Blackening steel ??
I want to blacken small parts (for aesthetics) approx 2 inches cubed , and only a few of them.
Can anyone advise the chemicals i need and the procedure i need to follow ?
I do not want to spend money on a kit I have seen that contains a gallon of the stuff.
Can i simply do this at home ?
Please advise procedure or link.
Cold gun bluing works well as an indoor finish.
You could look up Parkerizing, a little more involved than gun blu but more durable
A search on "Bluing" & "Parkerising" on the gunsmith section of this site will throw up a bunch of stuff
If you just want quick and dirty,
the simplest options boil down to (pardon the pun)
Rust it then boil it
Heat it red hot and quench it in oil
EncO and MSc sell kits at fairly reasonable cost...
Birchwood Casey cold gun bluing will darken the metal but will never be as black as black oxide. I've used the cold black oxide kits commercially available with a slightly better results than the Kmart gun blue. Worked in a pinch when a customer did not want to pay the 100.00 min. for oxide. Clean the surface very well with a degreaser and rub on the bluing with steel wool while wearing rubber gloves to prevent the oil in your skin from contaminating the surface.
- Clean them thouroghly.
- Wipe a thin layer of thin oil over them.
- Stick them in the Wife's kitchen oven as hot as it'll go for 1/2-3/4 of an hour.
- apologise to wife
Works for stuff I've blued
Blacksmiths use linseed oil applied with a rag to hot steel to get a black finish. The steel part should be hot enough that the oil smokes when applied. It will have a hand wrought look to it though but is quite durable.
I have had pretty good success with Brownells Oxpho Blue applied to clean and warmed steel.
I knew a guy who could make a steel part black as night with chemicals. He did tell me his process but I have forgotten all of it except for that he used baking soda as a rinse to prevent the stuff from continuing to rust.
While I have never used it, quite a few people in these forums seem to have had good luck using Caswell Plating's black oxide kit:
Caswell Inc. - Black Oxide Kit
For example, see this page in the PM South Bend forum. The reference to Caswell and some pictures are about halfway down the page:
1947 Model 9A
If you search "cold black" and "cold black oxide" on these forums you'll hit more posts on these cold black kits.
I've tried a bunch of the kits and never had any reasonable success, especially with cold rolled or any alloy steel. The best I could get was "cold grey", kind of the appearance of welded steel.
With the last kit I thought I really had it, after hanging the part (1018 steel) in the solution for the specified 5 minutes after I pulled it out it had a beautiful dark black and slightly velvety appearance. O boy, I had finally found cold black process heaven!
But the next specified step was to rinse the part under running water and when I did that the beautiful velvety dark black coating all went down the drain, leaving a "cold grey" part behind.
I'll double PaulT's lack of success with at least the Caswell kit. I followed the directions to the letter; the black was very a very nice luster, though still obviously different in tone from a hot black-oxide finish. Even with the "sealer", though, I have had much issue with the black marking up my hands when handling... even close to a year after coating. For parts that need to be handled, it was a clear mess. I've given up trying. Perhaps other kits are better in this respect, but that was my experience with the Caswell one.
Home made salts to blacken steel, recipe can be found here Blindhogg custom gunworks
I have not tried this myself yet but have read numerous accounts of others who have had good results with it.
Soak in peroxide, salt, and vinegar, until rusted, drop in boiling water, let dry and spray with "Extend" or other rust converter (auto section of Mega-low-mart, right by the bondo).
A cold process imported from Great Brittain is called Blackfast and a hot process (which produces a superior finish) is called Colorsal local distributor is Fuchs Lubrication oils.
The trouble with experimentation is the heating, multiple containers and minimum quantitiies required and the cost involved.
Good luck. See if you can find a gunsmith who no longer does his own blueing and might be willing to sell you his setup.