▁The ▁mod elling ▁being ▁completed , ▁called ▁lost - w ax ▁casting , ▁the ▁outer ▁covering ▁which ▁will ▁form ▁the ▁m ould ▁has ▁to ▁be ▁applied ; ▁this ▁is ▁a ▁liquid ▁formed ▁of ▁cl ay ▁and ▁pl aster ▁sufficiently ▁thin ▁to ▁find ▁its ▁way ▁into ▁every ▁detail ▁of ▁the ▁w ax ▁model . ▁Further ▁coat ings ▁of ▁liquid ▁are ▁applied , ▁so ▁that ▁there ▁is , ▁when ▁dry , ▁a ▁solid ▁outer ▁co ating ▁and ▁a ▁solid ▁inner ▁core ▁held ▁together ▁by ▁the ▁metal ▁ro ds , ▁with ▁the ▁work ▁of ▁art ▁model led ▁in ▁w ax ▁between . ▁He at ▁is ▁applied ▁and ▁the ▁w ax ▁mel ts ▁and ▁runs ▁out , ▁and ▁the ▁mol ten ▁metal ▁is ▁pou red ▁in ▁and ▁occup ies ▁every ▁detail ▁which ▁the ▁w ax ▁had ▁filled . ▁When ▁cool , ▁the ▁outer ▁cas ing ▁is ▁carefully ▁broken ▁away , ▁the ▁core ▁ra ked ▁out ▁as ▁far ▁as ▁possible , ▁the ▁project ing ▁ro ds ▁are ▁removed ▁and ▁the ▁object ▁model led ▁in ▁w ax ▁appears ▁in ▁bronze . ▁If ▁further ▁finish ▁is ▁required , ▁it ▁is ▁obtained ▁by ▁tool ing . ▁ ▁Greek ▁and ▁Roman ▁ ▁Co pper ▁came ▁into ▁use ▁in ▁the ▁A ege an ▁area ▁near ▁the ▁end ▁of ▁the ▁pred yn astic ▁age ▁of ▁Egypt ▁about ▁ 3 5 0 0 ▁BC . ▁The ▁earliest ▁known ▁implement ▁is ▁a ▁flat ▁c elt , ▁which ▁was ▁found ▁on ▁a ▁ne ol ith ic ▁house - floor ▁in ▁the ▁central ▁court ▁of ▁the ▁palace ▁of