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"Trying to make mild steel take on a copper color with patina"
January 27, 2010
I do large scale metal etching and have a client that saw a sample piece in my studio and was sold on it on sight. The sample was an etched pattern with a bright copper/bronze appearance. The patina was wiped on cold and gave it this immediate bright copper finish, like a new penny. When coated with Permalac it maintained this finish.
The situation is, I don't know what the patina really was. It was in a bottle mislabeled as Birchwood Casey M24. It appears green in color and is translucent and not cloudy.
I have BC M24 and it does not make the mild steel appear as copper. I'm nearing my deadline for the project and am needing to either FIND this mystery patina, or disappoint a client.
I need to find it!
Any help would be useful.
Hoping to find an answer soon.
architectural metal fabricator. - Oakland, California
A mix of sodium nitrate and potassium chlorate will give you that orange color. The object to be colored should have a very high polish for best results. It will only work on common forms of steel. Stainless steel and very high carbon steel like D2 or M7 will not color. You have to wash the colored part in water and dish soap after and then fix it with oil or some sort of clear Finish or it will rust like a tin can on a tuna boat.
You could try Birchwood Casey Plum Brown. You will have to get the finish to the very highest polish you can and put it on COLD NOT HOT. Its a very weak solution so you may have to play with it. Its best to mix your own if you can. All you are making is rust its the high gloss finish that makes it orange. Salammoniac (Ammonium Chloride) may work as well but its getting hard to find now. Some of the old maw and paw hardware's still carry it as well as some of the welding shops. It sort of fell out of favor with the advent of Bondo [affil. link to info/product on Amazon] for auto body work.
Edmonton, Alberta, Canada