I know Kerr is gone, but here is someone selling 25lb boxes of investment pretty damn cheap with FREE SHIPPING. https://www.ebay.com/itm/25-lbs-Sat...itm=362525185138&_trksid=p2047675.c100623.m-1
Yeah I use that stuff for jewelry casting. Easy to work with, comes off clean if you dunk it in water while still hot. Lasts years and years and years in storage. No issues.