Questions about expansion & contraction
I am building a table that will be outdoors. It's made of cypress. The top will be attached to aprons using figure 8 clips to allow it to expand and contract as needed. There is also a lower shelf that will be attached the same way, but expansion of the shelf will be limited by the table legs on each corner. The shelf will be 22 inches wide, made of edge-joined cypress boards. I need to leave gaps around the legs but I am not sure how much expansion to expect. Any idea how big the gaps should be?
As part of the same table I am building a circular pedestal, also from cypress. I plan to start with a 16-sided polygon made by gluing 3.75 inch wide boards together, then rounding it. The end result will be a circular pedestal about 4 or 5 inches tall. Again my concern is about expansion. If I construct the pedestal with the grain running up and down, won't it expand/contract across the grain and tend to tear itself apart? If I orient the grain side to side the glue joints will be on end grain, which doesn't seem like a good idea.