So I’m new to coaching VEX, previously worked 7 years with BEST, so I’m still trying to get used to some of the differences between builds. I have some students on one of my teams who are trying to build a claw arm but are afraid the claw with the star will be too heavy and would like to add a counterweight. They would like to screw two smaller C-channels together and fill them with spare nuts or screws to use as weight. Is this a legal move, or will it be an issue since that’s not the intended use of the nuts and screws? Thanks in advance for any help! Definitely appreciated 
Yes, this legal and creative! You’ll need to make sure that the screws are secured such that they don’t fall out of the channels.