Hi Richard

If you can get some Cypress lumber to make your boom, it will last
longer than you do!

We had 12 acres under glass, all of the greenhouses were made from
Cypress rails which held the glass in place. They were 71 years old
when we sold the place to a shopping mall developer.

These rails were only 2x2s with two dado's cut out for the glass and a
decorative slot cut down each of the inside portions. They held the
weight of glass just fine for all those years.

TTUL
Gary