What to use for ballast

[JamesCH95]

Tungsten, being the densest material you can buy on McMaster.

Or, you know, scrap steel that can be had for free from almost anywhere...

We've taken a metallic pneumatic storage cylinder and filled it with all of the scrap metal, chips, bolts, etc that we can cram into it. A neat, safe, adjustable method of adding ballast. And it seals up really nicely with a few 1/4-npt plugs.

[GreyingJay]

Originally Posted by vhcook

Have you modified the dumbbell? If it is an unmodified dumbbell, it should be a COTS part, and does not count toward withholding. If it has been drilled or otherwise machined to facilitate connection to the robot, then it is not COTS anymore, and does count.

This is how I understood the rules, but I keep being told by other people on my team "no, we can't bring weights".

Bringing a COTS weight, such as a dumbbell or a piece of steel bar, and figuring out how to modify it AT the event to attach it to the robot (assuming that velcro straps are unacceptable), is legitimate, according to how I read the rules.

Originally Posted by JamesCH95

We've taken a metallic pneumatic storage cylinder and filled it with all of the scrap metal, chips, bolts, etc that we can cram into it. A neat, safe, adjustable method of adding ballast. And it seals up really nicely with a few 1/4-npt plugs.

But that makes it not a COTS part, right? So this cylinder-full-o-junk is considered part of the 30 lbs? But if you bring the empty cylinder, the plugs, and a bag of bolts and put it all together at the event, then it's not?

Sorry if this seems like a n00b question, I'm new here and still trying to figure out the rules

[Mr V]

Originally Posted by GreyingJay

This is how I understood the rules, but I keep being told by other people on my team "no, we can't bring weights".

Bringing a COTS weight, such as a dumbbell or a piece of steel bar, and figuring out how to modify it AT the event to attach it to the robot (assuming that velcro straps are unacceptable), is legitimate, according to how I read the rules.



But that makes it not a COTS part, right? So this cylinder-full-o-junk is considered part of the 30 lbs? But if you bring the empty cylinder, the plugs, and a bag of bolts and put it all together at the event, then it's not?

Sorry if this seems like a n00b question, I'm new here and still trying to figure out the rules

Us it is perfectly fine to bring an unmodified weight in and it will be considered COTS. No Velcro would generally not be considered suitable for holding ballast of any significant weight and neither would duct tape or zip ties.

You are correct that the cylinder filled with misc "junk" is not a COTS part so it would be part of the 30lb withholding but if the cylinder and the "junk" were brought in separately then it would be a collection of COTS items and not a fabricated assembly.

[gurellia53]

We had a lead plate attached to the bottom side of our robot last year. It worked wonderfully as ballast...

We didn't know about the possible restrictions on this material. We just bought it from McMaster and bolted it on.

[JamesCH95]

Originally Posted by Mr V

You are correct that the cylinder filled with misc "junk" is not a COTS part so it would be part of the 30lb withholding but if the cylinder and the "junk" were brought in separately then it would be a collection of COTS items and not a fabricated assembly.

This is how we put it together since we didn't know until weigh-in what our weight situation was.

Originally Posted by gurellia53

We had a lead plate attached to the bottom side of our robot last year. It worked wonderfully as ballast...

We didn't know about the possible restrictions on this material. We just bought it from McMaster and bolted it on.

You didn't think it would be a bad idea to bring an (I assume) raw form of known carcinogenic and toxic material into close proximity with people who may or may not have any idea it was there?

Well, I strongly encourage you to review your safety and MSDS practices!

[mhos1997]

Team 1796 did this at the NYC Regional