I am a custom knife maker and want to revisit an old technique I
used 25 yrs ago for acid etching designs on stainless blades. I no
longer have access to nitric acid, only sodium nitrate. I am
wondering if I can use a substitute for hydrochloric acid, something
cheaper than concentrate, and, if so, how I combine the sodium
nitrate with it so make the aqua regia. Thank you.