Tina and I were asked to make copper chisels for a television show about Ancient Egypt (here is the show; oddly, I haven't seen it yet so I don't know where the chisels play. We also built a lot of the sets and props for the reenactment parts and the Pharaoh statue was molded off my mug!!! :). The premise was that they wanted to test to see if pure copper (very soft) chisels could chip away at granite. Our good friend Steve at Bazay Blacksmithing helped us out. We spent an evening at his smithy and poured molten copper into ingots and then hammered them out into the shape of chisels. They tried the chisels out and it turns out that you CAN split rocks with them (they just have to be re-sharpened often!!). I'm going to plagiarize some tech spec info from Wikipedia to help explain the science behind the processes.

Also - I'm entering this in the INDESTRUCTIBLES contest, if you like it please vote and I will appreciate it muchly (I'm after that silver sparkly motorcycle helmet!!!!!!)! I figure we're still finding tools the ancient Egyptians made (pretty indestructible stuff there, fellas) and I'm hoping my chisels will also be found thousands of years from now (and some archaeologist will try to figure out why and how they were used... :)

Step 1: Melt your copper

IMAGE 1: This is the crucible sitting in a bed of coal in the forge. It has to be hot enough to melt pieces of scrap copper that we collected. Copper melts at 1083 degrees Celsius, 1981 degrees Fahrenheit.

IMAGE 2: Here are three pour spouts (or cavities) that we've set into the sand. The cavity in the sand is formed by using a pattern (an approximate duplicate of the real part, or, in this case, three pipes that are slightly larger than the chisels). The cavity is contained in an aggregate housed in a box called the flask. Core is a sand shape inserted into the mold to produce the internal features of the part such as holes or internal passages. Cores are placed in the cavity to form holes of the desired shapes. Core print is the region added to the pattern, core, or mold that is used to locate and support the core within the mold. A riser is an extra void created in the mold to contain excessive molten material. The purpose of this is feed the molten metal to the mold cavity as the molten metal solidifies and shrinks, and thereby prevents voids in the main casting.

IMAGE 3: The crucible has finally reached a temperature hot enough to start putting bits of copper pipe into. As it melts and puddles at the bottom of the crucible it becomes easier to add more copper; the new additions begin to melt almost instantly.

IMAGE 4: Copper is notorious for popping; it is highly susceptible to any moisture in the air can add hydrogen to the molten copper. Copper should be melted under a floating flux cover to prevent both oxidation and the pickup of hydrogen from moisture in the atmosphere. In the case of copper, crushed graphite should cover the melt. Pure copper is extremely difficult to cast as well as being prone to surface cracking, porosity problems, and to the formation of internal cavities. The casting characteristics of copper can be improved by the addition of small amounts of elements including beryllium, silicon, nickel, tin, zinc, chromium and silver.IMAGE 1
Good Job! The photos you put were beautiful! You know how its done! :)
Were you guys pouring that molten metal on a concrete floor? I was under the impression that was a big no-no since the moisture in the concrete turning to steam could possibly cause an explosion resulting in fragment and hot molten bits flying about.
Good eye! No, the actual pour was on top of the welding table, directly into the sand cast mold. The remainder in the crucible was poured into an ingot box that WAS on the floor, to be saved for later pours. If you look at the first batch of photos you'll see a volcanic spatter of molten copper; a small tap on the surface of the crucible was enough to make it react like that (moisture in the air plus the pressure of trying to shove more copper pipe into the crucible).<br> <strong><a href="http://darwinawards.com/stupid/stupid2008-01.html" rel="nofollow">Here's</a></strong> an unrelated but amusing story of the dangers of molten copper.
Come on, let's see the rocks being split!
I haven't seen the show yet, I was told afterwards that the chisels worked. It's funny, T and I build quite a number of props for shows that we never end up seeing. I always thought it was weird when I heard that Harrison Ford had never seen the Indiana Jones movies until I started working in this business; you just get really busy and then don't end up seeing the shows. I hear it's pretty common for people that work in the industry...?!
OK - maybe add a YouTube clip when you can? <br> <br>I recall reading some time ago that Egyptian masons worked with teams of metal workers who maintained batches of chisels, sharpening the ones that the mason wasn't using.
OK you made copper chisels that could split rock but could the Egyptians have? They did not have steel tools to work their copper with. If they did they wouldn't have been fooling around with copper chisels.

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Bio: My girlfriend and I run a company called Deville's Workshop in Toronto, Canada. We build weird props for film and television and love this ... More »
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