Decorative acid-wash on plate steel

I want to acid-wash a piece of plate steel to create a decorative finish. The steel will be used as a heat shield for a wood-burning stove. We were told this was an easy process of just applying muriatic acid for a few minutes and then washing off but we cannot find anything on the web that gives us more information. Can you provide help with this?

If you mean a rusty part, just dilute pool acid by 1 part acid to 3 parts water. Add acid to water.
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Just soak it in the acid for a few minutes and rinse it off with a hose. It will rust rapidly. Deeper rust if you spritz it with a dilute salt spray every night.
When you get the level of rust that you want, bake it at 400 for a few min, allow to cool and clear coat.
Alternative 1 is to coat it with lard and bake it for an hour. This is kind of like seasoning an iron skillet.