I just totally suspend the blade vertically on a 1/16"stainless wire for the whole time. It will etch better 70 degrees and above. It doesn't like cold.
Another thing this is for carbon damascus. I use muriatic acid for stainless damascus etch for 15 minutes then follow with a 5 minute soak in ferric.
If you have the ferric when you mix it I leave it in another building to etch. Ferric vapors will rust machinery in your shop.
