Re: How good would Aluminum armor be?
 

I know that helmets made from aluminum make you immune to mind control, especially if they are pyramid shaped.

Re: How good would Aluminum armor be?
 

At least that's what they want you to believe.

Re: How good would Aluminum armor be?
 

Indeed. Aluminium blocks proper orgone flow.

Re: How good would Aluminum armor be?
 

I use 3/16" 6061 T6 aluminum for my SCA armor. It deals with rattan bludgeoning weapons nicely. Maybe not against a flanged mace or something like that, but it would give some DR... 2 or 3 seems reasonable.

Re: How good would Aluminum armor be?
 

I believe you mean tin foil hats. Making people mistake tin for aluminum so often people assume you mean the second when you say the first is all a part of "their" plan.

Re: How good would Aluminum armor be?
 

Aluminum armor in the field has turned out to be not-a-good-idea since 1965. It fragments a lot worse than steel, so a small hole becomes a small hole plus a lot of shrapnel. It also has a marvelous tendency to catch fire. I was in a squadron that had a plane deployed on a carrier in the Med when the Belknap caught fire. It had a mostly-aluminum superstructure. It burned so hot that our guys on the carrier almost got cooked just being close to it!

Re: How good would Aluminum armor be?
 

Nah, it's just old technology. Mind control rays used to use aluminum optics - the famous aluminum pyramid at the top of the Washington Monument for example. Governments haven't used this system since they started deploying mind control satellites in the 1930s, but there are still corporate users. I think the parabolic shape on the bottom of aluminium beer or soft drink cans are focusing elements to concentrate them on your head as you drink from the can.

Re: How good would Aluminum armor be?
 

They let that rumor escape. By tricking you into switching to glass bottles, you have less aluminum handy, not to mention eliminating the beer coozy hat. And you notice there's a parallel rumor that says your beer bottles ought to be brown instead of clear, purportedly to protect the beer. There's a reason they don't want you to be able to see inside of them.

Meanwhile, back on topic, what property is used to evaluate DR for a material? The "aluminum is 1/3 steel" makes me think modulus of elasticity? There are aluminum alloys which can get about as hard as steel.

Re: How good would Aluminum armor be?
 

Which can actually save even more weight over steel. Since aluminum armor of a given weight is thicker and more rigid, aluminum vehicles pass from "frame with armor bolted on" to "vehicle shaped shell" sooner. A steel M113 would have required more extensive internal structure.

Aluminum still has plenty of problems, of course. Probably chief of which is that it burns. Look up USS Belknap for a good example (short version: aluminum superstructure completely destroyed, steel hull in need of new paint).

Re: How good would Aluminum armor be?
 

Apparently the problem is that aluminium collapses under a lower temperature than steel, not that it burns better than steel. It does conduct heat a lot better which can be a problem on ships. Aluminium suffers more from metal fatigue than steel.