What to use for ballast
 

Our team needs to add some ballast to our robot, and we're trying to decide if we can use some donated sash weights from old windows. Does that count as a COTS part? What about weights from old barbells? What does your team use for ballast?

Thanks!

Re: What to use for ballast
 

Whatever you do, don't use bird shot as ballast.

#crossroads2014

Re: What to use for ballast
 

Ballast?? How nice it would be to have to add.. In our 5 years we have only had to add weight once.. And we used steal bar since it was easiest to weld on attachment mounts.

I am interested in what others have to say about this..

Good luck!

Aloha.

Re: What to use for ballast
 

A table top vice clamped to your frame works nice.....

Re: What to use for ballast
 

Weld all your scrap metal together and duct tape it to your robot. That works right..?

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Extra batteries, oh wait..... :rolleyes:

Re: What to use for ballast
 

Our team melted old tire weights we got from an auto repair shop and filled 1x2 aluminum tubing with it. An 8" piece ended up around 4 pounds when done. Worked well for us and is easily mounted into the chassis plus it fits with the theme of the game...right? Reuse and recycle.

Re: What to use for ballast
 

In loose thin pooly attached plastic baggies that is. :eek:

I hear bench press weights work well.

Re: What to use for ballast
 

We haven't to add extra weight on our root in FRC but our one of our BEST teams needed to add extra weight, they added 10 lbs of pennies. We might just add 10lbs of pennies if we need it.

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In 2013, we zip-tied a .5"x18" steel bar to the back of our robot. Basically any easily-mounted steel object will do just fine.

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On the BOM do you list the pennies as a whole, or are they exempt because each one is under $1?

We were going to use 3 or 4" PVC pipe with a cap glued on one end and a spin off on the other, and fill with sand. Easy to secure and you can adjust the amount of sand if needed. Oh and easy to source and cheap!

Re: What to use for ballast
 

Re-position the battery to shift the robots center of gravity. Otherwise a chunk of steel should do the job

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Be careful when using sand per R8-J. I don't interpret that as a hard ban on sand, but it's definitely not legal if it can get all over the field.

Re: What to use for ballast
 

On the subject of adding pennies for weight (which I actually suggested to my team on Sunday, half jokingly, but for decoration instead...):

1 penny = $.01 = 2.5 grams
1 Nickel = $.05 = 5.0 grams
1 Dime = $.10 = 2.268 grams
1 Quarter = $.25 = 11.340 grams

1 Pound = 453.592 grams.

This means to get 1 Pound of ballast weight using each common U.S. coin, you would need:

Pennies: 181.4368 = 182 = $1.82/lb
Nickels: 90.7184 = 91 = $4.55/lb
Dimes: 199.9964 = 200 = $20/lb
Quarters: 39.99929 = 40 = $10/lb

(Source: http://www.usmint.gov/about_the_mint...specifications)

Therefore, the most economical coin to use as ballast would be pennies. But if you really want to show off, use Dimes!

Even more fun: You can probably get MOST of those pennies for free...have every student check under their couch! :p

Or, if you are really rolling in the dough, use the Presidential or Native American $1 coins, needing 56 to make just over a pound!

We had discussed that, but weren't worried about making a mess. Plus we are right at 119lbs with out battery or adding weight so even more of a non issue.

Re: What to use for ballast
 

I suggest a cast iron bust of Mr. Kamen himself. Perhaps a second one of Mr. Flowers if need be.

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A nice length of 1018 steel is a good choice, but you need to drill holes which makes it non-cots.

Other ideas I've seen (but don't necessarily endorse):

Sand in sealed PVC pipe
Sand in black pipe
Cast scrap metal blocks
Concrete casting
Kitty litter (Dallas 2009)

Re: What to use for ballast
 

It doesn't have to be COTS to be used as ballast. If it is not on the prohibited materials list it is fair game. Some of the things that are not allowed are lead unless it is fully encapsulated so there isn't any skin contact or a way for dust/chips to be generated. Things like pennies, washers, ball bearings or other loose items must be in a robust container so that they will not dump all over the field if the robot tips over.

So the question is what are the sash weights made of?

The rookie team I am helping out is using sash weights as they are at a very old school and there is a stack of them in the maintenance shop. They are cast iron, though that doesn't mean yours are.

We had a steel bar, roughly 2x4 and we would cut off pieces as needed. We let a few teams take some pieces at various competitions, let's just say the machine shop wasn't very happy with us. Milwaukee couldn't cut it so we had to take it to the college across the street to cut.

Re: What to use for ballast
 

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.

Re: What to use for ballast
 

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.

Re: What to use for ballast
 

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.

Re: What to use for ballast
 

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

Re: What to use for ballast
 

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.

Re: What to use for ballast
 

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

Re: What to use for ballast
 

Corndogs.

Re: What to use for ballast
 

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.

Re: What to use for ballast
 

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.

Re: What to use for ballast
 

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).;)

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.

Re: What to use for ballast
 

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

Re: What to use for ballast
 

Hyperbole is neither gracious nor professional.

Re: What to use for ballast
 

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 ;)

Re: What to use for ballast
 

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

Re: What to use for ballast
 

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).

Re: What to use for ballast
 

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

Re: What to use for ballast
 

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.

Re: What to use for ballast
 

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.

Re: What to use for ballast
 

Uranium could make a pretty heavy ballast as well

Re: What to use for ballast
 

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)

Re: What to use for ballast
 

Our ballast is a 250c Viair compressor and a 1/4 inch thick aluminum bellypan. due to upgrades at next regional, one has to go. I really like that compressor and replacing the bellypan doesn't sound terribly appealing either:)

Re: What to use for ballast
 

Actually lead wheel weights have been outlawed in some states. http://www.leadfreewheels.org/ In addition the EPA has been "strongly suggesting" that tire stores choose lead free weights and that states ban the use of lead wheel weights.

Of course there are still millions of cars on the roads and wheels out there with un-coated lead wheel weights.

Re: What to use for ballast
 

Jimbo,
Had you been in California, it would have been a much different situation. Sealing/painting lead ballast is not something new to FRC. It has been around for more than a decade.
Lead wheel weights are also out of fashion for the same reason. Many locales do not allow them and some states ban hundreds of materials altogether.
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.

Re: What to use for ballast
 

Al,

Are you stating that the battery used for power on the robot cannot be used for ballast?

Hmmm, seems I need to figure out how to power my robot then ;)

Re: What to use for ballast
 

Anyone who read your Bill Of Materials should have been aware of its existence. Unless by "hidden" you mean "secret", in which case you were were not in compliance with the rules.

Re: What to use for ballast
 

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.

Re: What to use for ballast
 

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.

Re: What to use for ballast
 

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!

Re: What to use for ballast
 

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)

Re: What to use for ballast
 

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.

Re: What to use for ballast
 

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.

Re: What to use for ballast
 

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.

Re: What to use for ballast
 

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

Re: What to use for ballast
 

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.

Re: What to use for ballast
 

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

Re: What to use for ballast
 

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.

Re: What to use for ballast
 

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.

Re: What to use for ballast
 

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 :p

Re: What to use for ballast
 

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.

Re: What to use for ballast
 

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

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

Re: What to use for ballast
 

You can sand to extrusion. Fill them up of add a bag of pennies.

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Clamping it, what a great idea!

We just duct-taped it on top of our practice bot.

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

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!

Re: What to use for ballast
 

Attachment 18684
Team 1796 did this at the NYC Regional

Re: What to use for ballast
 

A bag of pennies or anything in a bag is not acceptable if the bag were to open or tear the contents could be strewn about the field. Sand in a length of extrusion unless it has a robust method of keeping it closed would also be frowned upon for the same reason.

Re: What to use for ballast
 

What about putting the pennies inside a double-bagged zip-loc bag, inside a tupperware container, and putting the tupperware container inside a bag with a drawstring/zipper to close it? (Similar to this: http://www.usflash.net/ProductImages...uch500X500.jpg)

This would provide multiple layers of spill-prevention.. The ziploc bags probably won't jostle open, and the tupperware container provides a hard casing to prevent the bags from small puncutres. Then the bag with the drawstring provides an additional layer of containment, if the tupperware breaks open and spill the pennies, they would be contained inside the bigger bag.

You could also just epoxy some shiny pennies to your frame! That will probably look cooler.

Re: What to use for ballast
 

As in any design project, you do your due diligence and go ahead. As an inspector, I would look at your pennies in layers of protection and probably approve it with the stern warning that the Head Ref will not be happy (or your friend) if he/she sees pennies all over the playing field. Nun said!

Re: What to use for ballast
 

Fair enough. (Not that we actually planned on doing that, just offering a hypothetical suggestion if someone wanted to use pennies/coins).

Re: What to use for ballast
 

If you need a triple-redundancy in your ballast you're doing it wrong. I know this was just a hypothetical, but I want to hypothetically discourage teams from opening this can of worms (bag of pennies?)

Besides, pennies are expensive!

Re: What to use for ballast
 

Is a bag of 101 pennies less than $1, BoM wise? :rolleyes:

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You could easily contain pennies in a length of EMT with the ends crimped shut. Plus the metal tubing adds to the weight, which reduces the number of pennies needed.

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And getting much harder to find in Canada!

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Canadian or US? :p

I'd prefer to get some of those coins with holes in them and bolt them down. :cool:

(or... you know... some washers...)

Darn!

Re: What to use for ballast
 

But pennies are cheaper than washers!

(Except in Canada where we no longer have pennies... we'll have to use nickels!)

But a Canadian nickel is worth about an American penny these days, no? :rolleyes:

Re: What to use for ballast
 

You were lucky, these devices (velcro and duct tape) are not considered fasteners for ballast and should not have been allowed.