allaboutcircuits.com - Is the surface of water ever “perfectly” flat?
Except for surface tension at the edges and with no motion, the surface should be almost flat.
Other liquids such as molten tin exhibit near flatness and the surface can be used as a reference and also a mold for casting other flat shapes. s an example, plate glass is made by applying molten glass over the surface of molten tin.
wikipedia.org - Float Glass
Float glass is a sheet of glass made by floating molten glass on a bed of molten metal, typically tin, although lead and various low melting point alloys were used in the past. This method gives the sheet uniform thickness and very flat surfaces. Modern windows are made from float glass. Most float glass is soda-lime glass, but relatively minor quantities of specialty borosilicate and flat panel display glass are also produced using the float glass process. The float glass process is also known as the Pilkington process, named after the British glass manufacturer Pilkington, which pioneered the technique (invented by Sir Alastair Pilkington) in the 1950s.
As of 2009, the world float glass market, not including China and Russia, is dominated by the four companies: Asahi Glass, NSG/Pilkington, Saint-Gobain, and Guardian Industries. Other companies include Sise Cam AS, PPG, Central Glass, Hankuk (HanGlas), Zeledyne, and Cardinal Glass Industries.
instructables.com - Cast Tin
I got an order for some tin cubes. I found that there wasn’t an instructable for casting tin, so I recorded my steps and went through it for you all to see.
Why tin? Tin melts very low in temperature. Basically, the lowest melting point of any useful, non-toxic metal(*). It melts around 500 degrees, is very castable, and looks brilliant. There’s only one real good reason not to use it: it’s relatively expensive. I got mine from Rotometals in San Leandro for around $10/lb. Its density is similar to lead.
mrhomescientist - Metal Bars: Casting
youtube mrhomescientist - Metal Bars: Casting
JoergSprave - Cast Metal Slingshots
youtube Cast Metal Slingshots: The Sheffield Secrets Unveiled!