The use of fiberglass for the manufacture of collinear УSW antennas and struts "squares" is a common phenomenon. Often for these purposes a fishing rod, which at the end of the season are not that expensive compared to aluminum pipes (non-ferrous metal!). In addition, the rods have a good "story" from the perspective of the mechanics of bending, since, in addition to the telescoping, there is also a slight taper.
I suggest (maybe my idea and not the original) to use them as bearing elements for SW-type antennas Yagi. Within these fiberglass tubes should be placed duralumin (copper) wire, which, in fact, shoulder vibrator, Director or reflector. Because the conductive element is thin, it is necessary length will be close to the calculated one. In addition, significantly reduced the impact of the boom and the need to introduce amendments to its effect, since the elements are isolated.
At a reasonable observation Victor Pronin (UA4HBW), the latter allows less problematic to implement and antenna type LOG-YAGI, where it is necessary to isolate the elements from the boom. The antenna elements are protected from the weather. The antenna tuning can be carried out using ordinary pliers simple nibbles wire.
To reduce the influence on the parameters of the antenna dielectric (GRP) and eliminate mechanical rattling, vibrators in several places recorded in tubes of foam rubber "washers" (pieces of foam) - as in the collinear antennas. The antenna produces a light and durable and does not require additional wires from the side of the boom, which, as a rule, it is necessary to break isolators (bend, but not break). Becomes simpler implementation of the antenna type Yagi on 40-and 80-meter band (there are long rods!).
Of course, in an industrial environment the design of the tubes may be specially designed.
Literature
Publication: N. Bolshakov, rf.atnn.ru