Shawn's Design.... this will be her project to learn these processes.

This was a two day workshop. Very labor intensive and challenging. To learn process you need a good project and Shawn McCurdy had a few different ideas that appealed to her. I always encourage each participant to draw the designs with as much detail as possible. We decided on a great rendering that she had for a birdbath. Something that I thought would be achievable in a two day workshop.  
 

The first order of business was to cut the top basin and the base out of 3/16" aluminum sheet using the plasma cutter. The top basin is 22" square and the base is 18" square.

We annealed the pieces with the OA torch, using the "paint stick" method of determining heat, then cooled them with the hose. While annealing, the pieces were suspended between 2 supports and they slumped or warped downward, which gave me some shape for free!

Originally we had planned to use the treadle hammer to shape the base and top. However, we quickly decided that a smooth surface would look a lot better so I dished them entirely by hand, using a wooden support and dead blow hammer. My arm is sore.

The supports were made from flat bar stock (1.5" by 1/4" I think). I sketched out a representation of my design and we measured the length of a representative leg, which turned out to be about 4.5'. After cutting the bar to that length and shaping each end to a point with the bandsaw, the first thing to do was texture the whole piece using fullering dies in the power hammer. It makes easy work of this!

 

Next the top end was bent into a support for the basin and the bottom end into a support to attach to the base. Then the in between part was bent and curved by stretching various sides on the power hammer. (Did I say I liked the power hammer!) Repeat for three more legs.

Assembly was the tough part. The supports all had to be the same height. Tweaking the height was easy enough by putting more or less bend into a piece, but that usually threw off the position of the top or bottom horizontal end...eventually we got it close and, starting from the bottom, welded it up. Wherever legs touched they were tacked together to help stiffen the whole thing.

Once we got all four legs put together with the base and basin, we decided that it needed an extra piece, both to fill in some of the negative space in the center plus to tie the legs together in a few more places.


 

So I made a spiral-y piece out of a short length of aluminum bar that was left over, and we fitted it into the mid-section of the legs.

What's left to do? I need to go over the entire surface with a scotchbrite pad and polish out some scratches. Then I'll clear coat it, at least on the outside. I'm not sure how Permalac reacts to immersion in water - anyone? I'm thinking now that I'll leave the inside of the basin uncoated and just wax it good.
Here's Shawn McCurdy and her finished aluminum bird bath.

This project would not only let Shawn anneal and dish some sheet aluminum, to make the base and the bowl. But also, do some forging of some aluminum bar stock, for the decorative vertical elements that support the bowl. And once all the elements were made...It left a challenging fabrication phase. Challenging because the forged elements were very "free form and organic", which really complicates the fabrication of a piece like this. This was all part of the plan.