Fuskar alloy na aluminum yana da fim din wucin gadi oxide, wanda aka yi launin launi don samar da fim mai hade. Fim ɗin da aka haɗa ba wai kawai yana jure lalata da gogayya ba, har ma yana da takamaiman juriya na wuta, don haka an sanya shi cikin ƙofar wuta ta gami da aluminum. Ƙofar wuta tana da ƙarfin sassauƙa da ƙananan nakasa.