Axis vs Allies model group hi matthew the whole point of chippin as im sure you know is to flake off the top colour to reveal a different colour underneath, as in this tank , chip off the yellow to reveal a rusty colour,paint the kit in the under colour , then give it a coat of clear matt, let this harden or cure at least 24hrs ,if you use an airbrush try find some hairspray in a pump spray bottle, unscrew and tip a bit in the colour cup, airbrush 2-3 good coats onto the kit , if you can only find an aerosol hairspray then spray it into a shot glass or egg cup till you have enough to fill the colour cup, if you dont have an airbrush use the aerosol type straight on to the kit ,let it dry then add the top colour and let that dry, then wet the kit down with warm water and use a stiff brush or toothpick start chippin and scratchin the top coat off , basically the hairspray acts as a water soluble barrier between coats , once wet it will come off with a scrub