Building a sign for my company with the company name and logo cut out in 1/8" Cor-Ten (weathering) steel. It will be 2-sided with a layer of stainless steel in the middle with a 1 1/2" gap between each plate. Since weathering steel comes in a non rusted state, it might take a while for the sign to rust and it just won't look right until it reaches its rusted state. Any recommendations to speed up this process?