How do you think it improves the realism of your model? I think it would be a very unpractical material to model with.

Aluminium (aluminum in US English) a fairly good, though now old-fashioned, material for casting whole models (travel agent style: see for instance Verkuyl [exeunt] in the Netherlands), though I doubt if it can be used to cast practical kits of small parts for making models. Bear in mind that aluminium on its own would corrode and lose its appearance rapidly. Perhaps you mean expensive indistrial grade aluminium alloys (duralumin, etc) as used in airframing; these are also prone to corrosion, while also raising significant poisoning issues (alongside 'pure' aluminium).

To make parts from _thin_ aluminium (as you suggest in your post), one would need to invent a new process or adapt the car inductry (VW/Audi and others) process of die-stamping aluminium sheet using very costly tooling. One would then end up with what looks like a vacuum-formed aluminium part which would need to be trimmed off the stamped sheet using yet another very expensive set of trimming tools. How the modeller would go about assembling and gluing aluminium parts is another area for enquiry -- most likely, using superglue, having to remove its excess using files, and having to somehow refinish file-scored areas...

"White metal" -- in fact, a large group of soft metal alloys, mostly of proprietory brands specifically made for modelling -- is regularly used in aftermarket aircraft kits (typically, landing gear). The multiplication process is called "centrifugal casting" and employs simple centrifuges costing perhaps 1000 euro and expensive latex or synthetic rubber moulds which last for up to several hundred "shots." (It is also possible to multiply prototypes in small numbers at home artisanally, relying on gravity and sundry cast-off domestic vessels, again using rubber moulds.)

Somewhat harder versions of essentially similar "white metal" alloys are the mainstream material for casting entire kits of intricate parts for car modelling. The multiplication process is called "die-casting" and is quite similar to injection-moulding; molten metal (instead of molten plastic) is injected under pressure into expensive tools ("tools" or "tooling" are the correct terms here; not "moulds" ["molds" in US English]). (Many, many car model kits are made using the cheaper centrifugal casting or even cheaper gravity casting processes, however.)

A look at the typical self-assembly 1/43 car model kit would convince you that the appearance of the metal used is nowhere near that needed for the bare metal finishes to which aircraft modellers aspire. I am unfamiliar with the techniques one would employ to achieve a good metal finish on white metal, except to say that it would certainly tarnish quite rapidly and require refinishing. Tarnish ("patina") appears readily on white metal surfaces exposed to air and deepens with time. Mechanical intervention (sanding, polishing) often tends to increase the surface area exposed to air and hence to boost the propensity to patination, ending in a vicious circle.

It seems to me that established plastic modelling techniques such as applying kitchen foil (_there_ is your thin aluminium sheet!) or good quality paints over plastic already produce more than acceptable bere metal appearances, but this is naturally subjective.

Interestingly, a self-assembly model kit of an airliner (the Vickers VC10, as I recall) was announced for imminent release about ten years ago on the Airlinermodelling Yahoo Groups forum but sadly failed to materialise. Ironically, the VC10 was never flown in any bare metal colour schemes since its manufacturers insisted on all interior and exterior metal being thoroughly covered with a characteristically coloured beige-grey primer.

I can only surmise that the would-be-maker of the abortive VC10 might well have found white metal casting to be economically (rather than aesthetically) preferable to other "garage manufacturing" methods. If so, s/he was certainly right, for gravity and centrifugal casting come second-cheapest to vacuum forming, while white metal is cheaper than casting resins.

In addition, white metal is significantly easier to "cook" at home or in a garage setup than resin. It is also probably "friendlier" in terms of chemical emissions. As opposed to resins, it has an unlimited shelf life, removing the damage risk factor from storing it in less-than-ideal conditions or for extended periods.

So, while your idea might not be a winner in terms of bare metal appeal, it might be quite attractive in terms of cost. Provided, that is, you go for casting white metal rather than aluminium...

That's a M O D E L ? Wow!

(... turns and goes away to take holy orders)

I've seen photos of the two models that the Japanese guy built. they are large scale and took him a very long time to complete. I've actually thought about building a very big DC-7 that way, but I don't wish to spend the rest of my life building just one model! However, I do make some of the parts on my small kits out of aluminum or some alloy of it. Parts such as the gear doors so that I can get a nice thin, sharp edge. A good source for thin aluminum is Pizza Hut carry out food that is in a metal container. Those containers are thinner than what you can buy in the grocery store. After I delight in eating the pasta, I then wash the tin and rough it up with sand paper on one side. I then take the plastic gear door and sand it down and reduce it a tad. Then I super glue an oversize piece of the aluminum tin. After it's dry, I cut around the outline with a pair of siccors, leaving just a RCH of overlap. It gives a great realistic look not only for its aluminum look, but also the clean, thin overlap around the edge.