N E 1 ever heard of cad plating rotors?
 

I was getting ready to buy some new rotors & they asked if I wanted them cad plated for $12 ea.
Sorry if it's a stupid question, I've just never heard of it.

Not at all a stupid question- kinda a stupid thing to pay for. Some rotors are plated with zinc and/or cadmium for rust resistance, but the plating wears off quickly from the braking surface.

The insides of my winter driven 944 rotors gets pretty rusty. It might help in that situation.
-Chris

Although I've not heard of cad plating rotors, I assume it is to protect the non-friction areas. They rust fast when unprotected.

It's common to cad plate high performance rotors. Look here for an example:

http://www.drivewerks.com/catalog/performance/Go_Brembo.htm

It does protect the non-contact surfaces from rust...

-Wayne

Yes, they do rust fast. they should be coated. Clear coat is commonly used. Cadmium would be an AWESOME coating. I'd say "yes" to that offer instantly.

I would only buy cad plated rotors for a street car

I might have to second Bill's opinion. My plater advised me that zinc or cad plating creates a hydrogen embrittlement situation and parts so plated should be stress-relieved. Are these rotors heat treated after plating?

If everything is okay, I'd say go ahead. It should keep the rust at bay for awhile.

Sherwood Lee
http://members.rennlist.org/911pcars

Besides the issue of hydrogen embrittlement ... there is the issue of poisonous dust formed when the cadmium rubs off and mixes with brake pad dust. Cadmium is very toxic when breathed!

Wayne are you sure the brembo photo-op rotors are cad plated? or are they treated with something else?

And for the hydrogen worries hydrogen embrittlement occurs during high temp coating apps... ie galvinizing. I was under the impression cad plating was aroom temp anodic or cathodic metal transfer processes

One reason I went with OE rotors instead of OEM was that I heard that the OE rotors have better corrosion protection.

Some of the Brembo rotors are cad plated, the issue for a race car is more of bite than embrittlement though that is a concern. Competition pads are designed to work w/ iron surfaces. The cad plating while desireable in a street application for cosmetic reasons greatly reduces the C_f of the pads, in addition the embrittement promotes cracking.

Duh.... I had not even thought of the non brake-surface part. How about frozen rotors?

In England Cadmium plating seems to be illegal. The golden colour plating is passivated zinc

The ones supplied by Porsche oem are zinc coated on the non wearing surfaces.

Frozen are not worth anything(IMHO)

Just spoke to Doug a VCI who stated the same thing. He has tested these compared to regular and has no difference.

The zinc coated ones will retain their appearance the non will rust unless treated. I painted mine(in this case Zimmerman) w/ a Wurth product that was handy.

http://www.owners-gallery.com/upload...odsmall100.jpg

I second Bill's opinion.

Cadmium is poisonous, i wouldn't like to have Cad dust anywhere near me. If it also speeds up cracking (i didn't know that) that's a no brainer.

Go for pure Fe and give tose 12$ to Greenpeace.

FROM AN ELECTROPLATERS POINT OF VIEW HYDROGEN EMBRITTLEMENT HAS TO DO WITH THE SCALE ON THE BASE METAL FROM THE HEAT TREATING PROCESS. IF THE ROTORS ARE NOT HEAT TREATED THEN HYDROGEN EMBRITTLEMENT SHOULD NOT BE A PROBLEM WHEN THEY ARE CAD PLATED. CAD PLATING IS A VERY EXCELLENT CORROSION RESISTENT PROPERTIES AND IS PLATED CATHODIC WHICH MEANS THAT THE CAD DEPOSIT IS NOT UNIFORM. IAM NOT SURE ON ITS ABILITY TO PLATE INSIDE THE ROTORS. I MIGHT TRY SOME ELECTROLESS NICKEL ON MY ROTORS WHICK PLATES AN EVEN AMOUNT OF NICKEL INSIDE AND OUT. HOWEVER I RATHER CRYO FREEZE MY ROTORS THAN PLATE THEM TO PREVENT CORROSION. AFTER I CRY FREZZE MY ROTORS THEY USUALLY LOOK RUSTY IN SOME AREAS SO WOULD BE RELUCTANT TO PLATE THEM. I MIGHT LOOK INTO PLATING THEM WITH ELECTROLESS NICKEL AND THEN HIT THEM IN THEM CRYO TANK BUT I WILL HAVE TO CHECK INTO THAT PROCEDURE FIRST.

CAD IS TOXIC. IT SHOULD WEAR OFF THE PAD SURFACE QUICKLY. BESIDES UNLESS YOUR 18" TALL AND BREATHING THE AIR THAT COMES OUT OF YOUR BRAKES AT 90 MPH I DONT THINK YOU HAVE ANYTHING TO WORRY ABOUT. THE PLATING PROCESS BY ITS NATURE IS VERY A TOXIC PROCESS. THIS COUNTRY AND ALL ITS TREE HUGGING, STAR BUCKS DRINKING RETARDS HAVE NEARLY DESTROYED THE PLATING INDUSRTY AND MANUFACTURING IN THIS COUNTRY. WE ARE SITTING HERE WATCHING OUR BUSINESS BE LOST TO CHINA. WHILE OUR WASTE WATER TREATMENTS AND ENVIROMENTAL FRENDILY PRACTICES HAVE MADE LEAPS AND BOUNDS TO MAKE THIS COUNRTY CLEANER, THE BUSINESS IS GOING TO CHINA WHERE THESE PRACTICES DO NOT EXIST AND AMERICANS DO NOT CARE AS LONG AS THEY CAN BUY THE GOODS MADE IN CHINA BY CHILDERN, DRINKIN THEIR STAR BUCKS DRIVING THEIR VOLVO BACK TO FANTASY LAND. GO AHEAD GIVE YOUR MONEY TO GREEN PEACE SO THEY CAN SAVE ANOTHER WHALE AND WATCH YOUR COUNTRY GO DOWN THE TOLIET. THIS COUNTY HAS TURNED INTO A BUNCH OF PUSSYS. YOUR MORE LIKELY TO DIE FROM EATING ALL THE FATTY FOODS THIS COUNTY HAS TO OFFER THAN IF EVERY CAR EVERY MADE HAD CAD PLATED ROTORS. ITS THAT TYPE OF ATTITUDE THAT PISSES ME OFF.