Conversely, a catalyst solution consisting of {HEAD ~ 0.25%} by volume of catalyst engenders an approximate 15 second interval to {TAIL ~ completion} of hardening 
Conversely , a catalyst solution consisting of { HEAD ~ 0.25 % } by volume of catalyst engenders an approximate 15 second interval to { TAIL ~ completion } of hardening
OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL OTH OTH