Hi there,

I'm having a few parts (originally bare cast steel) blastwd, to make sure rust is banished from my engine. The thing is, the steel parts will be more prone to rust when blasted than before. Sure, cast steel parts will be less likely to rust through (before that happens, the car will be long gone) but I would like to keep a clean surface. Preferable in the nice darkish grey/anthracite finish which most steel parts have when freshly cast.

What would you do? I can of course paint the parts, but paint will flake off someday...

Do we have any metal experts here? I know aluminium (or for the 'Muricans here Aluminum) can be anodized. What is possible on the steel side, apart from galvanisation?

Cheers

Damien

 

Which parts are cast steel Daim?

 

Might be forged steel but...

- tensioner arm of AC compressor
- casing of fan bearing on engine (must be cast)
- pulleys on front of engine

 

Allow a thin rust layer to form, followed by application of a solution to convert to ferric tannate, then oil. Lots of products out there.....some even work. 8-)

Some explanation here: http://canada.pch.gc.ca/eng/1439925170382

As parts are (relatively) small, you could also try one of the commercially-available "cold-bluing" solutions intended for firearms.

Or, one of the do-it-yourself-in-your-wife's-oven powder coating kits......at your own risk of ensuing marital discord.........

 

I had thought of that, but then again, I am looking for something durable and pleasing to my eyes...

After searching, what about the 'chemical blacking solution'?

 

Cast iron is one thing.


Cast steel, another.


Forged steel, yet another.


Stamped steel as well.


Some of some, here Daim.


Blackening, is known here as Parkerizing.


Add chrome or nickel plate. Might be an issue in Germany. Tis a dirty process.


I did some on a past project in gun blue. I liked it a lot.


Carl

 

CHROME !!!!!!!!!!! Actually, Birchwood-Casey, based here in Minnesota, has/had a decent cold-blacking kit available a number of years ago, which worked well. I think, on your side of the Big Pond, "Blackfast" is one of the firms that produces a do-it-yourself kit that may work for you. The firearm finishing kits are widely available here, as this society still seems to enjoy arming itself to the teeth for reasons that are somewhat mysterious. Here endeth the social commentary for the day....8-/

 

I'd like to avoid galvanizing these parts, as I need the original look. If the steel is blackend, it is still nearly the original finish vs. a plated one. As I have said often before, I need this engine to look basically as favor as it can get. Maybe even better.

 

My hobby is restoring vintage Corvettes and I have learned quite a few techniques, tricks and chemistry for recreating the original finishes on various parts as everything is judged on originality. Carl points out correctly that there are many different materials and many different types of surface finishes used by auto part manufacturers. In the case of Corvettes, the metal finishes were never intended for longevity, rather as long as it didn't start to rust before the customer drove it off the dealer's lot, then it passed GM's quality criteria. The National Corvette Restorers Society forum is an excellent source of knowledge on auto part finishes and I believe there is a limited search function allowed before you have to pay to join.

One of my favorite products is Gibbs brand penetrating oil. I use it a lot.

For a cast iron part like a differential housing, what I do is similar to the tannic acid method mentioned, but with some hardware store supplies. After blasting clean, the surface is very shiny. I mix a weak solution of muriatic acid (pool supplies) and brush it on over the entire surface, then rinse it off and dry it with a towel. The surface will rapidly turn an even shade of light orange. Then I follow that up by brushing it with Ospho (phosphoric acid rust converter). You can watch as the surface turns immediately blue-grey. Wipe it off quickly or it'll turn white tho. Then I coat it right away with Gibbs brand penetrating oil.

Pulleys that appear black but are not painted, are possibly manganese phosphate or black oxide. Phospating is done at like 180-200 degrees F, but small parts are easily done at home, even just heating up a cup of solution in the microwave. Black oxide is the easiest of all, just dip a few seconds at room temperature. But to protect it, test an inconspicuous spot before applying any kind of penetrating oil or other chemicals. I've found the solvent carriers can sometimes damage oxidized or even chromated finishes. Good ole WD-40 seems best for phosphated finishes like parkerizing.

Another treatment is called Boshield T-9 developed by Boeing and it leaves a kind of waxy film when the carrier evaporates. I like it for larger sheet metal surfaces like gas tanks.

I treat cast exhaust manifolds with dry graphite lube as it gives them the perfect fresh from the foundry appearance and holds up to the heat for at least a while.

The key with anything is periodic reapplication but in the case of classic cars that aren't driven much and never driven in the rain, these tricks work pretty good.

 

Manifold dressing, ceramic, or powdercoat would be my suggestion.

 

Seems like there is a method of making the parts stay grey but at the same time resist rusting.

 

I've got an exhaust manifold on an old Toyota that I sprayed with "Cast Blast" about 20 years ago. It held up about 6 years before it started getting little rust spots showing through. It might have held up better if I'd had a proper oven to cure it, but I just sprayed it and ran the engine. Some of these modern restoration products are great but depending on what your needs/desires are. In the Corvette world, the judges can spot painted or coated finishes from 50 feet away and we lose more points than if we'd just let it get a little surface rust. I have no idea what Jaguar judging criteria is like, whether such finishes are frowned upon or not.