Islamic coins: Sand casting

Figure3.18 - Adams, Z., (2019). Zikr Umla. Brass and copper sand cast coins.

For the technique of sand-casting, I made multiple coins in brass, copper and gilding metal. Sand-casting is a type of casting I had not tried before, but hearing about the process and outcome made me curious to try it. I thought that the mold, being made of sand, would leave a sand-like texture to the surface of the object that is cast, which I would like to see on the coins.

Sand casting is quite a quick but messy process, considering that from start to finish, one could cast an object in under an hour. For sand casting, I used the following items: Casting sand, a two-part aluminum flask, a wooden dowel, a cement scraper, a 7mm drill bit, and a board to work on (see figure 3.19). The method of sand casting essentially involves creating a mold of your piece in casting sand that is well compressed by packing it using the wooden dowel, then creating a channel with the drill bit for the metal to flow to the piece and then proceeding to cast.

Figure 3.19 - Adams, Z., (2019). Sand casting equipment.

The result was beautiful. I was very happy with the way the coins had cast. The coins have the effect I was trying to achieve which is to look old and slightly damaged because of years of use. Some coins did not cast fully, because my metal was not melted correctly. These coins I found even more interesting because they look like very old coins that have pieces broken off. One word I could use to describe these and the other sand-cast coins is "relic".

Islamic coins - etching technique

Figure 3.16 - Adams, Z., (2019). Acid etching copper coin

The method of acid etching begins with using heat to transfer a resist (printed out on plastic sheet) onto copper plate and placing it into ferric chloride for a few about 3 hours, depending on how deep you want the etch to be. Figure 3.16 shows the copper plate that has the coin design printed (resist) on and is ready for etching.

The etched prototype proved not so successful because the coin did not etch deep enough, but I also did not like the look of the etched metal background of the coin. The background was very uneven and bumpy, which I felt took a lot of attention rather than the words. So I will move on to the next method; piercing and soldering.