Topic: Removing Chrome from aluminum parts

[Terry in Australia]

Isn't that Mentos and Diet Coke? I saw it on Mythbusters again a couple of weeks ago, does it work with Pepsi too? Cheers, Terry.

[Patrick]

I think it works with carbonated beverages in general....

[Helo229]

I think it works with carbonated beverages in general....

Indeed - it's not so much the chemicals in the pop (soda for those of you outside of PA) as it is the carbonation. The rough surface of the mentos aggitates the carbonation in the liquid and draws them into the dimples on it's surface, and makes a sort of snowball effect (little dimples attract little bubbles, little bubbles add to surface area of the mentos while retaining it's coarse surface, aggitate and draw more tiny bubbles, etc, etc).

The more carbonated a soda is, the better, I think it was either diet coke or pepsi that gave off the best results.

Not to, you know, take this topic off point or anything....

[squirley]

This is along the lines of the topic of removing chrome.  I recently purchased a rim on ebay that is brand new, chrome plated aluminum.  However, my project requires the rims to be powder coated.  I have been told that they do not like to do powder coat over chrome, but this chrome is brand new with absolutely no defects, so does this make a difference?

[mystic_1]

Anyone know of a plating shop near the northwest suburbs of Chicago that handles small jobs for chrome removal from aluminum?

Thanks

mystic_1

[Patrick]

I think the fact that the chrome is brand new will work even more against powder coat, Squirley. Powdercoating, which was invented by an Australian, is really a coating of melted plastic. The powdercoat needs a rough surface to cling to. You would be better off with an old rim you could sand down if you are going to powder coat.

I have powderoated many of the small parts on all my bikes. The older, rougher stuff holds much better, The new shiny stuff chips easily because the powder coat is sticking only to itself. Powder coat is actually very good at filling in pitting and rough areas because it melts and cools smooth.

Patrick

[squirley]

I was looking at it more as the idea that it has a uniform finish that has no gouges or dings, and that I would just sand it down a little before coating.  Does it need to be totally removed before?

[Patrick]

If not removed, at least roughed up. The smoothness of the finish is the culprit, plus the fact that chrome is non adhesive in the first place. A smooth shiny surface offers little purchase. Before I powder coat a part I like to soak it for a little while in an acid bath to rough up the surface and give the powder good footing.

[Terry in Australia]

Don't try to powder coat over chrome mate, and sanding it will have little effect as far as adhesion is concerned.

Take it to a platers and have them remove the chrome in a reversing bath, so the aluminum rim is not damaged, then have it coated, or, like Patrick suggests, get rid of that rim, and just get an old rim blasted and coated, the powder will fill the pits and make it like new. Cheers, Terry.