<VV> casting aluminum

[Ron]

John, you're being realistic!  There's no place for that on this list.
RonH

----- Original Message ----- 
From: "John Kepler" <jekepler at amplex.net>
To: <JVHRoberts at aol.com>; <sarge9444 at yahoo.com>; <virtualvairs at corvair.org>
Sent: Monday, August 06, 2007 4:46 AM
Subject: RE: <VV> casting aluminum


>
>
> Bottom line, if you were to do this, you would have them cast by a casting
> house.They know all these details.
>
> Just to inject a touch of economic reality into this, and explain a couple
> of problems with all of this talk of casting a fan.
>
> First, a fan impeller is NOT a type of investment casting that is going to
> be easy to make....the low mass requires VERY thin web-thicknesses, as 
> well
> as extreme dimensional consistency.  These requirements will generate high
> reject rates, which will raise cost considerably.  Second, the low-volumes
> for an aftermarket part will force anyone contemplating this into the 
> realm
> of the "Low-Volume Job-Caster".....the bottom-feeders of the metal
> fabrication world!  These guys are great for making belt-buckles and cute
> little yard ornaments....but not so good for a critical 
> high-speed/high-load
> automotive part that will require precise alloy integrity (which also
> implies things like engineering and laboratory support that they usually
> don't have!), as well as some pretty good equipment and a high-degree of
> casting expertise that is HIGHLY uncommon in that group of firms (I'm 
> being
> generous....I've never found ANY low-volume job-caster that could make a
> consistently decent product, but I suppose there HAS to be one out there!)
>
> At the end of the day, and in the volumes that are reasonable to
> expect.....it'll be easier and cheaper to CNC mill the fan out of billet
> than cast it, with one hell of a lot better fan out the door!
>
> John
>
>
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