at room temperature approximately 75 u00b0 f and naoh was added to adjust the ph of the hpg solution to a ph of approximately 11 to 12 i e 0 025 wt a waring blender set on low speed served to mix the hpg solution the hpg solution 500 ml was poured into the waring blender cup which had a total cup capacity of approximately 1 liter the blender was connected to a rheostat and the rheostat adjusted to 45 of the full scale when the hpg solution was stirred in this manner a vortex was produced in the hpg solution that extended almost to the blender blades mixing the hpg solution as described provided a moderate mixing of the hpg solution that simulated the mixing observed in field tanks the borate source was added to the vortexing solution and the gelation time measured the gelation time is the time interval from the addition of the borate until a substantially non flowing gel is produced in addition to the gelation time the time interval from the addition of the borate until the vortex began to close indicating that gelation has begun was also recorded when 0 3 gm 0 06 wt of borax was added to the vortexing hpg solution gelation occurred at room temperature in less than 30 seconds in contrast when 1 5 gm 0 3 wt of 20 40 mesh ulexite was added to an hpg solution of the same concentration the vortex began closing in approximately.