Along the lines of earlier comments, in the distant past I worked with the Forest Service cleaning out backcountry campfire pits where folks had burned aluminum foil packages that had held food. These were not very attractive or aesthetic additions to the wilderness, those small bits of aluminum foil were very hard to remove from the ashes, so we experimented with lye as a way to eliminate the shiny aluminum bits, which worked, but may have left behind some strong base deposits in the wilderness in addition to some aluminum hydroxide... the moral to the story being that care with the concentration of lye is in order, since lye will dissolve aluminum. Dilute, then more concentrated solutions if necessary, followed by a good flushing with lots of water might be the ticket. Lots of personal protection as well: lye will dissolve proteins much better than aluminum, including eye, lung, and skin! Go slow, less is more, etc...
Bill Gibson, in Tempe, AZ, USA
On 7/10/07, Jan Heine <heine94@earthlink.net> wrote:
> I tried oven cleaner, but the environmentally safe stuff doesn't
> remove any anodizing (perhaps a good thing, too?). Lye can be found
> in hardware stores, and while it's caustic, I am not aware of great
> environmental dangers. The only problem is that the smallest size
> they sell will de-anodize more bike parts than you'll ever accumulate!
>
> The process is the same as described below, except I just wipe off
> the anodizing with a paper towel. BTW, a plastic container (yoghurt
> cup) is perfect for the bath. Don't use metal!
>
> Jan Heine
> Editor
> Bicycle Quarterly
> 140 Lakeside Ave #C
> Seattle WA 98122
> http://www.bikequarterly.com
>
> >Ray Dobbins has some info on this at his website. Here is what he says
> >about removing anodizing so you can polish aluminum parts:
> >
> >"If your part is anodized, you must remove the anodizing before you can
> >polish the part. I remove it with Easy-Off oven cleaner spray (the
> >heavy-duty one, not the new no-odor one), which has lye as its main
> >ingredient. Use regular dishwasing gloves (not just latex or thin vinyl
> >because the lye will eat right through them), and work outdoors because the
> >fumes are very powerful (they will knock you back!). I place the part in a
> >plastic container and then I spray the Easy-Off liberally over the part. I
> >let it sit for no more than 3-5 minutes (otherwise the lye may start to eat
> >away at the aluminum and cause pitting). Then I scrub it real well with
> >super fine steel wool (#0000 grade) to make sure I get all the anodizing
> >off. Then I wash the part with Simple-Green, rinse it thoroughly with warm
> >water and dry it off. This whole process will leave the aluminum very
> >dull, but that's OK (don't freak out), because it'll shine right up once
> >you start polishing."
> >
> >You can read more, and see the results on Ray's page at:
> >http://www.raydobbins.com/ -- He has some great photos on his site.
> >
> >I've also heard of people mixing a mild lye solution to soak the parts (dry
> >Drano + water), but the Easy Off method sounds a little easier and safer.
> >
> >By the way, I would NOT recommend spraying the parts with Easy Off and then
> >putting them in the oven! If I'm not mistaken, you could have a risk of
> >fire or explosion from combining the fumes with the heat of the oven. In
> >fact, while I don't have a can of the stuff handy so I can verify this, but
> >I'm almost certain that there is a warning on the can about using Easy-Off
> >in a hot oven, or turning the oven on after spraying it inside. The
> >reaction between lye and aluminum works at room temperature, and as far as
> >I know, does not need extra heat to improve the results.
> >
> >Kyle Brooks
> >Akron, OH
> >
> >
> >> [Original Message]
> >> From: Jerome & Elizabeth Moos <jerrymoos@sbcglobal.net>
> >> To: <loudeeter@aol.com>; <classicrendezvous@bikelist.org>
> >> Date: 7/10/2007 10:23:24 AM
> >> Subject: [CR]Removing Annodized Finish
> >>
> >> I have a couple of Blackburn racks anodized black. Never liked the black
> >as well as silver, partly because small scratches are more evident on the
> >black racks. Anyone know a way of removing the black anodized finish,
> >other than sanding it off? If not, anyone had good results respraying
> >these black with spraycan paint to cover the scratches?
> >>
> >> Regards,
> >>
> >> Jerry Moos
> >> Big Spring, TX
> >>
> >>
> >>
> >> --- StripMime Report -- processed MIME parts ---
> >> multipart/alternative
> >> text/plain (text body -- kept)
> >> text/html
> >> ---
> >> _______________________________________________
> >> Classicrendezvous mailing list
> >> Classicrendezvous@bikelist.org
> >> http://www.bikelist.org/
>
> _______________________________________________
>
--
Bill Gibson
Tempe, Arizona, USA