The stuff I can get from my local wholesaler is IMC. Intermediate Conduit. They said they do not have a listing for rigid spec aluminum. Spec sheet lists O.D. at 1.638 and Wall thickness at .095. Much thinner than schedule 40. That being said I am interested to see how it would perform in an all welded frame with no clamped/set screw fittings. It would most likely be stronger than Schedule 40 1" but might not be much cheaper. I would have to buy 5 sticks minimum to get it. 100$ isn't a huge gamble but would suck if it didn't work out. Will keep looking to see if I can get rigid aluminum conduit around here. I would say build it with what you have, Curtis, and thanks for the info.