Blackening for steel work

[stretch]

I am looking for blackening liquids for my metalwork. I know of birchwood casey and contacted them, I am wondering if there are any others.

[HWooldridge]

Birchwood Casey makes most of the hot and cold black agents for other retail distributors - like Brownell's. I use Oxpho and it works quite well.

You can also brown it (rust) to the point of almost being black with brine, hydrogen and peroxide. Search the archives on this site - I asked for recipes about a year ago and the simplest one worked the best.

[james gonzalez]

you could try sculpt nouveau in california.
I know they carry birchwoodcasey and they may know of other options.

[Ice Czar]

hydrogen peroxide treatments work best with the steel at a pretty high heat not forge heat mind you but still a black heat, where you can see the water vapor on the steel driven off, we use a propane weed burner.

the easiest cheapest route is stove polish but it may not be at all what you have in mind

it sort of depends on what you mean by blackening and what you mean by steel. A chemical cold blue like what Birchwoodcasey offers is very different than both the above. We buy various Birchwoodcasey bluing solutions and make our own as well (nitric acid, cupric sulfate, selenious acid)

When it comes to "true" bluing (which is often black or dark charcoal) its often a heat treatment with carbon or chemicals, as applied in gunsmithing the processes have changed over time with the carbon content of the steel employed in making the parts, it gets really interesting when you look at some guns that may have up to three different bluing processes employed.

some basics
Bluing (steel - Wikipedia))
Passivation
Nitridization
Carburization
Case Hardening
Restoration Articles - All About Bluing (ARTBLUE.HTML) (good basics of the various processes employed at one point or another)

the bluing most suitable to mild steel, is slow rust bluing, which is highly labor intensive in that you card off all the red iron oxide which is a larger molecule and leave only the black iron oxide which is smaller with a tighter molecular bond, then repeat the process till you get an acceptable finish (which is covered as "RUST BLUING" by Bill Adair in the article above)

there is a great amount of confusion in bluing terminology, with many names describing the same or nearly the same processes, in British parlance substitute "blackening" for "bluing" the actual finish you get depends on the process and the steel that is employed, from a deep black to a temper blue

[Phil Dwyer]

Here are the corrected amounts for Dave Vogel's museum wax (interior) finish.

• 1.5 Cups melted beeswax (a little more than 2 cakes like at Ace Hardware)
• 1 Cup turpentine
• 1 Cup linseed oil
• 1 Teaspoon Japanese drier

He suggests combining all liquids then heat them up enough to melt in the wax (no open flames!). But, I melt the wax first and then add the other ingredients. I got all the stuff, including quart paint can and lid for storage of finished product, at Home Depot. Well actually I had the beeswax already.

Apply to 200-300 degree hot metal with a cotton applicator (we roll up old pant legs). It will smoke a bit as it soaks in. Fully cures in a day.

[Bart Trickel]

I use a product from Caswell called Black Oxide.
Caswell Inc. - Black Oxide Kit
It works good and fast, low toxicity I think also.
A bit expensive but a little goes a long way.

[steponmebbbboom]

perhaps i am being naive.

But for blackening forged steel all i do is heat the steel until it is too hot to touch, not glowing, just before colours start to run. then i wipe it down with a rag soaked in vegetable oil. just regular vegetable oil. this instantly turns the steel black.

its not like paint but it holds up ok outside.

[tzonoqua]

no you aren't being naive...

you can use vegetable oil

I use a mixture of meths or turpentine, tannic acid and a drop of oil. apply with brush when hot. gives a matt rich black/brown finish. Or sometimes I use just oil, or another favourite is 'jacobean' briwax. Only suitable for indoor uses. After a while outdoors it will eventually rust.

For outdoors I use paint, generally. Or if it's something like a big gate or railing that someone has spent a lot of money on, I send it away to be galvinized then powder coated.

Colleen

[ThomasPowers]

Boil it in strong tea ---tannic acid will blacken the surface; but you will still need to protect that from rusting.

[Dave Leppo]

I hit the steel with a wire wheel on the angle grinder when it's red hot - knocks of any scale instantly, smoothes the surface beautifully, and because the metal is hot, it immediately returns to a shiny black. This works with a hand wire brush and elbow grease, too. Then just wax or linseed oil, or the clear coat of your choice, to prevent rust
It's not really suitable for hard-to-reach surfaces, though, but this adds contrast and depth to the work, high surfaces shiny and black, low spots dark grey matt.

Obviously, this doesn’t work with anything that is heat-treated and then polished. Also, when you work the wire wheel over hot steel, it’s really aggressive, and you have to be careful. You quickly loose hard edges, and even smear your touch mark!

[Dave Leppo]

OK, sorry, reviewing the question: this is not a liquid!

[Ice Czar]

I hit the steel with a wire wheel

think you might want to be more specific

we use a brass wire wheel on hot steel to get a gold finish, and I havent noticed a black finish employing a stainless steel wheel (but then the stock wasnt at that high a temperature either)

[Dave Leppo]

Ice Czar

Sorry:

This is using a steel wire cup on the small angle grinder, with the stock clamped in a vice. At high temperature, the stock is agressively burnished by the wire brush, actually moving metal on the surface. Hence the "smeared" touchmark.

[Don A]

I just finished a set of curtain rods and hold-backs for our house.

Based loosely on someone's recipe from some time back, I took a clean gallon paint can, put four wax toilet seal rings (new ones), a big shot of linseed, and an equal (more or less) shot of turpentine.

Brushed on at black heat and rubbed-down when cool, this stuff really looks good. All of it is for the indoors, mind you.

One note of caution: this concoction has a really low flash-point, meaning that if your iron is too hot, it will burst into flame. You might need to test it, but it is very apparent when the piece is too hot. You just want it hot enough for the wax to flow good.

BTW, you will have to warm the whole can each time you use it. The wax goes back to solid when it cools. It smells good, too.

Don

[Golden_eagle]

I paint it with peanut oil and pass through the forge

[MooseRidge]

Something I learned at a JCCFS class....

Make an all metal tool handle similar to one used for a hot cut for a treadle hammer.
Thread some clean cotton strips through the eye until the eye is fully wrapped.
Dip the cotton into the heated wax/linseed/turpentine mixture until a large egg covers the end of the tool.
Let both cool then keep them covered to prevent dust contamination. (They had an old ammo can 3/4 full, kept the tool inside as well).

This way, your finish material is in a usable/mobile form, enough for a number of applications as well as minimizing the flash fire problem with the liquid "fuel" in the can....

Important Safety reminder: ALWAYS reheat the mixture in another pot (i.e. double-boiler) with plenty of water.... NEVER apply direct heat (saw a guy try to melt a puddle in a can of this stuff with a O/A torch - lost his mustache, eyebrows, and most of his hair! Though beating him about the head and shoulders WAS fun, he was very lucky no permanent damage!)

[High Plains Forge]

I use stove polish, but now I'm going to have to try the toilet wax seal recipe. That's just great!

[cwilliams]

WHen I want a nice black finish I usually heat up to just above black heat and put in a 5 gallon bucket of used motor oil, I usually keep in for about 10 or 20 seconds and if you time it right the excess heat in the piece will burn off the excess oil as you remove your work from the bucket. I get a super nice black that many ask how I did it when I do this to my art pieces, I have also rusted pieces and boiled in water to turn the rust oxide black and that looks good too but the first way is the easiest.
Chris

[Mage]

Ditto on the Used motor oil
Works great and last for years if you get is deep penetration into the surface... but the process is sinky and smoky.

Heat no... warm the piece or section if its large and either dip, pour or use a old rag to wipe on the oil.

Watch yur heat.. the oil should smoke and bubble but not burst into flame... of course be ready for it to do so at any time... but that just adds to the fun of it LOL

If an area.. like on sheet metal, is not even, reheat that area and a lil larger re apply oil.... this heat will may be enough to spread the existing oil better. If not be ready to add a lil oil to feather out to the surrounding area.

[Bentiron1946]

I use linseed oil and a nice smoky coal fire. The combination of burned linseed oil and coal smoke makes a very nice shiny black finish that seems to work OK inside/outside. I guess all of that coal tar helps with the blacking process. This is not suitable for food use items because of the coal tar.:D

[John Martin]

I have used-
-Wire Brush, then reheat to just hot, no color, apply a candle, and if it catches fire wait a little bit, if it just smokes then i run the candle up and down the metal, once cooled, wirebrush again. This one works best for me.

-Wire brush, then heat to warm to the touch, vegetable oil.

[Hofi]

Cut ONION in two halfs heat the steel not too much with a rose bud smear thw onion on the steel and u get it black. put whatever transperent finish and u get a very good
black finish result
hofi

[Chrispy]

Parkerising is a good method. Manganese dioxide and phospheric acid and some iron filings for good measure (not sure of the quantities but you will find it on the net). Mix the ingredients and heat to 53 degrees (a bit hotter than luke warm) and insert your (oil and grease free) piece of metal for about 45 minutes. Best to use a glass container - not your wifes saucepans. Easily done on the kitchen stove but be ultra careful as acid is not your best friend. It needs to be rinsed off and dried immediately after removing from the hot solution.
I made a mild steel tank 3m long x 1.5m high x 200mm wide (1500 litre capacity)to Parkerise some wrought iron gates I made a few years back. They turned out great. The parkerising makes a film microns thin that act like a sponge that sucks in whatever you choose to protect it with. Paint, resin, or oil.
Parkerising is a finish ofter used for hand guns, tools, engine parts etc. It has an extremely hard wearing surface particularly if oiled afterwards. 15 years of constant use and cleaning as with hand guns is not unreasonable. Ingredients are available at your local chemical store. Permits not required to purchase these chemicals.
Chrispy

[MVisser]

Hello, all on this site,
I am a new member, and can't find the spellcheck yet, so I'll say; sorry in advance.

I am going to take a stab at this topic of blackening steel. I have, as a machinist, needed to blacken items from time to time. The way all the shops I've been in do it is; send it out!

However, if one is in a hurry, or had to make up that missing piece of an order, back from the finisher's, we would use Birchwood Casey method, looks fine after a good rinse, dry, rub in some oil, of some sort, mineral, or non detergent -30-/wt., or boiled linseed. This has been quite passable, but to match the work done by a finisher, or ones' work from a different batch of chemicals, if the match is for a critical customer, it may take some re-work. As some of the other posters mentioned this will not stop rust for all time, even indoors, in the summer so, if sweaty hands are in contact with parts, it WILL rust. Some folks are more able to cause rust than others, in any season, I am very rusty! Having said this, there are several ways to seal the surface of the steel.

The clear spray (plastic paint/varnish, powdercoat) or boiled linseed oil, makes a skin that is remarkably durable, even outside (may be not at the shore) this will need to be reapplied periodically. Now, for the fun part, I was at a place that was making ingots of PLATINUM as an intermediate step of their process, to keep the non-hardened mild steel molds from "wetting" with the precious metal, they took rolls of card stock dipped in sugar and veg, oil and rubbed the steel as it was being heated enough to make liberal smoke.

This made a wonderful deep black that probably has good durability. If, and I can't wait to test it, one would treat a piece this way, let it cool, and rub in on a dried item some boiled linseed oil, I'll bet you that this is the ticket for general duty work. The Birchwood Casey has, even after dry, and washed with soap a toxic smell, this will not fill a room with same odor, but may not be ok. for food or children if contact would be occuring, repeatedly.

Cordially, Michael Visser

[thecelticforge]

I used to treat my traps by soaking them for two days is an emulsion of walnut husks, then dipping them in beeswax and boiling water.