Blacken Stainless Steel Patina Darken Metal Finishes

wrote:


And you have to watch the lacquer thinner you get these days, too. At least the body shop supply was nice enough to label their 5 gallon tins "recycled". Good enough for paint gun cleaning, I wouldn't use it for diluent. Solvent prices shot up about the time gas was going past the $5 mark on the coasts, they never came back down. Used to pay less than $5 for a gallon tin of acetone at the hardware store, same for V.M.& P. naptha, it's almost 4x that now. Some of that's inflation, but not all. They nail me $25-30/gal for urethane diluent at the body shop supply now.
I use V.M. & P. naptha for most of my pre-priming paint prep, gets the grease and dirt off and goes away. Haven't had any residue problem with it that I can see. Downside is that if you get a drop on jeans or shirt, it spreads out and gives a nasty chemical burn, but mineral spirits will do that, too. Just have to be careful.
Stan
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

Years ago I was etching some printed circuit boards using ferric chloride from Radio Hack. I had a polished stainless hemostat that I used to fish the board out. It immediately turn a dull black. I never bothered to polish them up again, and they still have a dull grey finish after a couple decades of use for other stuff.
Might be worth experimenting with.
Doug White
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

I just tried this with a what I think is 304. It did not blacken it but it etched it instead. Photo on my website
http://www.viatrack.ca/Misc/SSetch.jpg
Regards,
Boris Mohar
Got Knock? - see: Viatrack Printed Circuit Designs (among other things) http://www.viatrack.ca
void _-void-_ in the obvious place
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
On Sun, 05 May 2013 15:26:04 -0400, Boris Mohar

It's a lovely etch, even if it isn't what you were after.
He says that sanding out some of the surface chrome and nickel is the key to the darker blacks, plus a topcoat, which also darkens. This is one of the more interesting (and in-depth) vids I've seen about patinizing. He also mentioned something about the nickel and chromium migrating back to the surface after about a week. Innnnteresting. I thought maybe they came to the surface as the metal cooled during rolling, or something.
I adore the look of black chrome.
Maybe EPI's products would work better for your particular objet d'art, Boris. http://www.epi.com/c/black-oxide/stainless-steel
--
Always bear in mind that your own resolution to
succeed is more important than any one thing.
  Click to see the full signature.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
wrote:

:
d
de

fish

to

ut it

coln- Hide quoted text -

All bunk. Any sanding is removing the oxide coating all stainless has(otherwise it wouldn't BE "stainless"). If it's done wet, that allows the chemical to react with the metal under the oxide. Nothing more complicated than that. Soldering and brazing stainless has the same problem, getting rid of the oxide layer so that the filler alloy can bond. Can be done mechanically, by scratching the surface under a puddle of solder, or chemically, with some really nasty fluxes. Unless heated really hot, nickel and chrome in a stainless alloy aren't migrating ANYWHERE, particularly at room temperature. Probably what's happening is that the chemical blackening is getting oxidized over time. Doesn't say much for future coating durability.
Stan
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

Polytechforum.com is a website by engineers for engineers. It is not affiliated with any of manufacturers or vendors discussed here. All logos and trade names are the property of their respective owners.