I did use 3" x 6" (.125) Hot rolled steel - you just have to clean the scale off with some elbow grease and steel wool (although I could have used muriatic acid to clean it as well ) - I cut a pattern with my scan n cut machine using 651 oracle vinyl (going to try pnp another time ) and used both the negative and positive image and used both sides just to see how it etches.
I bought the glass vase at the dollar store and used a metal cake pan for underneath. I had an aquarium pump from my pysanky eggs and just cut a piece of the tubing to use to bubble and clipped it to the edge with a plastic clip - from the dollar store . I also got a plastic pitcher to mix the water, copper sulfate and salt then put my piece in and poured the mixture in - 2L is enough to fill this vase to the top. 2L is 1 cup of copper sulphate and 1 cup of salt (I used the pickling salt - no additives ) and then filled the container up to top (2l mark) mixed and mixed till disolved.
So it was soooo green and bubbling - after 1/2 hour took out and used a soft toothbrush to brush off some of the copper build up then put back in.
once finished just brush more and clean off - the hardest was puling off the vinyl with tweezers
cant wait to try it out in my rolling mill
My notes :
Next phase is to test out using my PNP blue which is easier to use - and can do more details as well - and I want to go revisit my steel washers for pendants if you remember
I used pnp blue for the pattern but the etch was really for copper and not strong enough - this formula gives a really good etch so will try it this weekend - go here to find washers
https://deborahreadcom.blogspot.com/search?q=washers
