3. (a) What kind of a “filler-rod” is used in welding aluminum?
(b) Is a flux used? Why?
4. (a) Is a cast or drawn “filler-rod” preferred?
(b) Name the two important metals which should be present and the percentage of each in the “filler-rod.”
5. (a) How should the flame be adjusted for aluminum welding?
(b) How is the flame held in relation to the work?
6. (a) How is the “filler-rod” added?
(b) In what respect does this differ from all other metals?
(c) Why can this be done?
7. (a) Name the principal characteristics of aluminum with regard to heat.