Aloha Patrick All 5 piers that I have constructed are from welded steel tubing (4-8",1-6") with a base plate of 3/8" to 1/2" plate steel w/ a 22" diameter to which 1/4" to 1/2" wall 8" tubing is welded w/ 3 to 6 gussets each. Three leveling holes are made (spaced 120ยบ apart, 1 1/2" in from the edge) thru which are 3/4" threaded rods cemented into the pad. A pair of 3/4" nuts one each above and below the base plate serve to get a level top. The tops are usually machined 1" steel plate so a groove beneath the top cap fits over the pier tube, holes drilled in the top cap anchor the cap to the tube. We've been filling our piers at the Haleakala site w/ sand, used lead tire weights and iron window weights. After final assembly, I'll have the piers sand blasted, primed and painted. My first pier painted 22 years ago is just beginning to show rusting but that's from 4 moves and it is exposed to the mountain elements. I hope this helps, a hui ho Rob http://gallery.utahastronomy.com/main.php?g2_itemId=5914 http://gallery.utahastronomy.com/main.php?g2_itemId=5911