BAMS – Medal project – PatinatingPosted: June 3, 2015
The final step in finishing my medals is to patina them, in order to make the fingers and imprints distinctive from the surface of the medal and to show the touch pattern on top of the fingers through polish.
The first step is to heat up the medals using the blow torch, making sure to turn it so that the heat spreads evenly and keeping in mind that the thinner areas will heat faster. The bronze should be hot, but it is important not to heat it too much otherwise the surface can burn, which is the last thing we want.
Then it’s a matter of spraying on the patina, which is essentially just a specific acid, onto the surface of the bronze. It should be hot enough that the patina sizzles when it hits the surface.
Keep repeating this process of heating and spraying until the surface is evenly covered and the colour you want it
Running them under cold water allowed me to clean them up, and as far as I’m aware is also important in setting the patina. However I was surprised at just how easily I could rub the patina off the surface of the medal with just a rag and water. I’m not sure whether or not this is a matter of me not having heated the bronze up enough when applying the patina, or simply just the way in which the patina works, but in attempting to remove some of the excess which was blocking out the detail of the cast skin, I found the majority of the patina came away with ease.
It seems as if the patina especially struggled to stick to the surface of the nails, which are smooth, and this came off without me even directly trying to clean them. However I took advantage of this quality and cleaned the surfaces of the medal with a wet rag, leaving the edges and indents patinated.
After doing some more rigorous polishing and cleaning, this is the result. I also attempted to polish into the areas of the fingers reflecting the pattern of the imprint on the back, as represented in my sketches, but I found that the markings were extremely indistinct. I think this is largely due to the amount of patina which was inadvertently cleaned off of the fingers, leaving some areas already looking relatively polished where they should not be, making it unclear that only a specific pattern of areas should be polished on the fingers. As well as this, there are areas on the edge of the medal which are blotchy or where the patina has rubbed off, again making it not distinctly a different colour from the polished surfaces on the front and back. I think the answer to this is to patinate them a second time, which I aim to do tomorrow. I would have done this today, but unfortunately the technician had locked away the acid before he left reasonably early in the day, but there should be time to do this.