joining fiberglass?

[RBrandy]

Team 93 used fiber glass impregnated plastic last year on our upper frame. It worked out really well, only one piece of it ever broke. To attach it to other members, we milled down a piece of structural aluminum to a press fit inside the fiber glass and tapped the hole of the aluminum.

If you have any more questions about out technique, feel free to e-mail me: ryan.brandenburg@gmail.com.

GOOD LUCK

-Ryan

[falconmaster]

We built our entire robot out of extruded fiberglass from Creativepultrusions.com. They have angle and tube, c-channel and I-beams etc... You can use lock nuts, washers and bolts and even bolts that can be counter sunk if your fiberglass is thick enough. Fiberglass kits from Home Depot work great too, just scuff up the surfaces you want to fiberglass together. The kit comes with the resin, hardner and some kind of nylon cheese cloth. Attach the cloth around the joint and fiberglass away.
If you need any help....coachfredi@hotmail.com 602-764-3000 ext 60233
Ask for Fredi Lajvardi

Also checkout Creativepultrusions.com and contact them if you want expert Help!!!!! Please tell them Carl Hayden High School team 842 sent you.

[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.