This paper describes the application of the traditional four-point ben
ding technique to conduct strain gage performance tests at moderate te
mperatures. The tests measure the apparent strain, linearity, drift, c
reep and hysteresis behavior to ascertain the reliability of strain ga
ges to be used in the testing of experimental cylindrical vessels subj
ected to thermal loading. The four-point bending rig was designed to t
ake advantage of the advances in personal computer data-logging and gr
aphical processing software. The test rig is designed to provide a the
rmal barrier to minimize the heat losses and thermal isolation of the
test beam while maintaining structural continuity. A low wattage and l
ightweight electric foil heater incorporating a precise temperature co
ntroller minimizes weight and enhances temperature stability. Gage per
formance data on five ''candidate'' strain gages at temperatures rangi
ng from ambient to 215 degrees C (419 degrees F) are presented, and th
e evaluation procedure is outlined. The strain gage with the most acce
ptable performance was identified within the validity limits from ambi
ent to a temperature of 215 degrees C and from zero to a maximum strai
n of 1000 mu epsilon.