Rustless brake rotors

[lightning_8669]

Sorry guys for being away so long, been busy.

Anyway, a while back I posted some information on atmospheric nitro carburizing of brake rotors. The process basically involves putting the rotors in a furnace who's atmosphere is spiced with carbon and nitrogen and heating to about 1100F. Once this step is complete they are quenched in a molten salt bath at around 750F. The first step hardens a thin layer on the surface of the part to about 52-55Rc. The second step turns the parts a matte black and imparts a corrosion resistance of 200+ hours in a salt spray environment.

I have a company that will run a set free of charge on a sample basis if anyone out there would like to preserve their rotors in this fashion. The rotors will, for all practical purposes, no longer wear. Therefore, anyone wishing to try this process needs to have rust free dressed rotors for this application to meet maximum benefit. The company doing this process will be completing testing on aircraft rotors later this week. Previously aircraft rotors have been clear zinc plated.

After the initial sample set the price would come out to something like $100-$125 for between 10-12 rotors. So if there are 3 people out there wanting to treat all 4 corners of the car expect the process to cost between $35-$45 for 4 rotors.

Anyone interested either respond here or drop me an email.

[oneothefewproud]

Sounds good but does it stop them from warping? Mine are slightly warped but are smooth as glass still. If it does then I might be inclined to purchase new rotors and have it done to prevent the warping.

Thanx
Wayne

[lightning_8669]

The answer to that is a definite "maybe". There are several reasons for a rotor to warp. One reason is incorrect torqueing. No heat treat or plating process can help there. High heat is the most common cause. The front rotors on early SVXs and all four rotors on later models are vented to help dissipate heat. As the cast iron corrodes the air passages (vents) become partially blocked by rust. This layer of rust also prevents air from reaching the rotor's surface and in extreme cases it reduces the amount of material available to absorb and dissipate heat.

If you have driving habits that require you to brake from high speeds (100+) to low speeds in a short span of distance, you will have a struggle finding rotors that remain flat. The treated rotors can be (not as easily as untreated rotors) turned if they warp but any area cut will now be prone to corrosion.:( However, they can be retreated:)

I'm looking at this process mainly for its corrosion resistant properties. I've heard of people on this boad who have had rotors zinc plated but zinc only provides about 72 hours of salt spray resistance where this process provides over 200 hours. The salt spray test is a pretty nasty environment so the 200 hours is pretty impressive.

I hope this helps. Please let me know if you have any other questions. Also, if you have an old set of rotors that you'd like to try, without risking the cost of a new set, I know a local processor who can remove the rust from them. You'd want to have them turned first, however.

[1994SubaruSVX]

i may take you up on this offer. my rotors are currently zinc plated but they do occasionally have rust on them after a hard rain.

[lightning_8669]

You would either have to remove the zinc first (can be done chemically by a zinc plater) or start with raw rotors. The zinc would prevent the nitrogen and carbon from being absorbed by the cast iron.

[1994SubaruSVX]

i was talking about when i have to replace my cross-drilled zinc plated rotors. would this process work with art rotor or would that be overkill?

[lightning_8669]

What's the composition of "art rotor"?

To be honest, I have rotors on all four corners from Auto Zone (I could hear a couple of board members flinch right there). About $65 a piece. Have had a couple of "panic" stops with them and no problems to date. The panic situations were from around 85 to 30mph but was pretty abrupt.