Lost Wax / Investment Casting and its history

[timmy]

I've always been intrigued by the modern investment casting practice that is used for making parts of cast alloy steel.

The benefits and economy of being able to obtain strong alloy parts by casting them to a shape that is, to some degree, the approximate shape of the finished product, compared to machining that same part out of a bar of steel is immediately evident. If you examine a gun made by Ruger (which I'm familiar with), you'll see that much of the investment casting is so accurate that it is left unfinished, other than blueing. Only the outside surfaces, for instance, of my Blackhawk are polished. Inside the frame where the cylinder mounts, the surfaces are blued as cast. Compared to machining the whole frame out of a chunk of steel, there must be a considerable cost savings!

In our modern world, our focus is often on the immediate and it is easily forgotten that our knowledge is built upon that of the past. The following is a summary of what I find interesting about investment casting:

Lost Wax Casting

Investment Casting

Specifically, please compare the similarity between the two methods and also the history this method of metal working has in South Asia.

Since a picture is worth a thousand words, here is a pretty good (and scholarly) video I found on Youtube that brings the whole thing home very well:

[youtube][/youtube]
Imagecasting in Swamimalai, southern India

Please excuse me, I'm sure that most (if not all) of this is "old hat" to you all, but I just find this stuff fascinating. Thinking about how these most ancient processes were developed, and how they relate to our modern lives so closely, including (and especially!) our shared love of firearms, is something I just can't quite get over marveling about.