What to use for ballast

[Al Skierkiewicz]

Daniel, Of course not!
An "One 18 lb counter weight we used is a plastic encased lead / sulfuric acid mix" conjured an image in my mind of a larger battery than the robot battery. This is due to FRC legal batteries are between 11 and 13 lbs depending on type and wire.

[Jimbo2032]

Al,

In the future it (sealing/painting) will definitely be something we do. However, by reading the the game manual there was no way to know that was a common practice. Why, just a year or two ago we had an inspector gauge the perimeter of our robot with a home made 'plumb bob', made from fishing line and a raw lead sinker.

Being from rural Georgia, where gun racks hung students trucks in the parking lot don't raise an eyebrow, and lead sinkers are cast from discarded wheel weights after school, it never occurred to us (mentors or parents) that others may have an issue with our ballast choice. Rest assured that in the future we will make it a point to use the coated style (unless those are outlawed). I've been needing a good excuse to buy new dive weights for a while anyways!

Just goes to show you don't know what you don't know. And I'm sure as the years go on we'll find new and exciting ways to discover taboos the hard way.

[Retired Starman]

All of us in the over 50 group probably have significant brain damage from breathing the fumes from automobiles which all ran on leaded fuel up till the mid to late 1970's. Lead by-products were everywhere in the air and you couldn't get away from them.

We would probably have all been geniuses if it hadn't been for leaded fuel.

Babble On!

[carpedav000]

One thing that definitely became our go-to counterweight this FTC season was tungsten (we had about 8-10 lbs in various places of our frame)

[FrankJ]

Originally Posted by Al Skierkiewicz

Frank, I assume you are speaking of a battery used as ballast. Again this violates Robot rules and an issue was posted during last season here on CD discussing it.

You are allowed one. Doesn't even count against your weight allowance. Place it where it does the most good. Also where it is not likely to be damaged. Last year's CD discussion does not count for this years rules. 2015 rules are very clear though. Only one SLA battery on the robot. Sorry, off on the weight. Must come from years of breathing leaded gas fumes.

On a serious note, although solid lead does not pose much risk, chemical exposure in general can have short & long term effects. Avoiding unessesary exposure & using the right PPE is really important. The brain you save might be your own.

[Al Skierkiewicz]

Jimbo,
Sorry that this wasn't more apparent. I have been discussing this so long, I do forget that some are seeing things for the first time. In the history of things, dating back to about 2000, teams were predominantly east or west coast and Canada. California has strict laws on lead (starting in 1991, revised in 2000 and then revised again in 2007) and I remember that prior to my start as a robot inspector, lead was not allowed to be machined in the pit. Someone correct me, but I think lead based solders are banned from pit use in California events.

[EricH]

Originally Posted by Al Skierkiewicz

Someone correct me, but I think lead based solders are banned from pit use in California events.

I can't find it anymore, but lead-free solder used to be required per the manual--at least at the events. All events. Can't find the language banning it now though--might just fall under R8 now.

[E_puello]

In 2012 we had two 2x2x4 blocks of steel as ballasts.
They were mounted to the robot with Velcro on two of the faces of each block and duct tape on the back. Dispite what has need said of using tape to attach ballasts in this thread the industrial strength Velcro held on very well. We had trouble taking the weights off when we wanted to move them

[Fields]

Whichever weight you choose, I suggest looking at cantilevering it behind you (assuming that's the side you want heavier)

Of course, take you're robot size into account and the fact that you have a tail similar to a sledge hammer to keep track of. Since bot defense is not an issue this game, you can gain a lot with this.

[GreyingJay]

Does bringing a dumbbell to an event to strap to the robot count toward the withholding allowance?

[vhcook]

Originally Posted by GreyingJay

Does bringing a dumbbell to an event to strap to the robot count toward the withholding allowance?

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.

[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.