UNIT 23 REVIEW QUESTIONS ANSWER KEY GO BACK TO INDEX
23-1) Why must proper protective clothing be worn during soldering and brazing?
23-2) What harmful light is produced during soldering and brazing?
23-3) What harmful light is produced during welding?
23-4) What material should clothes worn during soldering and brazing be made of?
23-5) List the three types of torches used for soldering and brazing.
23-6) Why must an acetylene cylinder be used in the upright position?
23-7) List the common sizes of acetylene cylinders
23-8) Why should the valve on an acetylene cylinder not be opened more than 2 ½
turns?
23-9) What can happen to an air acetylene torch if it is used with too low a flame?
23-10) What is an advantage of the oxyacetylene flame compared to air acetylene?
23-11) What can happen to an oxyacetylene torch if it is used with too low a flame?
23-12) What is the difference between brazing and soldering?
23-13) What is the purpose of flux?
23-14) Why is it important to heat braze joints as quickly as possible?
23-15) Why must the copper fitting be cleaned before brazing it?
23-16) When making a brazed copper joint, what part is heated first?
23-17) Why is it important to fill the brazed copper joint completely when R410A
refrigerants are used?
23-18) Why is it important to make the braze on a compressor stub as quickly as
possible?
23-19) What alloys make up the soldering alloy often referred to as silver bearing
solder?
23-20) How does nitrogen purging prevent the formation of oxides?
23-21) What is “reverse flow” in oxyacetylene torch and how can it be dangerous?
23-22) How can reverse flow be avoided?
23-23) What PPE is required for brazing?
23-24) What is the minimum OSHA recommended shade for safety glasses used
while brazing?
23-25) List the procedure for adjusting an oxyacetylene torch for brazing.
Check to see that the regulators on the acetylene and oxygen cylinders are
adjusted out CCW.
23-26) List the procedure for lighting an oxyacetylene torch.
To prevent potentially dangerous backfires in the torch, acetylene is always
ignited first and turned off last.
23-27) Why is nitrogen brazing particularly important when working with systems
that use HFC refrigerants?
23-28) What brazing material is used for connecting copper lines to brass and steel
valves?
23-29) What brazing material is mainly used for connecting copper to copper?
23-30) What is the purpose of the phosphorous in copper phosphorous brazing rods?
23-31) How is the solder melted when soldering?