What to use for ballast

FIRST General Forum
#21

As stated above, COTS vs FABRICATED doesn’t really matter, unless you’re adding it after the bagging this Tuesday.

I expect that we’ll wind up using some steel “uni-strut” channel, possibly hammered (closer to) flat, simply because we already have it in-house and it’s heavy.

I have used coins as weights before, but not for FRC - it was for a Boy Scouts “pinewood derby” competition. It turns out that a quarter equals exactly 1/5 of an ounce. Serendipitously, the third and last quarter installed on Gixxy’s car was an Indiana quarter, reverse up, and the car placed high enough within the pack to go to our region. In case anyone doesn’t know what an Indiana reverse looks like, there’s the link.

#22

My team is looking at lead bird shot ballast. Are there any issues to building a solid aluminum box to bold them in? I saw the earlier comment about in in a plastic bag.

#23

In 2009, we had two water bottles (500 mL?) filled with lead shot, their caps glued on, and the bottles zip tied to the frame. Never had any problem.

To be fair, nothing moved very fast in Lunacy.

#24

In 2013 we used a few 5lb weights (like at the gym). Worked fine, and it tells you the weight on the side!

#25

I’d think welded PVC would be a better choice. How is the box being closed?

As long as it isn’t a leak hazard… as that what the issue with the baggies were; they came loose and when hit by a robot spilled EVERYWHERE… My memory is no good but IIRC a red card was handed out for the incident, due to the downtime needed to clean up the mess on the floor (you can imagine the sound created by the vacuum, high speed pinging!) and also because the baggies were supposedly deliberately “hidden” from the robot inspectors who would have otherwise not passed the ballast as legal.

Same goes for sand and any other “granulated” ballast weights. Make sure it is sealed and well attached.

#26

The only really safe way to use lead shot as ballast is to encase it in epoxy.

#27

Corndogs.

#28

Wow!
Here a few things for you to consider when contemplating ballast from an inspector standpoint.

  1. Sand, don’t think you can encase sufficiently that it won’t pose some hazard. The capped steel pipe might work but… I had a team try to demonstrate sand as a hammer weight last year. When asked to demonstrate their containment they promptly broke the container and dumped several pounds of sand into their robot in the pit.
  2. Shot of any kind must also be suitably contained. Plastic bottles do not fit that definition.
  3. Lead, if your sponsor/build space/school allows you to handle it, must be fully encased and untouchable at competition. We have allowed lead to be painted and sealed with the understanding that it cannot be machined in any way at a competition. Many local ordinances and venues prohibit it’s use.
  4. To reiterate sash weights, you need to know the material as it varies in the part of the country you live and the era in which they were made. (See lead above)
    In all cases, ballast needs to be firmly attached to the robot with fasteners. Ty-wraps, duct tape, etc. are not considered fasteners for this application. Personally I like big hardware with locking nuts.
    R8 is pretty specific, if your ballast has the ability to come out of your robot and damage another robot, a volunteer, or the field (shot or sand dumped on the field comes under this heading) it violates R8.
#29

Yeah, we found out the hard way this year that exposed lead is a no-no. I really wish that it had been explicitly stated that it cannot be exposed In the manual under the hazardous material section. We used lead dive weights, which as a diver I don’t consider them hazardous in that form. Long short one of the safety crew said he thought we needed to call a Hazmat crew out to perform cleanup! :ahh:

Maybe FIRST could provide us with a standard from EPA, OSHA, UL, or some other organization so that we can be informed of proper rules.

Edit: not bellyaching, just trying to let others know so they don’t put their students in an uncomfortable situation.

#30

You mean my 50 lb glass vial of mercury as robot ballast won’t fly during inspection? What if I just hide it really, really well? Guess I’ll change that to a small steel cylinder of Hydrogen, Oxygen, or Acytelene then.

No…lead and mercury are both “Hazardous Materials.” (As are the others I listed). If added to your Robot that is.

Now, where did I attach that compact 20 lb. nuclear weapon I used as ballast the last time it was needed? (Use simple common sense please).:wink:

Edited for Addition;
Sure enough I missed reading Al’s #3 fully above…(Wouldn’t even attempt that personally, due to the multiple venues, schools, and commercial arena’s, we compete at in multiple jurisdictions each season, not to mention that eventually someone may wish to resize the ballast for wt. reduction eventually). Sry Al.

#31

why not use that extra weight to add functionalities or make your robot stronger?

#32

Hyperbole is neither gracious nor professional.

#33

We used “Thirt” a solid aluminum cylinder for ballast in 2013 for our pyramid climber - and won Pine Tree with it.

Excerpt from our team website:

The Windham Windup, FRC Team 3467 Presents out mascot, Thirt!

Thirt is a solid piece of aluminum stock, 6 inches long with a diameter of 3.5 inches. He got his name because the atomic number of aluminum is 13.

Thirt became a member of our lives back in 2013, at the Granite State Regional. As a result of having some troubles with our robot, our shooter was removed, leaving only our climbing mechanism. Our sponsor, Veloxion, brought him to us as a counter-weight to move our center of gravity to directly below the arm. Because of him, our climber worked perfectly, allowing us to go on to win the Pine Tree Regional, and get an Excellence in Engineering Award specifically for our climber.

After GSR, our lead programmer fell in love with Thirt. He provided Thirt with his name and status.

The Windham Windup’s Ultimate Ascent robot went from being a robot without a shooter to a robot that brought its team to the World Championship, thanks to Thirt. Because of this, Thirt has become a symbol of 3467’s motivation and success.

Unfortunately in the years after 2013 we haven’t had any weight left to use for ballast :wink:

#34

Do realize that if you ride in a motor vehicle with wheels, you likely have exposed lead weights on your wheels. Don’t lick them.

One 18 lb counter weight we used is a plastic encased lead / sulfuric acid mix. The inspector didn’t even count it against our weight limit. The other was a 4"x21"x1" chunk of steel. About 20 lb

#35

We put rebar into our back 2x1 of our west coast chassis. Works like a dream, and it not visible at all (we made custom plugs).

#36

Please don’t ‘joke’ about this. Duct taping ‘ballast’ to your robot will not make your inspector or FTA happy.

#37

We use 1" x 3" steel bar cut to the precice length needed. Adjustable to any weight, fits in tight spaces, and easily drilled and tapped for mounting. No one knew, but there was 11.5 lbs. of such bar hidden inside the rear of the chassis of our 2013 robot, to manage CG for level hanging.

#38

This is a year where ballast is definitely a possibility for many teams.

My prognostication from game reveal day, and at least somewhat supported by week 1-3 results: This is going to be a landmark year for specialization and complementary alliance selection.
Even if I’m wrong, this is not an unreasonable place to be; several threads on CD have even focused on which specialties will be in demand. With that as a given, many robots will be simpler than in recent years, and will come in *functionally *under the weight limits. A significant number of these, (especially those whose design placed emphasis on mining the landfill, capping stacks, or scoring coop points on the step), will carry game pieces outside of the traditional “frame perimeter”, and will be greatly assisted in stability by a chunk of metal at the back and bottom of the robot.

#39

Uranium could make a pretty heavy ballast as well

#40

We came up with a fairly ingenious solution this year for ballast, we are using a 1" threaded rod the length of our back tube and we increment nuts on until we have our desired weight. Each 1" nut wights about 1/4 Pound which gives us all the variability we need. Another plus you touched on is its all COTS and fairly cheap (we found the nuts for under a dollar per and the rod was about $20)