Removing surface rust / slight corrosion on a chromed steel frame?

Question

Hi all,

would anyone have any tips on removing very small patches of rust / slight corrosion on a chromed steel frame?

My only worry is that it's near the BB shelf, and so may have affected integrity at such an important area...

Thanks for any help

Answer 1

You probably have these two items at home. It works great for chrome, like bumpers on a car. Just wad some aluminum foil and dip/pour some Coke/Pepsi onto it and rub out the rust and blooms. The foil does not scratch the chrome and the acid from the soda removes the rust. Make sure to wipe it down after using this method.

Answer 2

Sure, SOS pads or steel wool and a little WD40 will remove surface rust lickety-split. Neither will harm the very hard finish.

As for that tight BB area. Use a small, flat hunk of wood like a paint brush handle etc. to work the pad in. After you clean it up see if rust is still present. If it's all clean there is no damage, if not you will need to investigate further. Lots of times oil or grease builds up in that area and will protect it.

Answer 3

It probably hasn't affected the frame strength at all unless it has eaten all the way through one of the tubes. The bottom bracket area on bikes is the toughest place to get a good coat of chrome to adhere.

As you probably know, chromium or chrome for short is layered on the frame by a process known as electroplating. Electroplating basically gives the frame a negative "charge" while the chrome solution has a positive one. Opposites attract and voila- a chrome plated frame.

However, in production issues there are some things that although aren't necessarily overlooked are very difficult to overcome on a low value part such as the typical chromed bike frame.

First is cleanliness. Surfaces must be surgically clean or the chrome don't stick. Next is a curiosity called the Faraday cage. A Faraday cage happens when a charge is applied to a particular item where several points connect... think of the inside corner of a box, or indeed, a bottom bracket. The charge jumps around and does not allow anything past it... I am finding it difficult to explain. Anyway, if the charge is too great then the chrome just can't get to the parent metal. This is common on powdercoating as well.

If the frame is a better quality one it is conceivable that the chromic acid was applied by hand then baked. This also tends to allow the chrome to "creep" away from the joints. The BEST frames are first polished to remove blemishes, then copper plated, then nickel plated, then chromed. This completely eliminates the problem but is amazingly expensive and very few companies do that kind of work. The only one I can think of offhand, in fact, is/was Somec.

Go to the auto supply shop and get a small can of Mothers Mag Polish. Best stuff on the planet.

Long answer, little information...

Answer 4

Gee whiz. Use a brillo pad. You most likely have them under your sink now. Why pour pop all over your bike - what a mess -and it won't work better the a score pad either.