In many situations, you CAN properly (and sturdily) join two lengths of PVC pipe! (What ever you do, do NOT use the couplers normally sold to join two pieces of PVC pipe, they are NOT mechanically strong, and just plain won't work in this situation.) You need a 3-4' length of pipe of (usually) one size LARGER than your mast portions, and split it lengthwise. (A table saw used judiciously comes in handy, but you may be able to get away with using a hacksaw. Be CAREFUL, either way.) There should be a tight fit once the pipe is split. Using (at least 3-4) hose clamps to close the split pipe,. insert both pieces of mast into this coupling equally, and tighten the hose clamps! Works and lasts as long as the PVC masts last, which is 20+ years (and counting.) Of course, guying IS required.