To use the relay delay formula T = R R1.C1.0.85 where the unit ohm microfarad with C and T with second.If you use a bigger relay you must also use a transistor buffer is greater too.
Component List: Part Total Qty. Description Substitutions C1 1 See Notes R1 1 See Notes D1 1 1N914 Diode U1 1 4011 CMOS NAND Gate IC K1 1 6V Relay S1 1 Normally Open Push Button Switch MISC 1 Board, Wire, Socket For U1