(b) What action will this have on the weld?
10. (a) Explain briefly how apparatus is shut-off, when not to be used for several hours or more.
(b) Why should particular care be taken to see that acetylene cylinders are tightly closed when empty?
(c) What action does oxygen have on oils and greases?
LECTURE NUMBER THREE
Subject—Welding of Cast Iron
(Part One)
1. (a) How is it possible to distinguish cast iron from such metals as malleable iron?
(b) From semi-cast iron?
(c) From cast steel?
2. (a) What kind metal is used in making “filler-rod” used in the welding of cast iron?
(b) What general rule can be laid down as to the relation of the metal in the “filler-rod” to the metal to be welded?