Refurbishing Reflectors: Chrome vs. Aluminum

[jaudette3]

I posted this in a Services Offered thread I have in the FS Parts section and Peter thought it would be a good idea to cross post it here in the Technical Section.

I'm sometimes asked about refurbishing reflectors by chroming them as opposed to the vapor deposited aluminum process. Chroming is a lot simpler as the process can be done a single plater as opposed to aluminum which requires having the reflectors prepared by one plater - copper -> nickel -> polishing - then sent to a second plater for the vapor deposited aluminum process. Also, it's much cheaper to just chrome plate them and the aluminum process is expensive.

The reason? Chrome just doesn't work very well. Using silver as the standard for reflectivity, vapor deposited aluminum is 95.6% as reflective as silver, while chrome is 63.5% as reflective as silver. You lose almost 1/3 of the light with chrome as opposed to aluminum. Here are the numbers:



Reflectance Comparison
Silver: .95512 = 100%
Aluminum: .91320 = 95.6%
Chrome: .60604 = 63.5%

Source:
Refractive Index
http://refractiveindex.info/?shelf=m...=Cr&page=Rakic

The central point of H1's is their shear brilliance. When done right they are flame throwers. It kind of defeats the purpose to decrease the light by a third with chrome plating. Vapor deposited aluminum, the process used by all modern automotive manufacturers, is the best way to go at this time.

Cheers,
John

[72targa]

Thanks John. The chemist in me finds this really interesting. And yes, I do have a degree in Chemistry!

[jaudette3]

Me too. I really geek out on this stuff. I think we'd be called anoraks in England.