Cadillac & LaSalle Club Discussion Forum

Cadillac & LaSalle Club Forums => Technical / Authenticity => Topic started by: Ross Morgan #22943 on May 07, 2009, 05:55:47 AM

Title: 57 Brougham - Chrome plating Aluminium bumpers?
Post by: Ross Morgan #22943 on May 07, 2009, 05:55:47 AM
I'm looking at casting the rear bumpers on a '57 Brougham (mine are very pitted) and one of the materials the foundry can use is aluminium. Does anyone know if there are difficulties in choming this metal and it lasting?  I will ask the local plating shop but I wanted to get some feedback from the forum.  Thanks!  Ross.
Title: Re: 57 Brougham - Chrome plating Aluminium bumpers?
Post by: Otto Skorzeny on May 07, 2009, 11:16:44 AM
Use the search function above on this forum to find a recent lengthy discussion on the subject. A couple vendors were listed. It's a complex and expensive process.
Title: Re: 57 Brougham - Chrome plating Aluminium bumpers?
Post by: Ross Morgan #22943 on May 07, 2009, 08:57:02 PM
  For some reason, I was thinking the bumpers were an aluminium alloy but reading the thread http://www.cadillaclasalleclub.org/forum/index.php/topic,104460.0.html   , it appears that they are aluminium.  Good news though that with careful selection of a plater, chrome plating aluminium can be done with long term success.  Regards, Ross.
Title: Re: 57 Brougham - Chrome plating Aluminium bumpers?
Post by: Walter Youshock on May 07, 2009, 09:08:08 PM
They were sand-cast aluminum, as were the wheels.  Saber wheels and the bumper ends on '55-'58 Eldorados were also like that.

The plating process is very different.  Decent originals in the hands of an inexperienced platers will melt in the wrong solutions.
Title: Re: 57 Brougham - Chrome plating Aluminium bumpers?
Post by: Whit Otis, 1188 on May 07, 2009, 10:16:56 PM
I believe the wheels were forged light alloy, not a casting, in order to have the strength to endure the lateral stress that wheels experience on turns.  Also, I forget for sure, but the center hub was not a light alloy forging.... anyone know for sure?
Whit Otis
Title: Re: 57 Brougham - Chrome plating Aluminium bumpers?
Post by: Mike Josephic CLC #3877 on May 08, 2009, 12:06:38 AM
These were hybrid units.

The outer part of the wheel was an aluminum alloy (once piece including the center hub)
that was riveted to a steel inner wheel.  That's how all of the sabres were made starting in
1955 until the end of production.  The riveting process changed, the dimensions of the inner
steel wheel also changed (starting in 1957) to accomodate larger brakes. Kelsey
Hayes made them for Cadillac with technology from Alcoa for the aluminum issues.

I have a few spares in my basement and 5 restored ones in my 1955 Eldorado. 
BTW, they can be replated nicely by somebody who knows what they are doing.
Recommendation:  Valley Wire Wheel in California.  They are expensive ($1,000 per
wheel) but you will not regret it.  I had mine done 3 years ago and not a sign of a
pit, flaking chrome or any other problem.  Yes, they hold air well even with tubeless
tires as they should (they were designed for that).

Mike
Title: Re: 57 Brougham - Chrome plating Aluminium bumpers?
Post by: Peter Nieuwlandt on May 08, 2009, 03:26:13 PM
Of course Mike is rigth on the Sabres .These wheels consist of 2 parts and are rivited together.
I've found that not many people know how to disassemble and reassemble the Sabres,but the Porsche guys can help You out because the 911 model uses exactly the same type wheels .

Peter