That is rust or iron oxide from the inner surface of the steerer. Luckily, an anodized aluminum surface like your Technomic Deluxe stem is pretty tough. Some vinegar and fine steel wool should remove it without any further damage to the anodized surface. If yours was a regular Technomic, it probably wouldn't be anodized, and thus could be scratched by the steel wool. To prevent problems like this in the future, it is important to grease the inside of the steerer before assembly. (A regular, non-anodized stem would be even worse, as the aluminum-steel interface sets you up for galvanic corrosion. In that case, the stem would be attacked preferentially, leading to large volumes of aluminum oxide, and possibly a stuck stem in bad cases.)
Cameron Murphy San Marcos, CA On Sunday, October 16, 2016 at 12:29:46 PM UTC-7, Lungimsam wrote: > > Came off my Sam. Exposed stem is clean as you can see.clean. Stem sunk > into steerer tube has some surface corrosion of some sort on the aluminum > Technomic deluxe them. How do I get the corrosion off the stem and restore > it to its original lustre? -- You received this message because you are subscribed to the Google Groups "RBW Owners Bunch" group. To unsubscribe from this group and stop receiving emails from it, send an email to rbw-owners-bunch+unsubscr...@googlegroups.com. To post to this group, send email to rbw-owners-bunch@googlegroups.com. Visit this group at https://groups.google.com/group/rbw-owners-bunch. For more options, visit https://groups.google.com/d/optout.
