joining fiberglass?

[Gary Dillard]

just a quick safety reminder - even though the extruded fiberglass looks and feels pretty solid, it's still fiberglass. If you cut it and/or drill it, you expose a bunch of tiny glass fibers that hurt and itch like heck if (when) they get on your skin, especially your fingers. Be sure to seal them up good and use gloves when handling.

Also, engineering wise remember that the elastic modulus of fiberglass is on the order of 100-300 ksi versus aluminum which is 10 Mpsi, so check your deflections if it's going to be highly statically loaded. Conversely, this makes it better than aluminum for absorbing shock coming from "rigorous interaction with other robots" (except a direct hit since it's more brittle) since the spring rate is much lower.

[falconmaster]

We over come these issues by using 1/4 inch thick fiberglass extrusions, its more weight but a whole heck of a lot stronger. Just try and break it!

[Gdeaver]

Yes, using 1/4" wall will yield an arm more than strong enough for the tetras and rough play. However the weight penalty and the effects on cg are not good. 1/8" wall is much lighter. If the ends are reinforced with tube in tube you can have almost the same strength with a weight savings. Think double butted tubing.