BLACKENING OF STAINLESS STEEL

I HAVE SOME PERFORATED STAINLESS STEEL GRILLS THAT I NEED TO DARKEN THEM TO LOOK PEWTER OR BLACK. I HAVE OF COURSE TRIED TO USE DIFFERENT CHEMICALS AND PATINAS AND I HAVE NOT BEING ABLE TO ACCOMPLISH THIS. THE ONLY WAY THAT I WAS ABLE TO DO IT IS TO PAINT THEM WITHA URETHANE. IS THERE A WAY THAT I CAN ACCOMPLISH THIS WITH A CHEMICAL, LIKE WIPING ON A SPECIAL PATINA PRODUCT OR CHEMICAL? PLEASE HELP. I HAVE ABOUT 160 PIECES TO DO!

A hot black oxide made for SS might work, but you will probably have to sub the job out as you can not afford even a small line for 160 parts.

Try old oil blackening process,it can be used on any metal (if it can be heated to max 400 °C temp). Instead oil you can use 20% shellac solution(furniture polish). Good luck!