Recast Question

Just out of curiosity...why are recast parts rough and gray in color compared to original cast parts? The original cast parts on my G109 are black and smooth. I'm sure the dark color comes from years of polish, but why are they much smoother than the new recast parts?

tcalo wrote:Just out of curiosity...why are recast parts rough and gray in color compared to original cast parts? The original cast parts on my G109 are black and smooth. I'm sure the dark color comes from years of polish, but why are they much smoother than the new recast parts?

No matter how smooth the pattern piece is, the molds used for casting are made of fine sand mixed with a special oil, or water and clay for finer finish to help bind it together. The finer the sand, the smoother the parts will be. But the castings (new and recast) will always show some amount of sand-gain texture.

The smooth cast parts are made by lost wax, or die-cast processes, which are much more expensive, so they are typically only used in art work and high-value parts (lost wax), or mass production of tens of thousands of parts - die cast. Die cast (aka zinc die-cast) used to be also called the 100,000 part method because of such high parts volume needed to pay off the very expensive metal molds used.

To answer the smooth parts, part. The big stove factories not only had their own foundry, they also had parts finishing departments too. There the cast parts were ground and sanded smooth, all machining, holes drilled, etc, before going on to the final assembly section.

Paul

Thanks for the explanation SB, I now feel smarter...