraps of cast iron be used successfully as “filler-rods”? Explain why.
4. (a) What is the purpose of a flux?
(b) Is a flux used in the welding of cast iron?
5. (a) Name one formula for making a cast-iron flux?
(b) How often is the flux applied, and by what means?
(c) In what condition are fluxes kept when not in use?
6. (a) How should the flame be held in the welding of all cast iron?
(b) When and how is the “filler-rod” added to the weld?
7. (a) Name the one principal cause of blow-holes and hard spots in the weld.