tiny rust spot on Unibody MBP

Discussion in 'MacBook Pro' started by sn0warmy, May 1, 2009.

  1. sn0warmy macrumors 6502a

    sn0warmy

    Joined:
    Mar 26, 2009
    Location:
    Denver, CO
    #1
    The day I bought my Unibody MBP I bought/installed the "Power Support Protection Pack":

    http://store.apple.com/us/product/TV054LL/A?mco=NTAwMjgzNw

    it was great, but I decided to start using this RadTech screen protector instead:

    http://www.radtech.us/Products/NotebookScreensavRz.aspx

    After removing the Power support piece surrounding the keyboard, I immediately noticed two tiny rust spots on the computer :
    [​IMG]
    [​IMG]

    These pictures don't do it justice at all. The spot was noticeable to all 3 people who immediately looked at my computer and said "what's that brownish red spot?"

    I understand that aluminum does not rust. But it does show rust stains. Has anyone else had this problem? And does anyone know of a nice safe way to remove a rust stain from this kind of aluminum?

    thanks,
    Kevin
     
  2. GGJstudios macrumors Westmere

    GGJstudios

    Joined:
    May 16, 2008
  3. drewsof07 macrumors 68000

    drewsof07

    Joined:
    Oct 30, 2006
    Location:
    Ohio
    #3
    Though it does oxidize. But I'm thinking Aluminum Oxide is white :confused: Anyone know how the anodizing process could cause this? I've seen alu powerbooks that have a similar "cavity" where the anodized portion is missing and left with bits of brown that look like rust.

    Perhaps a friction based scrubber, such as the "magic eraser" could work. I've used those on iBooks and MacBooks before, but not on aluminum. Use it cautiously of course ;)
     
  4. GGJstudios macrumors Westmere

    GGJstudios

    Joined:
    May 16, 2008
    #4
    Reddish-brown rust only occurs with ferrous metals and never occurs with any form of aluminum. My guess is the spots are something else that can be cleaned off. There's no way it's the aluminum, anodized or not, since aluminum oxide is whitish, as you said.
     
  5. kastenbrust macrumors 68030

    kastenbrust

    Joined:
    Dec 26, 2008
    Location:
    North Korea
    #5
    This isn't rust this is dirt, thats why people buy these:

    [​IMG]
    http://www.moshimonde.com/palmguard.htm

    A) Aluminium cant rust, it can oxidize but thats white

    B) It cant be burned because the computer would have to be running at 660C to do that

    If you want to get rid of it, try using a gentle aluminium cleaner, theres no protective layer on the aluminium so you dont have to worry about anything like that.
     
  6. Kronie macrumors 6502a

    Kronie

    Joined:
    Dec 4, 2008
    #6
    It could be the anodizing scraping off.
    I have a teeny tiny spot on the corner lid that looks like the rust. I think its the anodizing coming away.
     
  7. mikes70mustang macrumors 68000

    mikes70mustang

    Joined:
    Nov 14, 2008
    Location:
    US
    #7
    seriously? take it to a genius, better get a new one, looks ruined :rolleyes:
     
  8. shoulin333 macrumors 6502a

    Joined:
    Jun 26, 2007
    Location:
    California
    #8
    iron oxide = rust = red/orange

    iron oxide = doesnt exist on Aluminum

    This is why our street signs don't rust :)
     
  9. GGJstudios macrumors Westmere

    GGJstudios

    Joined:
    May 16, 2008
    #9
    That's not possible. Even if the anodizing were not there, the aluminum underneath is silver colored... whitish if oxidized, so there's nothing reddish-brown anywhere on a Mac enclosure.
    Yes, I already said that. Try reading the whole thread.
     
  10. miles01110 macrumors Core

    miles01110

    Joined:
    Jul 24, 2006
    Location:
    The Ivory Tower (I'm not coming down)
    #10
    Macbook Pros aren't anodized, they're powder-coated. Not that this fact changes anything related to your dirt problem.
     
  11. GGJstudios macrumors Westmere

    GGJstudios

    Joined:
    May 16, 2008
    #11
    I've been searching, but can't find anything that says the MBP is powder-coated. On Apple's site, I do find the fact that the Apple Wireless Keyboard, the iMac, the Mac Pro, Apple Cinema Displays, etc. are anodized, so I'm interested to know where it says the MBPs are different. Have a link?
     
  12. Kronie macrumors 6502a

    Kronie

    Joined:
    Dec 4, 2008
    #12
    Well mine still has this corrosion, whatever it is:

    [​IMG]

    Granted its tiny but the anodizing is doing something and there seems to be some brownish, rough, something underneath. It looks like rust. I know its not rust and I also know I didn't bump or scrape the lid on anything.

    My wife is an art teacher and she gave me this:

    [​IMG]

    What I found out is that this silver metallic paint when painted on a UMBP looks just like the original finish. I didn't paint the corner yet because I'm waiting to see if my spot gets bigger. If it grows more I'm going to have apple take a look at it.
     
  13. TheMonarch macrumors 65816

    TheMonarch

    Joined:
    May 6, 2005
    Location:
    Bay Area
    #13
    That spot is corrosion from something rubbing or impacting on the anodized aluminum. I have two spots on mine [Unibody], one of which is exactly where Kronie has his. My G5 also has a couple of spots on the handles.

    I can tell you from experience, its not going to go away :(. But if its any consolation, its not going to get worse either. I highly doubt Apple will do anything about it, as the affected piece is probably the most expensive part of the entire computer. It couldn't hurt to try though.
     
  14. mikes70mustang macrumors 68000

    mikes70mustang

    Joined:
    Nov 14, 2008
    Location:
    US
    #14
    But really, its a freaking speck. Thats not going to affect resell. And oxidation on Aluminum is white. Not brown or what ever. Unless you got a steel metal flake on there in a humid room...i reallly doubt its a rust spot. Just a stain, you didnt effectively clean the palm area b4 putting the protector on and it got mashed down and it stained it. If it wont wipe off with iklear or mild soap then stick a palmguard on it and move on.
     
  15. miles01110 macrumors Core

    miles01110

    Joined:
    Jul 24, 2006
    Location:
    The Ivory Tower (I'm not coming down)
    #15
    They say they're anodized, but anodized surfaces have a different texture than the surface of those items (anodized surfaces are much smoother and harder). Anodized surfaces do not wear down like this. In fact without blunt pressure they don't wear down virtually at all.

    So yeah, unfortunately I can't provide any hard evidence other than my experience with anodized surfaces used in electronic assemblies.
     
  16. war eagle macrumors 6502a

    Joined:
    Jul 24, 2008
  17. GGJstudios macrumors Westmere

    GGJstudios

    Joined:
    May 16, 2008
    #17
    Anodizing makes aluminum oxidation-resistant, but you can't tell anodized from non-anodized by touch; only by oxidation. From all the evidence I can find, Apple ONLY uses anodized aluminum:

    http://www.apple.com/macbookair/design.html
    http://www.apple.com/lae/displays/cinema/design.html
    http://www.apple.com/keyboard/
    http://www.apple.com/imac/design.html
    http://www.apple.com/macmini/design.html
     
  18. miles01110 macrumors Core

    miles01110

    Joined:
    Jul 24, 2006
    Location:
    The Ivory Tower (I'm not coming down)
    #18
    Marketing dictates that "anodized" aluminum is advertised instead of "powder-coated" aluminum. As an analogy, Apple also reports drive space in decimal capacity, which isn't technically correct either, especially since the simple reality of computers demands that the operating system reports capacity in binary. Is it "wrong" in the absolute sense? No. But it's not 100% accurate.

    It could be argued that powder coating is a specialized form of anodization, but in reality they have significant physical differences in the final product.
     
  19. Kronie macrumors 6502a

    Kronie

    Joined:
    Dec 4, 2008
    #19
    I always thought these were some kind of powder paint and not truly anodized. Powder paint makes more sense because its way stronger and wont come off as easily.
     
  20. GGJstudios macrumors Westmere

    GGJstudios

    Joined:
    May 16, 2008
    #20
    It's not a matter of marketing. The two are different processes. If Apple powder coated, they would say so. If they say anodized, then it's anodized. The two are not interchangeable terms.
    Most computer and hard drive manufacturers do the same and, like Apple, they usually clarify their terminology, to avoid confusion:
    Anything can be argued, but that doesn't make it true. Powder coating is not a form of anodization. If you take the time to learn what they are, you'd know they're completely different.
    Actually, powder coating comes off easier than anodization.
     
  21. Gonzo3333 macrumors 6502a

    Gonzo3333

    Joined:
    Mar 30, 2009
    Location:
    Chicago, IL
    #21
    Try gently rubbing a Scotch Brite pad on the mark, I think that would take care of the problem.
     
  22. JBazz macrumors 6502

    Joined:
    Apr 14, 2006
    #22
    That is not corrosion. It appears to be where the finish has chipped off. As has been posted here already, aluminum corrosion is white and powdery in the beginning. When it spreads deeper, the metal will appear swollen and flaky. I am well versed in corrosion and corrosion prevention.

    If it were corrosion, the correct thing to do would be to remove it so it doesnt spread. But it is not, it is surface finish damage and scotch brighting it will only do further damage. Touch up painting is acceptable only because it is not corrosion.
     
  23. Kronie macrumors 6502a

    Kronie

    Joined:
    Dec 4, 2008
    #23
    I disagree. I have worked with metals for years as a metal fabricator and powder coating is much much tougher than anodized aluminum. I don't think you CAN powder paint aluminum though, only steel. It wont stick on aluminum the right way. That's why if you want to color aluminum you anodize it.

    I also don't think whatever process apple uses to finish there Macbook line is just anodizing either. There is something else done to it. I have seen lots and lots of anodized parts and nothing ever looked like a Macbook pro finish.
     
  24. miles01110 macrumors Core

    miles01110

    Joined:
    Jul 24, 2006
    Location:
    The Ivory Tower (I'm not coming down)
    #24
    Two different processes that use more or less the same physical principle to adhere a coating to a metal surface. Like I said, they're "different", but it doesn't take a major stretch of imagination to consider one a subset of the other. And I never said they're interchangeable, just that Apple is using the wrong term. It's clearly not anodized.

    So because "most computer and hard drive manufacturers do the same", it makes it true? This is funny, considering what you say below...

    Right, like powder coating vs. anodization, and binary vs. decimal representation of capacity. I know you're a huge fanboy and take everything Apple says as gospel, but you need to face reality in some situations (like this one) that your beloved company is not telling you the full story.
     
  25. PeterQC macrumors 6502a

    PeterQC

    Joined:
    Jun 30, 2008
    #25
    They probably sandblast the body before anodizing it.
     

Share This Page