working small, working in the negative, a tutorial

I often have to work quite small, with geometric shapes. If I'm to do this cheaply, I'll do it by hand, if possible. I worked for decades before CAD and CNC, so this is a trick learned over some time.

This custom hardware was commissioned by a homeowner who was building an elaborate wine cellar. These were his own bronze door latch and hinge elements. I got started in wood and wax, roughing in the details. Then I took carveable plastic moulds and carved them, in the negative. Here's the final casting:

Bronze door hardware cast in lost wax at Artcast in Georgetown, Ontario.

Here is a series of renderings that show the steps taken to get this fine detail that 'pops' off the surface.

I started with the shape of the final object and took a mould off it in plastic (fast-cast polyurethane, fairly carveable):

Then I put a small round cutter in my Dremel and cut little half-round holes into the surface of the plastic to form the grapes:

I press clay into the surface to check my shape, refining as I go. I carved stems and other lines at the same time.  When I was happy, I waxed the surface to release the final plastic copy. I mixed more plastic and poured it into the cavity, and here's what I got:

The dark blue is the final plastic copy from the intermediate plastic mould that I was carving.

I'm often done at this point, though I can continue carving into the new surface to refine detail if necessary.

Cool, huh? Thinking negatively is good sometimes...