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View Full Version : DHS D40+ ball - broken or not?



mart1nandersson
02-20-2019, 03:29 PM
I played a league match this past weekend and we were using the DHS D40+ ball (white). My second opponent stopped play after a few points and wanted to replace the ball as he had noticed a white line on the ball similar to one in the below picture (which is an orange DHS D40+ 3*):
18580

I was completely fine with replacing the ball but it got me thinking after the game. I took the ball with me home and I've been bouncing it against a stone floor trying to detect any sound indicating that it would be broken without success. I've also pressed it hard against my kitchen table with my bat and it's not making any sounds nor cracking. I've seen these type of "pre cracks" on DHS D40+ and Stiga Perform balls in the past and they play nicely for several days if not weeks. I also did a simple roundness test by spinning it on the table and it's not egg shaped in any way.

Would you rate this as a broken ball? Would an umpire in the higher leagues discard it immediately?

zeio
02-20-2019, 03:45 PM
That's stress whitening. The good thing about celluloid is that it's hard to make that appear without breaking it.


The appearance of white line indicates that there is an onset of failure of the corresponding material...The white colour is because of the light scattering by the crazes.

mart1nandersson
02-20-2019, 04:08 PM
That's stress whitening. The good thing about celluloid is that it's hard to make that appear without breaking it.

So it's basically about to break but not broken?

Zaid323918
02-20-2019, 04:09 PM
I'm using the D40+ as well and that happens to them all the time after they've been used for a while. They play a little different and before you know it there will be a tiny crack.

mart1nandersson
02-20-2019, 04:22 PM
I'm using the D40+ as well and that happens to them all the time after they've been used for a while. They play a little different and before you know it there will be a tiny crack.

Do you typically throw them away when the white lines appear?

I play a club which uses the horrible BTY G40+ which normally breaks like a lightbulb when there's a crack in them so I've never thought about this before.

Zaid323918
02-20-2019, 04:33 PM
Do you typically throw them away when the white lines appear?

I play a club which uses the horrible BTY G40+ which normally breaks like a lightbulb when there's a crack in them so I've never thought about this before.
I won't throw the ball out until it is cracked but I'll start using a new ball for any match play and just use this for practice until it's cracked.

yoass
02-20-2019, 04:42 PM
I won't throw the ball out until it is cracked but I'll start using a new ball for any match play and just use this for practice until it's cracked.

(Ducks, well aware of the high esteem many hold these balls in…)

We actually threw out all our DHS D40+ balls, a few 100 of them. A few were good, many were horrible duds. Might have been bad luck, but if so then bad luck in multiple production batches. Which guides me To distrusting QA, and life’s too short for that.

(Yes, I could have tried returning them and beg for refunds or replacement. Like I said, life’s too short for that.)

zeio
02-20-2019, 04:45 PM
So it's basically about to break but not broken?

More or less. Though technically, it can be repaired since ABS is a thermoplastic.

https://engineerdog.com/2015/07/31/why-does-plastic-turn-white-under-stress/

Plastics can fail in one of two ways: Their molecules can quickly slide relative to each other without stretching in a process called shear yielding. This leaves behind a clean cut face and a hardened surface, but does not result in a whitened region.

The failure mode we are interested in here is called crazing. This occurs as a localized deformation that leads to the creation of voids and alignment of the molecular chains. Any area affected by crazing has undergone permanent deformation and will not move back to its original position when the load is released. The result is a highly strained area that permanently appears white.

...That’s not to say that stress whitened regions are completely irreparable. Thermoplastics, by definition, can be remelted any number of times without harm to the structure of the plastic. So all it takes is the proper application of heat to fix it.

JST
02-20-2019, 07:07 PM
We run our second 72-ball badge from TTNPP now (white D40+ 3***) and from time to time I notice such lines as well. I thought it's because we play with many balls and people from time to time step or "almost" step on one and because ABS is really hard (compared to celluloid or cellfree plastic) it doesn't break just leaves the mark. But there are slightly more such lines on our balls then recorded "stepped on but didn't break" incidents I believe it's inducted by more events. Anyway they play pretty much OK even with these and they don't break afterwards even you play 10/20/30 more hours with them. We keep them for training only anyway, checking our competition D40+ balls that they are round and without any special marks.

For the price I'm still in favor of buying more of these, I don't have any major complain (sorry yoass, I've been luckier for the batch so I haven't lost confidence as you did;). Yes, you might want to take time and select competition balls if you are really picky about the roundness, yes some of them might get these lines after strong hit, yes they tend to become darker and logo goes down when you reach long playing hours, but playing characteristics and durability vs. price are really high ratio.

usualsuspect
02-20-2019, 07:09 PM
I guess I understand why someone would want to replace this ball in a match setting.
However, I don't really consider this ball as broken. My motto is "It ain't broken until it's broken", life is too short to argue otherwise.

Zaid323918
02-20-2019, 09:31 PM
(Ducks, well aware of the high esteem many hold these balls in…)

We actually threw out all our DHS D40+ balls, a few 100 of them. A few were good, many were horrible duds. Might have been bad luck, but if so then bad luck in multiple production batches. Which guides me To distrusting QA, and life’s too short for that.

(Yes, I could have tried returning them and beg for refunds or replacement. Like I said, life’s too short for that.)

Well seems like you mighta got unlucky there. I will agree though that the quality of the D40 isn't the best like with the NP40 I've never had those white lines appearing or logo fading etc. At the same time though I have had issues where all 3 NP40s in the box cracked after just a few weeks of moderate usage. There's also the fact that if you lose one or step on one that's 3 bucks in the bin. Bottom line for me though is that I can get 50 D40s for less than 20 bucks so even if one does get cracked, it's not much of a biggie.