Metal Blackening/Black Oxide Finish

[Guest TomB]

Anyone have suggestions for restoring black oxide finish? I'm aware that Eastwood offers a metal blackening kit. Anyone have any experience with either the Eastwood kit or other blackening/black oxide methods or kits?

Thanks,

TomB

[Gary_Ash]

I used the Eastwood blackening solution. It did make the hardware black, and I finished with the clear overcoat and a bake in an old toaster oven. I may not have done it correctly, but I found that the nuts, bolts, and washers I treated rusted in a short time. I may have overbaked the sealant. Caswell Plating has a small gel kit for $20 that you can use to try it.

[Stude Light]

TomB,

I've used the Eastwood blackening solution also. Black oxide is nothing more than an oxidation process similar to gun bluing or just plain rusting. The hot oxidation processes provide a limited amount of rust protection, but the cold process (like the Eastwood) has no protective properties. Both the hot and cold processes rely on a protective coating and oil is typically used. The oxidizing changes the surface properties of the metal and allows for the oil to be trapped in the "pores". Eastwood used to offer an oil based product but now just offers a clearcoat paint for protection.

The other process that works better is phosphating (metal conditioning) which leaves a light gray finish. This process leaves crystallized salts on the surface of the metal. It has slightly better corrosion resistance but, like the oxidizing processes, leaves a porous surfaces that requires a protective coating of paint or oil.

What I have been using on my car is the Eastwood blackening process immediately followed by coating with Boeshield T-9. Boeshield is a great protective product that Boeing developed for use on their aircraft to protect hard to access parts. It is a mixture of oils and waxes that dries to a slight waxy finish. I use it for my tools and equipment in unheated garages/barns to prevent them from rusting. I have had excellent success using this process on my fasteners but it does require some periodic recoating depending on the environment. I like using it underhood, but wouldn't recommend it on an exposed surface. Paint is best for that.

Scott

[drdon]

Maybe you should look up "Parkerizing" or "Manganese Parkerizing" (black rather than grey.)

I have many parkerized parts on my '28 Harley, and I keep them lightly oiled. It

never sees weather moisture anymore unless it rains at a car show, but just in case.

Parkerizing is a gunsmithing term. You can Parkerize yourself, but fumes are nasty.

I know there used to be firms that would do it for you- but try Google first, and also check on availability of commercial firms?

My home Parkerizing came out fine and years later looks great. Good luck.

[Stude Light]

Yes, parkerizing is also a phosphating process. I was thinking of the simple cold phosphating process (gray), but using the higher temperature processes can get you dark gray, gray-green and black. All these finishes require an oil to prevent rusting. If you use degreasers when washing down your car's engine, you end up removing the oils and have to do some recoating. The Boeshield product resists washing a little better than oils due to the waxes but I still like to re-coat to be on the safe side. I agree with Don - keeping non-painted parts out of the rain is the only way to keep them looking good.

Scott

[Guest Mochet]

I use a satin clear coat after the blackening solution. The results looks good. Caswell sells several blackening solutions, including one for zinc-plated hardware. I tried it on some plated springs, and the result was very nice... and no need to remove the plating.

Phil