RED Matthews
Well-Known Member
Well this is confusing. They didn't and couldn't whittle in an iron mold. Early iron molds that had mold iron castings of plain cast iron, took heat out of the glass to fast and caused what should be called cold mold ripple. When they started chilling the cavity of mold castings, by pouring the molten metal against a cold iron cavity formed iron piece, it created dendritic carbon in the mold iron cavity wall, for the depth of about a half inch. This type of iron has a reduced heat extraction rate and did not cool the glass to irregular thickness. That chill had to be knocked out of the new casting immediately when the pouring is done.This glass condition could not be correctec in the bottom part of the three mold - dip mold base, so those bottles had to have the cold mold glass in the lower part of them. I covered this subject in an earlier home page wright=up.that was done before I found this marking in the three mold bottles I obtained. RED M