Today's puttering involves determining how I am going to attach the three 11 foot long, 10 gauge posts into one 33' long segment. This will form the backbone of the mast and will support the rotator and thrust bearing brackets. The pipes have an OD of 2.375" (60.33mm) and an ID of about 2.115" (53.73mm). I want to use a two foot section of aluminum pipe (for weight savings, maybe 0.5" thick wall) at each of the two joints such that there is one foot above and one foot below the junction point. One grade 5, 7/16" bolt will be used at the top and bottom of the joint to connect the mast pipe and inner pipe sleeve together (like I did on my current mast). The closest aluminum pipe I have found to the 53.75mm diameter that would work best for the inner pipe has an OD of 2" (50.8mm). This would leave a bit of slop around the junction pipes. I could possibly find someone with a TIG welder to weld a half-dozen or so filler strips on each of the two sleeves to remove the slack. I also read somewhere else that said just to fill the gap with duct tape. I'm not going to over-engineer this and spend way, way too much money on it for the outcome I expect.