Sheet Metal

As I explained in an earlier blog, it’s hard to get Rob to my garage, so I’ve been making bucks and bringing those to Rob, who then makes the sheet metal to fit the buck. In this case I also made a paper template that I stretched over the buck. It’s another representation of the sheet metal, and a way to tell where the heavy duty stretching and shaping will be.

Rob used the paper template to mark the sheet metal and then cut it out.

When we started the project, Rob explained that there are 2 ways to do this: create the flanges at the edges first and then create the dome in the center, or create the dome and then the flanges. Rob chose option number one, the nearby photos show how he started with a flat piece of 18 gauge steel and ended with a complex piece of sheet metal - what’s essentially a partial dome with two reverse flanges.

Rob starts the shaping with nothing more complex than two strong arms and the edge of the table.

This is the first check of our progress.

The crown that runs through the center of the piece is done with the English wheel.

The crown is subtle, but important, and easier to see with a straight edge.

The flanging comes last, most of it is done with the plastic hammer and a home-made T-dolly.

The buck is obviously too flimsy to shape anything over and is only used to check the shape, which is pretty close at this point.

The nearly finished piece set in place – better than a painting by Picasso any day.