Obviously with a trick. Look at the photos, you will see the aluminum and the stainless steel bowl. It's easy, I will wrap around the hole a copper foil (the same used in stained glass) and the same around the bowl, then I can easily tin weld. Nex time I will show how to do with photos. P.S. I've used very good nips to cut the aluminum, see photo
Thank You, Ted. This metal story is my Christmas gift to all of you. If you look back the photos, there is one of a first attempt tha I've left down. Tecnically correct, but estetically not. Then I've studied the problem as an artist, I remembered things as "golden section" and all they make in the Liberty architectural/artist period. They refere to Mother Nature. It was an illumination, I make it in a hurry, and I'm shure that if everybody in this world can live in accord with Nature things will be better. Flower power ! :-) Merry Christmas and happy new year !