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