Anodizing Stainless Steel Models

Hi all,
I think the "temper color" chart you are quoting from is for carbon steel? Temper colors will form on most stainless alloys, but at a much higher temp than for plain carbon steels. For example a brown/bronze color forms at around 450º F on carbon steel but it takes 734º F to form on stainless. Go to this link for the data on SS heat colors: https://www.bssa.org.uk/topics.php?article=140

Another thing you need to understand, the SS that Shapeways offers is actually a composite of stainless steel and bronze. This fact skews all the data on standard temper color charts. It will take some experimenting to achieve the coloration you are seeking. And you might not have as broad a color range as compared to other conventional ferrous materials. I have achieved very nice antique bronze shades on SW prints at around 650º F. Dark bronze with reddish purple highlights appear at around 700ºF. This is beyond the range of a kitchen oven but it can be done with a hand torch. You need to be careful so as to get an even heat. Do it slowly, keeping the flame from directly kissing the metal surface. Also, the surface condition of the object will effect outcomes. Better results are obtained if the parts are polished up a bit. A critical factor is that the object must be scrupulously clean and dry before starting the heat treatment. Wash parts well with a degreaser, rinse and dry. Wear rubber gloves, as even finger prints can muck up the process.
Good luck, this ain't rocket science just follow the rules and be careful. A coat of clear lacquer and/or conservators wax is a good idea as well. Have fun with it.

-G

has anyone considered titanium plating their stainless artifacts? I know there is a Japanese company that developed a way to do this, at relatively low temperatures. the patent for it reads something like this.

PURPOSE:To form a dense and uniform Ti plating film at low temp., by carrying out electroplating in a dry and oxygen-free atmosphere by using a plating bath composed of Ti
chloride, alkylpyridinium halide, and specific organic solvent and also using direct current or pulse current. CONSTITUTION:Electroplating is applied to the cathode to be treated in an
oxygen-free atmosphere of dry N2, Ar, etc., by means of direct or pulse current in 0.1-10A/dm<2> current density by using a soluble anode made of Ti and also using, as a plating
bath for Ti electroplating, a molten salt plating bath consisting of 50-80mole%, in total, of one or two kinds among Ti chlorides, such as TiCl3 and TiCl4, 20-50mole% of 1-4C
alkylpyridinium halide of alkyl proup, and <=75vol.% of organic solvent, such as toluene, xylene, and benzene. At this time, by using the plating bath of the above composition, the
dense and uniform Ti plating film can be formed by means of a plating bath with a relatively low temp. of 20-150 deg.C without causing oxidation.

I know this sounds like a complex issue, but I am betting some one is doing this already, and could probably rack up stuff when they do a batch plate of their own stuff, so they should be able to plate your stuff if you wait for that, for the cost of basically the extra paperwork, and sorting to make sure it gets shipped to you, and not with their batch to the people who paid for their items. (or get buddy buddy with some one who works there XD)

as for titanium chloride, I have ruined parts I was trying to anodize when I started by electrocuting it to long and using salt (sodium chloride) as my electrolyte. Works fine for bronze or brass color but anything more takes time and that chloride attacks the cathode and makes the tetrachloride which then passes through the water and gets deposited on the part being anodized, leaving a grey scale on the part. definitely a build up too, Since I have xylene here I may have to try plating some 316L with some titanium, tho, and if I get any decent results I will pop back on here and give details, should anyone want them.

titanium is not to expensive on ebay if you know where to look, and are just plating things with it, so if it works, it should be a good alternative for people here. heck I have tons of scrap titanium from making my goggles, heh heh, write me over at my web site if you want me to give you some scraps to experiment with, (www.borgsteamfactory.com/contact.html)

until I have some info, later. and good luck all.

ps, I found that the titanium was easy to anodize in just coke a cola (I used diet coke personally) to avoid the scale and chlorine issues, but use it straight, no dilution, unless you have been using it a while and the water has been evaporating out of it, then use distilled water to avoid getting chlorine in the mix.)

Glen, you are right for sure, Also note though for those experimenting, you can go up in heat and color change, so go slowly checking inbetween each temp change. the hotter it gets the more oxygen is being deposited on the surface, the heat will add more, but removing it if you go to far, is going to require sanding or some other abrasive process that will remove some of the stainless. so best to go slow and take your time, than to rush and have to destroy your part due to over heating it.

oh I was just remembering, I used a heat gun to heat up titanium to color it. I am betting this would be closer to the temp range that you want for stainless steel like the rings. good ones with a tiny tip for concentrating the hot air will bring the temp to and exceed 1000ºF so it should get you where you need. however you may have to experiment with how long to heat it, and maybe use a hole punch and relive some of the sides of the tip nozzels to get different temperatures for precise heating and coloring.

still working on the titanium coating for metals, but I have had some pretty good success with the formation of the TiCL³ so....

Coming from a paintball background, we anodize parts a vast array of colors, but there is one fundamental flaw in your question...You can't anodize steel, it is a process for aluminum mainly. There is sort of an ano process for steel, but only black that I know of. Also, there is no true "white" color for anodizing if you wanted that route anyway. Duracoat and powdercoat are good options (duracoat is thinner I believe).

psst... look at the dates