Alluminum housing durability?

I really liked the plastic on the iBook I had.

So far I haven't had any issues with the MBP's case. No dents or scratches.

a friend of mine dropped a 9lb _DISCO BALL_ on his girlfriend's PowerBook while trying to hang it on the ceiling. PowerBook was open and the disco ball fell right where SuperDrive is. The case, keyboard, touchpad and SuperDrive are pretty much ruined, however, PB still works fine with USB keyboard and a mouse. Disco ball was left undamaged!

Saturday Night Fever meets Disco Inferno! lol

So yeah, the case is pretty durable. 9lb. anything falling from a 8ft. height is alot of force.

Just check on www.matweb.com for the Young's modulus of plastic (you should look for ABS) and of aluminium. The higher it is, the less you are having problems with scratches etc... the only thing is that if plastic gets scratched you don't notice it as much as in the case of a metallic material... but you should know that plastic has a much higher elastic limits which meens that if you deform it, it's swapping to it's initial form after releasing strains...
thats's all

Google "powerbook pitting". It seems that plastic wears out and still looks fine, whereas with aluminum it's the paint that covers the aluminum that wears out. That's the only thing I'd be afraid of if I were afraid of anything.

Young's modulus relates to stiffness, which is definitely relevant for long-term durability, but not necessarily relevant for scratch-resistance...

for scratch resistance, one needs to compare ABS and aluminum on a Hardness scale (e.g. Shore)... most plastics are shore hardness <30, while brasses and aluminum alloys are >50....

oh and BTW, i thought the aluminum casings on Macs were anodized, not painted, but i could be wrong there.

let me clean up my hardness numbers (i was unclear)...

"Brinell Hardness" is
< ~30 for plastics (Shore "A" scale from 0 to 100)
~50 to ~80 for aluminum alloys (Shore "B" scale from 0 to 100)
~8000 for diamond

same point though - aluminum should be stiffer and more scratch-resistant than ABS. the anodization is of course a separate issue...
another difference between ABS cases and aluminum/Titanium cases is that metal is in general a much better thermal conductor than is plastic. so, metal cases dissipate internally-generated heat more efficiently than plastic cases - which should also mean better long-term durability (at a cost of a slightly warmer exterior)... cheers

Nice for going more to the details... but as it isn't very popular to talk about all that stuff, I just didn't want to complicate the thing more than necessary ;o)

empirical (not very scientific) you may consider young modulus to see if it "could" be more resistent to scratches or not... But of course you're answer is right. Oh yeah in europe we prefer to use Vickers :op

Just check on www.matweb.com for the Young's modulus
of plastic (you should look for ABS) and of
aluminium. The higher it is, the less you are having
problems with scratches etc... the only thing is that
if plastic gets scratched you don't notice it as much
as in the case of a metallic material... but you
should know that plastic has a much higher elastic
limits which meens that if you deform it, it's
swapping to it's initial form after releasing
strains...
thats's all

I thought the iBook casings were made of polycarbonate, not ABS... I don't know about the 4-year-old iBooks.

Even though plastic will go to higher strain before permanently (plastically) deforming, it takes a lot more force/stress to get most metals to yield than plastics, as given by the Young's (tensile) modulus, though shear or flexural forces is more likely what your computer will experience... unless you have a tug-of-war with your laptop... but the different moduli are somewhat related.

As others have noted, hardness will tell you about scratch resistance. Unless you're throwing disco balls at your computer, I don't think you have to worry much about tensile or shear strength. Anything that will physically deform your computer should be guarded against by you, not by the casing.

The aluminum case is not anodized, but rather painted silver. Anodizing would add too much to the cost and can be scratched, leaving a shinny bare aluminum mark. Anodizing can also be effected by the acid in some peoples fingers, leaving unsightly areas. This would be a warranty nightmare for Apple and probably the reason (along with cost) they go with paint. Paint can also be touched up with fair to good results pretty easily. Try repairing a scratch in anodizing.

I've seen the plastic (ABS?) cases take some pretty heavy abuse and shrug it off. Powerbooks and MacBooks usually fail after a drop, even of just a few feet.

The aluminum case is not anodized, but rather painted
silver.

k - thanks.... i suspected anodization becuase my dual G5 tower is anodized aluminum.... but for the reasons you mentioned this probably is only an option on s'th non-portable... cheers

The aluminum is not painted. The titaniums were painted though. Where did you get that information?

The outer top cover is bare or lightly sealed aluminum. The area around the keyboard, track-pad etc. has some type of "coating" as well. You may prefer to call it a sealant or paint, but it is not bare aluminum. The bottom probably has a clear sealant to protect the surface from wear. I got an email from ColorWare confirming my suspicions when I asked about their painting process.

http://www.colorwarepc.com/products/select_macbook.aspx#Tab

According to the MacBook Pro information booklet, the case is made from hardened anodized aluminum. The anodized coating provides far superior protection to the aluminum surface than painting. The titanium powerbooks were painted. Titanium is much stronger than aluminum by weight, but is also more expensive and does not lend itself to anodizing the way aluminum does. This is why the Ti books were painted.

I personally wish titanium was still used as the mac notebook enclosures. I don't mind minor cosmetic anomalies that occour over time so long as the portable is built like a tank. I have has a G4 aluminum powerbook since they came out and the case still looks new. The finish is very durable. I just upgraded to a macbook pro. I look forward to a long life from it as well. Just my 2 bits.

Dave F