What to use for ballast

[Victor_os]

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

[madhav]

Originally Posted by Tyler2517

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

Clamping it, what a great idea!

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

[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

[Mr V]

Originally Posted by Victor_os

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

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.

[nighterfighter]

Originally Posted by Mr V

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.

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.

[Retired Starman]

Originally Posted by nighterfighter

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.

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!

[nighterfighter]

Originally Posted by Retired Starman

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!

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

[JamesCH95]

Originally Posted by nighterfighter

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.

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!

[Gregor]

Originally Posted by JamesCH95

Besides, pennies are expensive!

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

[PAR_WIG1350]

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.

[GreyingJay]

Originally Posted by JamesCH95

Besides, pennies are expensive!

And getting much harder to find in Canada!

[JamesCH95]

Originally Posted by Gregor

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

Canadian or US?

Originally Posted by PAR_WIG1350

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.

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

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

Originally Posted by GreyingJay

And getting much harder to find in Canada!

Darn!

[GreyingJay]

Originally Posted by JamesCH95

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

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

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?

[Al Skierkiewicz]

Originally Posted by 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

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