Cheap two stage model rocket

If you were to take two model rocket motors and remove the secoundary charde from one and possibly fill the rest of the cartrage with homemade propellant. if you put one cartrage ontop the other an secured it with a little tape, would that work as a two stage rocket. does anyone think that the flame would travel into the secound cartrage and the pressure would blow out the first cartridge. Justr wondering if anyone tried this.