redyed a schwinn s seat,used to use masking tape,dye would run under the tape and not give a sharp edge,put liquid mask on the parting linelet it sit over nite,trimed around and removed the masking for the first color,sprayed color,took off mask when dye was dry,sharp line no run over,will also work in hard to mask paint areas,let dry,use an exacto knife or single edge razr blade to trim