Copper Bowl II: Raising Technique

In our second project we started with a copper plate of the same diameter that was used for the first bowl. The raising technique compresses the copper and thickens the wall. The shape created above was made by hammering the outside of the bowl against a rounded T-stake (as opposed to hammering the inside of the bowl against a concave groove using the sinking techique). I'm finding that raising the bowl is a much slower and tiring process than sinking.  The technique is generally needed to create certain designs that can not be formed by sinking alone (or so I've been told).



Here is the bowl after another four hours of hammering and annealing. Raising is definitely more tiring than sinking. It's starting to look more like a bowl now.

 


Three final hours of hammering and the bowl is pretty much complete.



 

Here are photos of the two bowls together. The diameter of the first bowl using the sinking technique is 5.25 inches while the diameter of the second bowl using the raising technique is an inch smaller. I thought the difference would be a bit more dramatic but perhaps that's only the case when the instructor does it properly!

Left bowl formed by sinking, right bowl formed by raising

Copper Bowl I: Sinking Technique

In this Silversmith course we are working exclusively with copper (go figure). At George Brown silversmithing refers to the techniques used in creating larger pieces of silver items such as plates, bowls, spoons, tea sets, etc. These techniques involve primarily different ways of hammering the metal to form it into your chosen design. The types of jewellery formed by this silversmith method are very different from what I had created in my "Silversmith" classes at The Devil's Workshop. I'd actually equate those techniques with George Brown's goldsmithing classes (where so far we are working with brass and silver!). Anyway terminology aside here are some of the projects from my Silversmith course at George Brown.

Creating the initial bowl shape out of a copper disk

In our first project we created a bowl out of a sheet of copper by purely hammering techniques. The method of sinking stretches out the metal and thin the walls. I started by drawing concentric circles on the copper plate and hammering the bowl over a small concave groove (much smaller in diameter than the bowl) to slowly bring up the sides of the bowl. In between hammering I had to frequently anneal the copper because it hardened with every blow.

Checking the shape against my template

  After achieving the general shape I created a template of the bowl by tracing out half of the circumference at the mouth and used that to guide how deep the bowl would become. The goal was to create a hemisphere. In the second week I worked from the outside of the bowl (you can see the grid marks I drew in the photo below) and used a hammer to shape the bowl against a convex stake. This technique finishes both the inside and outside surfaces of the bowl simultaneously while shaping the bowl to the template.

Almost there, I'd say

The bowl will be marked against it's template to see how close it is to a perfect hemisphere. After marking we will be free to change the design of the bowl by cutting an interesting edge out of the top, hammering designs into the walls of the bowl, or creating feet at the bottom for the bowl to stand on. There were some pretty cool designs on display in the classroom so I'll take a closer look next time.