Disc Weights

[Frank Delicious]

I know % wise its not much, but with some discs it makes a bigger difference than others.

But relative to the others things that can affect how a disc flies, a few grams is not that big of a deal.

Also saying it affects certain discs more than others isn't really saying anything, you are just saying all discs aren't the same.

 

[GLong]

yea i know its not a big deal, im agreeing with you for the most part. i just want to know. and i have a scale. so i weigh them. outside of weight, the only things that affect how it flies are:

1. thrower technique
2. condition of disc
3. weather

all i can really control are throwing discs that are pretty much the same weight in the same condition. this allows me to make assessments on my technique and make adjustments for wind etc without really thinking about the discs.

im saying that it affects putters more because they often arent flying that far - a few grams really starts to affect the glide on shots outside of 40 feet or so. trust me - find yourself a 179/180g putter if you can and throw that next to whatever you normally throw. the flight will be significantly different compared to throwing two distance drivers that are 171 versus 175g or whatever.

 

[garublador]

This thread is a great example of congantive dissonance. People claim it would be easy for the manufacturers to weigh the discs accurately, but none of them even acknowledge the fact that the discs change weight after they're shipped. How can you claim that the measurements they took are inaccurate and that there's something they can do to predict the environment the discs will be subjected to when the effect on the disc weight is less than 3%? Also, how many have a certified weight that's approximately 170g to prove their $30 food scale is as accurate as they think in that range?

 

[toothyfish]

Based on variables (moisture content, etc) it would be difficult to say. I didn't think about that when weighing mine, but I would typically weigh a whole pile all at once, so I could at least get an idea. If I had a bunch that were close, maybe 1 gram over, and than one that was 3 grams over (or under), I could say that there is an issue with that one, because I did a whole bunch at a time to establish normal variation.

What could be done is if ALL your discs were stored in the same place for an extended period of time (say, in your living room, under normal temp/humidity conditions) you could then weigh ALL your discs and see their weights relative to each other. It wouldn't be accurate to weigh discs stored in the trunk of your car vs. the ones hanging on the wall in your den.

It would have to be done on a scale with an accuracy of 0.1g with that repeatability. While most scales with type of accuracy/repeatability are $200+, there are versions available for $70ish. Repeatability is crucial. Just because the display will show the digits, you need to know that each time a disc is removed and another one placed on, that the scale will accurately read. Try weighing the same disc 10 times in a row, and see what numbers you get.

Ohaus makes one that can handle up to 200g ±0.1 g. I thought about buying one, but I have access to really nice ones where I work.

 

[Frank Delicious]

yea i know its not a big deal, im agreeing with you for the most part. i just want to know. and i have a scale. so i weigh them. outside of weight, the only things that affect how it flies are:

1. thrower technique
2. condition of disc
3. weather

all i can really control are throwing discs that are pretty much the same weight in the same condition. this allows me to make assessments on my technique and make adjustments for wind etc without really thinking about the discs.

im saying that it affects putters more because they often arent flying that far - a few grams really starts to affect the glide on shots outside of 40 feet or so. trust me - find yourself a 179/180g putter if you can and throw that next to whatever you normally throw. the flight will be significantly different compared to throwing two distance drivers that are 171 versus 175g or whatever.

Two discs that weigh the same but have different parting lines will fly much more different than two discs that have the same parting line but weigh a few grams different.

Also what Garu said.

 

[Dfwdscglfr]

kinda off topic but how do u read parting lines for stability and stuff sorry for jacking

 

[skinner21]

frank, you keep mentioning parting line, what does that mean?

FWIW, I work in the manufacuring industry and getting exact wieghts and marking every disc exactly would be impossible, and that's neglecting the fact that, like everyone else has said, discs change over time. To get a disc to be able to make into the consumers' hands in exact factory condition would require additional packaging, transportation methods, and manufacturing processes. Expect that to add a lot of cost to your discs. My advise would be to get over it and wiegh discs yourself, but I highly question the accuracy of home scales. Even industrial scales require fine tuning and adjustments to stay highly accurate. These home scales are nice to have, but they can easily be off by a gram or more. Considering one gram is .6% of a 175 gram disc, I would expect it to be off by at least that much.

 

[toothyfish]

Parting line - where the top and bottom portions of the mold meet. On the outide of the rim, you can see a very subtle line (like a small ridge)

 

[skinner21]

Parting line - where the top and bottom portions of the mold meet. On the outide of the rim, you can see a very subtle line (like a small ridge)

thanks. How do you evaluate this parting line and how does it affect flight?

 

[toothyfish]

thanks. How do you evaluate this parting line and how does it affect flight?

Sometimes there can be variation in where the top and bottom of the mold. As the mold wears, etc, the bottom may stick out past the top and vice versa. It would have some impact on flight, how big, I don't know.

But with regards to weight, verifying the exact weight at the factory would require that the discs be weighed in such a way that the influence of environment is reduced or at lease the variation. Weighing right off the mold would be best.

As far as variation, ±1 gram is no big deal. I do think ± 3 is too big, especially since that means a 170 and a 175 could both weight 172.5 and still be considered in spec. My 3 cents.

Hey, what kind of variation do you think they get with the RW stuff? Wood? Really? In a disc? My deck boards expand and contract 1/4" or more as they get wet and dry over their 5.5" width.

 

[bikinjack]

Here's something from Dave McCormack

http://www.gdstour.com/how_disc_weight_affects_hi-speed_drivers.php

 

[Marmoset]

kinda off topic but how do u read parting lines for stability and stuff sorry for jacking

Here's a detailed DGR thread talking about PLH.

Here's another.

Within a set of discs that came from the exact same mold, the higher the PLH the more overstable it is. Read the links I included if you want specific examples, measurements, etc. ***Warning- links take you to DGR; I kno wsome of you guys hate DGR***

 

[AdamCaudle]

You can clearly see the parting line on a Shark if I'm not mistaken?

 

[ERicJ]

That thing looks awesome. I have always wanted to buy a kitchen scale for $30, but that seemed too much for just weighing discs. If it works well it seems like a deal. Anybody have one? Thanks ERicJ!

Posted in the "scale" thread:

I picked up one of those when they were on sale for $7.50.

So far it works really well. The only issue you'll have for weighing discs is that the scale is too small to weigh a disc and still see the reading on the scale. But that's easily fixed by using a small cup (or similar item) to place on the scale to elevate the disc. Tare out the scale with the cup and then weigh the disc.

 

[ERicJ]

they weigh them in stacks and then divide the weight by the # of discs weighed and that is what they write on the discs.

What's your source for that?

It seems pretty unlikely given the consistency of measurements I've seen on hundreds of discs so far.

 

[Frank Delicious]

What's your source for that?

It seems pretty unlikely given the consistency of measurements I've seen on hundreds of discs so far.

I looked for the some quotes on DGR but couldn't find them because our search feature is crapping itself server side but I remember a couple of guys who worked in factories (wanna say Mill or Gateway) saying that is how they did it. Plus I think it's been mentioned in this thread by someone besides me.

 

[Frank Delicious]

also you might be the only one who says there is consistency in weight in this thread.

(note: I agree, most discs I have are spot on or very close)

 

[sidewinding]

Here is what I found when I weighed 36 discs on a Pitney Bowes certified mail scale:

12 were same as marked
7 were 1 gram more than marked
1 was 1 gram less than marked
5 were 2 grams more than marked
1 was 2 grams less than marked
6 were 3 grams more than marked
2 were 3 grams less than marked
1 was 4 grams more than marked
1 was 5 grams less than marked

In other words 33% were accurately marked.
56% were accurately marked within +/- 1 gram.
72% were accurately marked within +/- 2 grams.
28% were off by 3 grams or more.
<1% were off by 4 grams or more.

These discs were clean and had been in my +100 degree trunk all day which you'd think would rule out moisture absorbtion and none of them were excessively worn which you'd think would rule out major weight loss.

And the scale I used was accurate +/- 0 because I weighed a disc 20 times and got the exact same weight.

 

[`cjc]

I've got a disc that is labeled as a 173, but actually weighs 178. I thought it was weird when it had more fade than another of the same disc that was actually 175, then I weighed it, and then I knew. This particular mold is only approved to 176.8. I wouldn't have cared, and really don't care, but the flight pattern is noticeably different.

I had as similar situation with a 175, it weighed 178.8 and it's technically illegal. It's been thrown 10 times or so and I don't use it anymore.

 

[ERicJ]

My only question is: with Innova or Gateway the weights are written on by hand. I would assume that means they are weighed by hand. It's not like they are weighed by a machine or something and given a weight range stamp like Discraft discs.

Note that Discraft has started hand marking "exact" weights on their discs as opposed to using the old weight range stickers.