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Best Option: Polished Aluminum, chrome Plating, or Powder Coat for Engine Intake Manifold?

Working on a hot rod and putting an SHO motor under the hood. The SHO motor has a beautiful aluminum, crossover manifold we'd like to accentuate.

We'd love to just have it polished but are concerned that the heat from the motor, along with time, will tarnish the aluminum. What can we do to prevent this from happening or at least lessen the amount of maintenance in keeping the polished aluminum looking bright?

Is polishing the aluminium the wrong option? Chrome-like powder coat better?

Please help.

Thank you in advance!

James Kissell
Car Restorer - Mona, Utah, USA
June 4, 2011

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June 29, 2011

Good evening,

Just found your post and figured since there has yet to be a response I would answer this for you from my own experience.

Option One- Polished aluminum.

Cheapest and easiest way to go. If its just a base aluminum right now you will need to sand the piece completely from about 240 grit up 800 or higher. Best to do this with a powered sander. Then polish it like normal. I would recommend Jackson Lea polish with a yellow wheel at about 4500 rpm. Give it a really good scrubbing and then you will have a good polished surface.

Downside- will tarnish over time, the more you use the vehicle the quicker it will happen due to the heat. You will have to polish but not as extensively. The maintenance polish can be done by hand with a rag and some Autosol ⇦this on eBay or Amazon [affil links] -- a little goes a long way with this stuff.

Chrome plating- A little more expensive, but easier on the upkeep. Will still need a little hand buffing with some Autosol or similar polish from time to time but not as much as the aluminum that has been polished. You will have to send the piece out to be chrome plated and this can take weeks.

Powder Coating- Most durable and most expensive. Little to upkeep but will not get as nice of a finish if the rest of the car has the polished chrome look. But best if you are going to be running the car for extended periods of time.

This is my personal thoughts on these from my own experience working on transports. I don't do many Hotrods but the application is the same. Hope this helps and good luck with the project.

Andrew Colley
- Windsor, Ontario, Canada

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What temperature will your manifold get to? It is possible to be too hot for powdercoating.
I don't think powdercoating would be much good over about 250° C, unless you use one of the special high temperature powders, and then there'd still be a limit.
But polishing doesn't have a limit, as its not a coating. The limit of the base metal is the limit, except that temperature might quicken the tarnishing.

Geoff Crowley
Crithwood Ltd.
Westfield, Scotland, UK

June 30, 2011

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Polishing will look good and cost only your labor but will require ongoing touch up polishing.

Chrome plating won't be cheap if done right, but will look like a million dollars and last forever (again IF done right), and will need nothing more than an occasional wipe.

Jeffrey Holmes, CEF
Spartanburg, South Carolina
July 1, 2011

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Ed. note: We have many threads about polishing aluminum, chrome plating it, or powder coating it if you search the site ... but thread 22096 is specifically about polishing manifolds.