# Blackened Stainless Steel
**URL:** https://forum.4specs.com/t/blackened-stainless-steel/3581
**Category:** Archive - Specifications Discussions #6
**Created:** [June 20, 2019, 11:20pm UTC](https://forum.4specs.com/t/blackened-stainless-steel/3581 "2019-06-20T23:20:02Z")
**Posts on this page:** 10
**Page:** 1
### Author:  [@gary\_barnett](https://forum.4specs.com/u/gary_barnett)
#### Post date: [June 20, 2019, 11:20pm UTC](https://forum.4specs.com/t/blackened-stainless-steel/3581/1 "2019-06-20T23:20:02Z")
I have a client who wants to use blackened stainless steel lawn headers to separate different landscape items; for example decomposed granite from washed gravel or grass. I am concerned about the longevity of the “blackened” finish. Does anyone have any experience on the expected life of the finish in an exterior application? This project is in Northern CA.
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### Author:  [@lynn\_javoroski](https://forum.4specs.com/u/lynn_javoroski)
#### Post date: [June 20, 2019, 11:37pm UTC](https://forum.4specs.com/t/blackened-stainless-steel/3581/2 "2019-06-20T23:37:56Z")
It’s been quite a few years, so this information may not be current, and it was an interior application for blackened steel. But, all those caveats aside, the consensus among the blackened steel experts I contacted was “don’t do it”. The color can’t be guaranteed to be consistent or to last. They suggested coating the steel instead.
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### Author:  [@dbhelphrey](https://forum.4specs.com/u/dbhelphrey)
#### Post date: [June 20, 2019, 11:48pm UTC](https://forum.4specs.com/t/blackened-stainless-steel/3581/3 "2019-06-20T23:48:36Z")
I’d also be concerned about the chemicals used for the blackening leaching into the soil - no idea if they’d be harmful or not, but would definitely want to know before proceeding.
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### Author:  [@guest](https://forum.4specs.com/u/guest)
#### Post date: [June 20, 2019, 11:59pm UTC](https://forum.4specs.com/t/blackened-stainless-steel/3581/4 "2019-06-20T23:59:25Z")
A number of companies produce colored stainless steel sheet for exterior applications. Two I’ve specified products from in the past are Rigidized and Rimex. More could be found here: [http://www.4specs.com/s/05/05-7010.html](http://www.4specs.com/s/05/05-7010.html)
I don’t know how their finishes would hold up for a lawn header application though. I’m assuming surface abrasion from the decomposed granite or gravel would be an issue.
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### Author:  [@nwoods](https://forum.4specs.com/u/nwoods)
#### Post date: [June 21, 2019, 12:10am UTC](https://forum.4specs.com/t/blackened-stainless-steel/3581/5 "2019-06-21T00:10:00Z")
Could the designers be thinking of Cor-10 steel?
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### Author:  [@gretaeckhardt](https://forum.4specs.com/u/gretaeckhardt)
#### Post date: [June 21, 2019, 1:15am UTC](https://forum.4specs.com/t/blackened-stainless-steel/3581/6 "2019-06-21T01:15:31Z")
We recently had a very interesting presentation in our office from someone at Rimex, a company that produces a wide range of stainless steel surface treatments. I suggest you contact that company.
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### Author:  [@jsandoz](https://forum.4specs.com/u/jsandoz)
#### Post date: [June 21, 2019, 12:38pm UTC](https://forum.4specs.com/t/blackened-stainless-steel/3581/7 "2019-06-21T12:38:29Z")
For once I may have some useful information on a topic. Last October I had a similar request on a project. My research come up with the following:
There are basically three ways to blacken stainless steel. One involves caustic solutions such as sodium hydroxide and nitrates in a high temperature bath (~300 deg. F) which convert the surface to magnetite. This process is similar to “bluing” steel as with gun barrels.
A second is similar but the conversion method is performed at a lower temperature (220-245 deg. F) which is below the boiling point of the solution and gives off less toxic fumes.
There is a third process which is applied at room temperature. It is not an oxide conversion but is the deposition of a copper selenium-compound. Copper selenide is itself toxic [https://www.guidechem.com/msds/20405-64-5.html](https://www.guidechem.com/msds/20405-64-5.html) and must be handled carefully.
Further, and as might be expected, the more environmentally friendly the process is the less durable the finish.
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### Author:  [@lazarcitec](https://forum.4specs.com/u/lazarcitec)
#### Post date: [June 21, 2019, 3:49pm UTC](https://forum.4specs.com/t/blackened-stainless-steel/3581/8 "2019-06-21T15:49:45Z")
“For once I may have some useful information on a topic”…I disagree James, I typically read your posts each time, perhaps it is because you were a friend of the late Ralph Liebing (both a mentor and an adversary). Keep posting.
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### Author:  [@jsandoz](https://forum.4specs.com/u/jsandoz)
#### Post date: [June 24, 2019, 12:48pm UTC](https://forum.4specs.com/t/blackened-stainless-steel/3581/9 "2019-06-24T12:48:28Z")
Jerome, I hope you mean that I do occasionally have useful information to share. 🙂 Yes, Ralph was an amazing gentleman and it is to my great advantage and pleasure to have known him.
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### Author:  [@lynn\_javoroski](https://forum.4specs.com/u/lynn_javoroski)
#### Post date: [June 24, 2019, 1:02pm UTC](https://forum.4specs.com/t/blackened-stainless-steel/3581/10 "2019-06-24T13:02:12Z")
Agreed, Ralph was a good friend and it was my privilege to have also called him friend and mentor. (and, James, you DO have useful information to share - occasionally - grin)