<BLOCKQUOTE><font size="1" face="Verdana, Arial">quote:</font><HR>Originally posted by Size15s:
Wow! Thanks for explaining things. I guess I assumed too much.
Would the Anodisation you desribe be like the "Type II" - because normally, they are 'glossy' which I thought was 'sealed'
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Al<HR></BLOCKQUOTE>
OK, I did a bunch of double checking - The "standard" anodize that I describe is Type I if you don't dye it, and type II if you do. It seems that Type III isn't so much a different "bath" (My mistake), but it's done at a much higher current density
As for which temper is best? First you have do define the alloy, then the temper. This is where the designers make their money - what is the BEST alloy for the job, and then th best temper.
Some of the factors involved are:
Strength, weldability, machineability, can ithe alloy be anodized, cost, intended use, etc. For instance 2024 is just about the most machineable alloy out there - you can run your lathe/mill much faster then if you were running, say 7075 at the same temper. The thing is, it's not as strong. It's all tradeoffs
here is a page that will give you some idea
http://www.principalmetals.com/properties/step1.asp
LOOK at how many different KINDS of Al are there (They list 46 different kinds of Al, not counting tempers).
Which alloy is best? You tell me! (I'm not kidding)