2016 Boulder weight issue
 

All,
Has anyone received multiple FIRST boulders or ones from Gopher and compared the weight? We received 6 of the Gopher balls today and they are different weights and only 1 was close to the official FIRST boulder we received in our Kit of Parts. Some of the weights are so different that we think that they will shoot differently. Let me know your thoughts.

Re: 2016 Boulder weight issue
 

Please post the weights you measured.

Re: 2016 Boulder weight issue
 

Official FIRST boulder - 292 grams
Gopher boulders were 326, 358, 359, 359, 362 and 388 grams.

Re: 2016 Boulder weight issue
 

How do they compare in terms of surface texture, firmness, and size?

Re: 2016 Boulder weight issue
 

perhaps the colors are related to the mass?
This is an issue with frisbees where the titanium in the dye make the white frisbees stiffer.

Re: 2016 Boulder weight issue
 

We are not finding any other real difference other than the weight. We ordered the 6 pack rainbow colored balls the same day of kickoff and they just arrived today. Hoping others can check theirs to compare as well. We would also like to know if teams have a couple of the official boulders to see what the weights are of theirs.

Re: 2016 Boulder weight issue
 

Can you label the weights you posted with that Boulder's specific color? I'm interested to see if other teams who also bought the rainbow 6 pack find that their respectively colored Boulders weigh the same.

Re: 2016 Boulder weight issue
 

Given the humidity in Duluth is just about zero it's possible that the one that's been in town for 2 weeks is much drier than the new ones.

Re: 2016 Boulder weight issue
 

Here are weights by color.
Yellow - 359
Orange - 326
Orange - 362
Purple - 358
Purple - 359
Blue - 388

I take it nobody else has received these yet to compare? Has anyone received multiple gray FIRST boulders yet to compare?

Re: 2016 Boulder weight issue
 

Our KOP ball is 281 grams. We got two more from andymark in week 1, and they weigh in at 289 and 285 grams. I'm surprised that some of the balls could weigh 30% more, pretty interesting. Hopefully the ones at competition will be from the same batch...

Re: 2016 Boulder weight issue
 

We measured our 4 grey boulders at

283 g
284 g
288 g
292 g

Re: 2016 Boulder weight issue
 

Seems like the gray boulders are pretty consistent(in mass at least) and the colored ones are different. Anyone else ordered colored balls and measured them?

Re: 2016 Boulder weight issue
 

Here are the weights for ours, our scale only measures to the nearest 5g:

Original in KOP: 295g

New FIRST boulders (grey) recieved yesterday:
285g
285g
300g

Of much greater concern to our team is the remarkable increase in stiffness of all of the new balls. Our shooter compresses the ball, so the new stiffer balls slow the motors more and travel significantly less distance. We set up a jig to measure the force required to compress each ball to 8 inches. Results...

Original KOP Ball:
6,300g

New Balls:
11,860g
11,235g
12,890g

We don't know how much of this is due to the older ball being broken in, but we don't believe that it ever flew that poorly even when new. So is it an issue with differences in the foam from batch to batch or was the first ball just an outlier?

We will post a picture of how we measured the compression. If you can obtain data for your own boulders to compare, please post them as well.

Image: to be posted soon

Re: 2016 Boulder weight issue
 

We have not bought any due to the pricing but I am curious as the fluctuation in weight.

Re: 2016 Boulder weight issue
 

We are wondering about the diameter of the balls, having only 1 ball, we can't compare weights, but the manual says the ball is 10" diameter, but ours is measuring as 9 5/8th.

Anyone else noticed this? We are wondering if it has to do with our altitude, (almost 5000 ft) and how competing at lower altitude could affect our shooter if the size changes this much.

Re: 2016 Boulder weight issue
 

This compression issue arose in 2012. Wise teams will design shooters that hit the target regardless of compression status.

Re: 2016 Boulder weight issue
 

The Yellow and the 2nd Purple ones are good.:)

Re: 2016 Boulder weight issue
 

For a ball meant for playing dodgeball it seems like a reasonable margin or error.

The solution in my mind is to minimize the projectile weight's effect on your trajectory. Basically shoot that s.o.b as fast as possible. Then you minimize the arc in the shot and hence minimize the necessity for a perfectly normal weight in your projectile.

Granted, this wont work if your ball is REALLY light or REALLY heavy.

Re: 2016 Boulder weight issue
 

The balls aren't sealed, or at least ours is not. It has one small (0.1" -ish) orifice in the outer covering, so I would not expect any difference in diameter due to changes in barometric pressure.

The ball that came in our KOP measures 9.7" in diameter at 300 feet above sea level and weighs 290g.

I'll attempt to weigh and measure my teams boulders but we bought a couple of the gray boulders and not the rainbow pack.

Re: 2016 Boulder weight issue
 

While we didn't take any measurements of it, I definitely remember our ball being much harder to compress on kickoff day than it is now. My initial impression was that it had about 3/4" of foam over a stiff core, now it's clearly memory foam all the way through.

Re: 2016 Boulder weight issue
 

We just received a six pack of the colored balls from Gopher. The are different than the original ball/boulder received in the kit of parts. The balls are heavier and significantly less compressible.

Re: 2016 Boulder weight issue
 

The surface is porous, so the boulders shouldn't necessarily change with altitude.

Re: 2016 Boulder weight issue
 

Can you please weigh them and list their respective color?

Re: 2016 Boulder weight issue
 

Team 1625 has 10 boulders ordered from Andymark and our 1 KOP boulder.
Our KOP ball has weighed in 281.22 g
Andymark Boulders
3 at 290.30 g
6 at 285.76 g
1 at 281.22 g

Re: 2016 Boulder weight issue
 

Your high school's chemistry lab may have triple-beam balances. You can get very accurate measurements with those.

My O'Haus triple beam goes up to 610 grams.

Re: 2016 Boulder weight issue
 

For diameters see: http://www.chiefdelphi.com/forums/sh...d.php?t=141606

Re: 2016 Boulder weight issue
 

Wave Robotics Boulders:
KoP: 282.6 grams Edit: Just realized what this was and no it was not a joke. I think I got Glenn beat :-P

Boulders from AndyMark:
Boulder 1:285.8 grams
Boulder 2:284.9 grams
Boulder 3:278.5 grams
Boulder 4:290.8 grams
Boulder 5:291.7 grams
Boulder 6:280.3 grams

Re: 2016 Boulder weight issue
 

We recieved 9 orange balls directly from gophersport. We originally ordered the rainbow colored balls but received an email asking if we were an FRC team and asked us to correct our order. Out of our 9 orange balls, 8 weighed 0.62lbs(281g) and 1 weighed 0.60lbs(272g). The KOP boulder weighed 0.64lbs(290g). If you are ordering from gophersport the correct item number is 99-634 for the FRC version and they are ordered individually.

Re: 2016 Boulder weight issue
 

MakeShift Boulders (from AndyMark):

Boulder 1: 284.4 grams 10" diameter
Boulder 2: 289.7 grams 10" diameter
Boulder 3: 285.6 grams 9-1/2" diameter
Boulder 4: 291.3 grams 9-1/2" diameter
Boulder 5: 287.5 grams 10" diameter

Re: 2016 Boulder weight issue
 

We noticed this as well, and we're at 577ft so I'm sure that's not it :D . We haven't dimensioned the two additional balls we purchased, but the KOP ball definitely comes in at a little less than 10." We haven't massed any of them, but if the humidity has to do with it, the balls should equalize over time. Those of you who have posted ball weights, if you are able to provide your shop's temperatures and humidity, I'd like to start organizing some of this data more nicely.

Re: 2016 Boulder weight issue
 

When I massed our boulders today, they were quite consistent. We only have grey, FIRST branded balls from Andymark.

Original KOP boulder: 283.3g
Additional boulders from Andymark:
285.8g
286.6g
284.2g
285.5g

Re: 2016 Boulder weight issue
 

Here are our weights. All AndyMark Boulders.

1 272.13 kick off ball
2 283.14
3 293.48
4 282.39
5 284.73

Re: 2016 Boulder weight issue
 

I made a spreadsheet for the gray boulders listed in this thread here: https://docs.google.com/spreadsheets...it?usp=sharing

If anyone has more boulders to add, please do so!

Statistics so far:
Avg mass: 286.3 grams
Standard deviation: 4.72
Standard deviation (as percentage of total mass): 1.65%

Re: 2016 Boulder weight issue
 

Can't wait to see the spreadsheet in a little bit. +1

Re: 2016 Boulder weight issue
 

S All the boulders Code Orange has ordered have come in and here is the information we have gathered. We have 12 gopher balls, one KOP ball, and 10 andymark balls.

A=ball number
B= circumfrence
C= diameter
D= vendor
E= weight

Thanks!