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Was the barrel you bought "pre mixed" somewhat red in color, and ready for use? If so then you might be mixing a lot more "catalyst" than you need with the sand. If the mix was dry than 2 quarts / 350 lbs. sounds about correct. With your test mixes 2 ozs. of oil to a cup of sand seems too high. The ratio will be about the same as the alcohol. Do you mull your Petro Bond or just riddle it to retemper ? Art