Case corrosion.

The screenshots you have posted show pitting. It's believed to be caused by the pH of some users sweat causing a reaction to the paintwork. Its been around as a complaint since the days of the PowerBook, but only effects some individuals (my old PowerBook G4 for example had none after years of faithful service, so thankfully my sweat doesn't peel the paint on Apple Pro laptops 🙂 ). Options are to live with it (it's cosmetic issue), or to consider keyboard/wrist protectors. below is an example of one such protector (I think you can simply cut out of PVC yourself if you wish to save some money):

http://www.marware.com/PRODUCTS/Apple-Laptop-Products/Protection-Pack-for-MacBoo k-Pro

I really like the Marware protection pack. In my opinion it is a must have!

You can buy a new case from http://www.ifixit.com/ for $250 or you can buy the Marware cover for $15.

You could try, but I'm not sure how satisfactory the results would be. Aluminum is often anodized prior to painting, but you would still need to use a zinc chromate primer for best results with regular paint. For a really good surface, you would probably want to use an epoxy type paint, and I believe that epoxy would take its own special primer. And for best results, you would probably want to disassemble the computer and extract the metal part that you wanted to paint.

The surface is actually hard anodized aluminum. By its nature, the anodized surface is just a few ten thousandths of an inch thick and hard but brittle. For that reason, it will develop microscopic cracks under a heating and cooling cycle which will allow for the intrusion of reactive substances, in this case individual body chemistry. Aluminum is very active and therefore very reactive. The anodized surface is basically aluminum oxide, which is generally very protective. However, for a few unfortunate individuals, the sweat can penetrate the surface through the microscopic cracks and produce the characteristic black pitting.

The anodized surface is generally more durable than a painted surface would be--that's why it is used. I'm not sure that you would be happy with a paint job over time.

So it might boil down to a protection pack, a new upper case, or the pits.

Good luck!

as far as i can tell the case is powder coated (if you look closely at the case in bright light you can see little bits that are multi colored, anodizing does not give this). also if it is anodized it would not be "hard" anodizing it would be a class 2 ano. class 3 aka "hard" will only give a very very dark color (black, deep forest green or deep navy blue, at least from all the research i have done) and hard coat will not scratch as easily as the coating can as well.

anodizing will not react the ways i have seen the chipping happen on the machines (anodizing will not chip it will wear down or scratch but you wont be able to chip it off).

anodizing will also not react especially with the ph of body oils. it is used in industrial applications where it is dealing with much more extreme ph levels (IIRC the acid % used in anodizing and in stripping ano is 8-12% sulfuric acid)

end rant (sorry but i am rather stubborn when it comes to arguments and from what i see and can tell this does not act like anodizing)

call apple, i think they will at least take a look at it because they would classify it as a flaw in teh material.

-matt

I am partly going by a quote I read of Steve Jobs saying that the MBP case is "hard anodized aircraft grade aluminum" or something like that. I don't see how his legal team would allow him to say that if it were in fact powder coating.

I don't really see the little bits that are multi colored, but I think my eyes are a few decades older than yours, so that could just be my bad eyes. And I might also say I have heard the term "hard anodizing" used pretty loosely. My understanding of "hard" anodizing is that it has more to do with the thickness of the anodizing and not so much with the color, which is more dependent on other factors like the chemical bath and current.

To me, the MBP looks like clear anodized aluminum. I don't know if it would technically be considered "hard" or not by an anodizer. But even a hard anodized surface would be considered slightly porous, and this black pitting has come up time and time again in conjunction with a few individuals body chemistry.

The aluminum oxide which makes up the anodized coating is not what reacts. It is the skin oils and salts penetrating this very thin coating and getting to the underlying aluminum. I don't know what the chemistry would be--maybe someone else does--but I would expect it is the salt in the sweat that is causing the problem.

The pictures I have seen show what looks like black pits, which is not what I would expect to see with powder coating. Powder coating would be thicker--a common application is white ware like washers and dryers. If it were powder coating, I would expect to see staining or chipping rather than pitting.

I'm stubborn too, and there's nothing I like better than a good debate over metal finishing. It would be a lot better if we could look at the thing in person and decide. But since we don't have that option, I'm happy to debate it in the abstract.

I think Alu spray paint (might want to be careful about the exact color) applied to the pits might work as a solution (won't be very expensive). The other way to go is to contact independent Apple service provider and ask about ordering a replacement top case, may be able to get one at not too high a price. Looking online top case seems to be around $250 (parts and installation in this example):

http://www.dttservice.com/macbookpro.html

while you are correct about the color being dyed after the layer is developed from some reason the thickness makes the colors much darker or something. i never understood why it was but on an anodizing sight that explained the different classes that was what was listed.

while the layer is porous it gets sealed when finished (but it may still remain porous slightly) i dont think body oils should be able to penetrate down unless the ano was poor quality. my inital anodizing info came from paintball (99* of the markers are anodized) and if body ph would be able to penetrate down and do this then paint that was not cleaned off a marker should be able to penetrate and stain, which it wont do.

all the matte finished parts i see have a much more frosted feel. also if the aluminium is "aircraft grade" it is probably a 6000 series (6061 is pretty common if i remember right) and that alloy doesnt oxidize as fast or as deep as others (again IIRC).

i dont remember if it was you or some one else that had mentioned something about the strip in front of the KB being differant. that is what i had chip on me so i may be using that as a backing for nothing.

but from seeing my friends machines after they drop them and have the corners chip i just dont see how ano will react that way, i can take a piece of anodized aluminum wire and twist it and the only thing that can happen is it will wear thin from being stretched

i think we need to make friends with an engineer at apple
-matt

while the layer is porous it gets sealed when finished (but it may still remain porous slightly) i dont think body oils should be able to penetrate down unless the ano was poor quality.

The sweat from some indivduals is more caustic than others, but it is a gradual abrasive process as the user rests their hands on the case. Apple laptops have been using this type of anodized finish ( paint ) for years now, and the pitting problem became apparent about 6 months or so after initial Alu PowerBook release. There are paint sprays that work for the anodized look, so user can go this route over new top case if they find a good match.

either way, if it is ano, the ones that get pitting have substantial flaws in the process/material

idk, but there are a lot of things that make me really wonder how it can be anodizing, the more i look at this i am thinking powdercoating may not be it either but i just cant see how ano would react like that, if it was an over all area maybe but the pitting is just to weird

-matt

Message was edited by: mattathayde

I have seen numerous posted pictures of similar black pits on both the MBP and PowerBook forums, and it's always in an area that has had prolonged skin contact like an area of the palm rest, and then only for a few rare individuals. And I agree it is weird--not something you expect to have with an anodized finish. But it's obviously happening. Maybe to just one individual in 1000--or 10,000. But still a small number.

I'm not sure just how they produce the matte finish. I am most familiar with 6061 T6 aluminum, which is what we used in our shop. We made parts from aluminum plate and then did an orbital sanding followed by a bead blast and etching prior to anodizing to produce a similar finish. The Apple case parts look like they were made in a form die, and also look to be quite thin. So I don't think they could have done a bead blast because of the distortion that would have been introduced. But it is possible that there was some sort of an abrasive process followed by an etching process.

However Apple does it, it is a beautiful finish! I agree with making friends with an engineer!

it is a nice finish, i wont argue that. im just not sure how you can get a finnish that feels as smooth yet looks as matte. maybe im just used to people beadblasting to get the matte finish. something i saw that does confuse: a friend dropped her MBP and the top casing kind of popped out but the edge of the top piece of the top casing (that has that finish) looked to be bare AL.

i checked out the different pieces under a hard light that really shows the thing i was talking about and for the life of me i cant see any difference between any of the keys, top case, or the strips.

idk this debate is really getting to me because for anything that points to one side there is something else that is making me think it cannot be that finish
-matt

My MBP has a tiny flaw where there is a bulge above the latch button and I can see the edge of the bottom casing, and it looks like it is anodized to me. It is possible that the visible side has some sort of an abrasive treatment that produces the matte finish and the other surfaces just receive the etching and whatever else is done during the process. That way the appearance could be somewhat different on the outside of the case which you can see and on the inside which you can't see. But if in fact the inside really is just bare aluminum, then your point is well taken, as anodizing produces a coating on all surfaces and not just one side. Since I think both of our Macs are still under warranty, we're not going to be taking them apart any time soon just to find out how the inside of the casing is finished. But I must confess, this debate has gotten my curiosity up.

ya, i was trying to look at the service PDF but the pics are not good enough to really see the difference if there is any plus the whole sub structure blocking 95% of the bottom

hmm http://individual.utoronto.ca/kkapoor/macbook-pro.pdf look at page 36, i think you can see the under side of the top case and it looks like it is shinny (the holes in the sub structure) so if so, they either masked off the under side or we have a weird finnish. the fact that some are getting shocked at the edge also makes me wonder since anodizing is supposed to be an insulator

-matt

Message was edited by: mattathayde