I have around 340 students and I typically order about 8 boxes of the utility
buff clay- comes in a box, 2 25 lb blocks. I usually have an average of about
2 boxes left over- but because my clay projects change from year to year, I
would prefer to have a slight overage.So i guess if you wanted to do it "to
the wore" I would say, 300 lbs would get you thru about 300 students- but
keep in mind, that is for only one clay project per kid. Your hs kids will be
using it for an entire quarter- so again, I would err on more than less for
your order. Sorry I could not be of more help.
Christine in Binghamton