I want to prevent corosion on my new brake rotors. I have read here and seen that many new rotors from Baer etc. are Zinc washed. I called my local plater and they said that they can do zinc plating. I am assuming that zinc plating and zinc washing are the same??? Has anyone done this, and/or does anyone else have some knowledge on this subject that they could share with me.

I am just looking for some insight so that when I take the rotors in to the plater I can speak with a little bit of knowledge. Thanks.

I too would like to know more about this. I have four new rotors I'd like to keep looking good.

I am taking mine in on Monday morning, so I will report back on what I find out either way.

I don't no for sure what zinc washing is, but zinc plating is just galavanizing. If you got the rotors galvanzied they would have to be machined to remove the zinc from the surface. Also I don't know what zinc would do to the cutter blades, so some places might refuse to turn the rotors.

Just taking a guess.

Later
Steve

I don't have all my reference books handy, but the way I understand it, a zinc wash is a very thin coating (on the order of microns...like .000010 inches). Maybe they mean zinc phosphate which tends to leave a black color or zinc dichromate which leaves a yellow/gold sheen behind?

Zinc plating is going to be on the order of thousandths of an inch. (.005?) So we are talking orders of magnitude. I suppose the plating would be OK, but I don't know how your brake pads would react to a thick layer of zinc gumming up the works. It should be possible to machine the rotors after the coating, I don't think there would be any physical trouble there, but, as mentioned, some places may refuse to do it just because it's unknown. Plus now you have already machined the rotors before you ever used them. We won't even bring up hydrogen embrittlement which can lead to the brake rotor shattering. :eek:

Maybe call up baer and get some technical help about exactly what goes into the coating then confer with the plater.

Thanks Guys. I'll dig a little deeper.

I had my rotors zinc washed from SSBC. It ends up looking like I spraypainted them silver! Keeps them from rusting...except for where the brake pads run of course. The zinc was worn off of there the first time I hit the brakes! I have seens some people with rotors that looked like chrome. They said they were zinc plated. Even the contact area was polished, so I believe that you don't have to get them turned. Good luck, let us know what you find out.

I do not know what this is all about for sure, but here is my guess:

In corrosion, there is electron transfer. It is much like a chemical reaction in a battery. Zinc will give up its electrons easier than iron/steel/alum etc. You may have heard of a "sacrficial zinc anode" that is used with aluminum boat props to prevent corrosion. I am guessing the zinc wash does a similar thing: provides a 'corrosion' source that is not the base metal. Eventually the zinc would be all used up, but that would take some time.

Maybe I am out to lunch here, but it is my guess. Hope someone can clarify further.

Well here is the results:
http://www.chevelles.com/showroom/airrj/Rotor1.JPG
http://www.chevelles.com/showroom/airrj/Rotor2.JPG
http://www.chevelles.com/showroom/airrj/Rotor3.JPG

The rotors were Zinc Plated. And they were done to a thickness of about .0004". I didn't verify this but that is what I was told. We will see how they hold up.

I also had my hubs Electoless Nickel Plated at the same time. Again this was done to about .0004" thickness. I don't know how either of these finishes will hold up, but for $90 I will be my own test dummy. And I think they look cool. graemlins/thumbsup.gif graemlins/thumbsup.gif

http://www.chevelles.com/showroom/airrj/Hub1.JPG
http://www.chevelles.com/showroom/airrj/Hub2.JPG
http://www.chevelles.com/showroom/airrj/Hub3.JPG

Wow, looks good RJ!

I know you'll be fine, but let us know how the bearing race interference fit works out on the hub.

BTW, I couldn't tell that hub used to be a rotor if I didn't know otherwise. :cool:

Joe

Looks very good!

What about problems like bearings fitting into hubs? I know it's only 0.0004" but that's alot on a press fit, isn't it. I wonder how the pads are gonna take to the zinc surface.

I am so positive. :D They do look real pretty. graemlins/thumbsup.gif

Later
Steve

Steve,

I hopefully will be pressing in the new bearings tomorow and so I will report back. I don't think I should have a problem with an extra .0008" on the diameter, but if it is a problem I may chuck them up in the lathe again and give the bearing race seats a light polish with some fine emery cloth.

As for the zinc on the rotor face I have to decide on one of two options. First I have an old, but still good set of pads that I could run to wear off the zinc. Or again I could chuck the rotors up in the lathe and polish off the zinc on the braking surface.

Trust me I have been trying to think of all of the problems that I could encounter. :D

The hubs are installed now and the bearings pressed in without any major incident. I did use a little emery cloth on the bearing race seats before I pressed them. It definately aded some resistance, but it wasn't too significant.

Originally posted by airrj:
Steve,
As for the zinc on the rotor face I have to decide on one of two options. First I have an old, but still good set of pads that I could run to wear off the zinc. Or again I could chuck the rotors up in the lathe and polish off the zinc on the braking surface.
RJ,
Are you going to run the "52" series pads or the larger pads that come on police & '94-'96 Impalas? The part number is something like A-614 (I think).

Good to hear no problems with installing the races. Man, your hubs make mine look like....we'll...ugly like Cooter (http://www.chevelles.com/showroom/CooterPic.jpg)!! ;)

Joe

Joe,

I have a set of D-52 pads. If you tell me that there is a larger pad that fits the same caliper than I will have to check it out.

$90.00? I think you paid a little too much to have them plated. I have had a few things zinc plated and the place I use charges a $50.00 minumum, they acid wash the parts and they come back looking like brand new, not that your rotors don't look good. The $50.00 will do a 5 gallon bucket of parts and the price goes down from there the more you have done, I think the price for two five gallon buckets is about $80.00.

Ken,

The hubs were quite a bit more expensive than the rotors. Electroless nickel is fairly expensive. Also, I really didn't shop around to much for price. I picked the closest shop to me and paid the money. I am going to try the plating on these parts and see how I like them. But now that I have done these parts I have been temped to take a bucket of small parts to get plated also. And so you are probably right that I didn't get the 'Blue Light Special' but I'm happy. graemlins/thumbsup.gif

Originally posted by airrj:
Joe,

I have a set of D-52 pads. If you tell me that there is a larger pad that fits the same caliper than I will have to check it out. Yep, there is. I'll have to get the correct part number from my books, but they came on mid '90's Caprice cop cars and the book I have lists them for Impala SS's from '94-'96.

I do believe the pad is 30% larger (surface area). This will lower your lining pressure (the pressure the brake pad sees...its nothing major) and with your big calipers it can't hurt you to run them. That is unless they are :eek: expensive. We'll see.

Joe

When you get the small parts plated make sure you don't have anything with springs that have tension on them in there, the springs will break when they hit the acid. Zinc does not stick to stainless steel. I leave the parts dirty, the plater cleans them. The parts can have surface rust and grease on them and they come back looking like new. To get the gold color all they do is dip the parts in a dye after they are plated. I once had a Hurst shifter plated without taking it apart and it looks real good LOL.