Breaking in a disc - Changing stability

Does anyone know why a disc changes stability over time?

I can understand disc flight changes with major deformations or other physical damage, but I am more inquiring about standard wear and tear.

Also, any tips to quickly break in a new/replacement disc to replace an old favorite?

I lost an old favorite disc the other day. I want to get the replacement to fill in the hole in my bag quickly. With tournaments starting, there is no time to keep throwing the disc and wait for it to slowly break in.

[J.C.]

throw it into a tree a bunch of times, or if you don't care about the edges of the disc, then a teepad. just do a normal backhand as hard as you can. if you throw it into a teepad you can smooth out the rough spots with sand paper

[Brad]

get a used disc from ebay, ask one of your friends if he has one laying around, or ask someone from discgolfersRus for help.

[jesse p. mccain]

throw it hard into chains the grippyer plastics will break in way faster on chain

[PUNJA]

Thanks for the comments.

Any ideas on the reason for the change in stability?

[Lotto]

www.discaroo.com look for used discs.

[Lotto]

J.C. said:

throw it into a tree a bunch of times, or if you don't care about the edges of the disc, then a teepad. just do a normal backhand as hard as you can. if you throw it into a teepad you can smooth out the rough spots with sand paper

um im pretty sure that will just ruin a disc. i wouldnt advise it.

just go out and play a few round with JUST that disc, that way you learn the disc really well AND you wear it in alittle. not just shaving plastic off of the bottom from railing it on the tee pad.....dumb idea.

[Red Line Disc Golf]

The reason a disc becomes less stable over time is because the plastic becomes less rigid.

One thing that I've heard of people doing to help speed up the process is adding heat to the disc to for long periods of time and then flex the disc and letting it cool (I in no way would attempt this on any of my own disc as I'm fairly certain that it will also cut down on the life of the disc). The method that was used on a star disc and the person (I wont name names) claimed to use was a heat gun passing it indirectly across the disc until it was about as hot as it would be if you left it in the window all day in the middle of a hot summer day and then they flexed it and repeated, this individual swears that they are able to break in a disc in only one day this way. Again I personally wouldn't try it but if you are willing to junk a disc if it turns badly then maybe this is your answer. I'm with every one else on this one the best way is to either buy used disc or play with them until they are broken in.

[Garrett Graham]

I flex my discs a lot when they are new. Don't know how much it helps but when they start flying right i stop flexing the rim

[Rubberband Man]

Taken from Aerobie's website regarding tuning the Epic:

Tuning discs, by bending them, works on long range drivers. I do not recommend it for shorter range discs. A typical long range driver has a rim about 3/4" wide, which is about the width of a penny. Our new Epic driver has a variable-width rim which varies in width from one inch to 1.6 inches (fig 3 below). The wider the disc's rim, the more it responds to tuning.

To decrease the stability of any driver, you simply bend it downward. This can be done either by just flexing it like a taco, or by working your hands gradually around while bending just the rim. I prefer this latter method because it doesn't leave the disc looking like it just encountered a freight train. Fig 1 shows a disc rim being bent downward to decrease stability. Start at one place on the disc and repeat this bend about every 45 degrees around it until you are back where you started.

And of course, to increase the stability, you simply bend the rim upward (fig 2).

What's Happening?

Downward bending reduces the height of the outer edge of the disc and that's what changes the flight. Upward bending increases the edge height. It's as simple as that.

Many players whom I've taught about tuning have worried that the disc won't hold its tune but I can assure you that your disc will retain its tune very well. I often measure the heights of disc edges with a special instrument that I made just for this purpose (fig 3 below). It's accurate to one half-thousandth of an inch and has proven that discs hold their tune indefinitely. This instrument has been useful to my disc research, but you don't need it to tune your own discs. Just go out to an open field and start bending and throwing.

Of course any disc, tuned or not, will become distorted if you leave it in a hot car with a pile of heavy stuff on it. So, if you're serious about accurate flights, you should store your discs properly without any pressure that might bend them.

Most players have noted that well-used discs tend to become less stable with time. It's often thought that dinged edges are the culprit. However I've deliberately dinged the edges of discs and observed no change in flight stability. Thus I think it's likely that the disc's edge has simply been bent downward from accumulated encounters with trees, rocks and other hard surfaces.

[Mike]

From what I learned in the plastics program where I am getting my degree. Plastic polymer has what they call "memory" in the sense that it will contract when the molecules are heated and de-stress. Different types of polymers have different "shrink rates" these are usually accounted for when the process is designed. This has a lot to do more with when a part is molded, the plastic is molten and injected at high pressure into a mold and then cooled at a set parameter to solidify the polymer into the desired shape. As the part cools in the mold it will actually shrink slightly, cooling times for different materials can vary and if the part is cooled too quickly, ejected from the mold too soon, the plastic can deform/destort or shrink unpredictably. This is why the same mold disc can have a different flight characteristic when made in a different run depending on the machine temperatures, ambient temperatures, and other process set up variables such as cooling time.

It is my belief that the polymer memory can be slightly related to the disc changing over time combined with the disc taking tree/rock/dirt hits. Those things seem to also de-stress the plastic over a long period of use, and quicker with the softer more pliable materials, eg. DX, Pro D, even Star and ESP as opposed to Champion or Z that are noticeably more ridgid.

In conclusion, I would have to say that the more a disc is de-stressed over time the more understable it will become. This can be you bending the plastic on purpose with your hands, a hammer (not recommended), trees (happen), dirt (happens), rocks (happen), teepads (sucks when that happens), heat (natural, but not a heatgun or leaving in a car trunk all day), even just power gripping every time you drive and flexing the disc slightly. Over time all of these factors add up and make your discs break in and flight characteristics change. This is the best explanation I can give you. Here is an example of shrink, and memory of plastic that one of my professors gave our class.
For a science experiment:
Take a (empty) 2 liter plastic soft drink bottle with the cap off.
Pre-heat your oven to 200*F.
Place said bottle on center oven rack.
Bake for 5-8 min.
Bottle will be about half the size it was when you started

[Jamie 'gr8rocshot' Ruane]

Mike said:

From what I learned in the plastics program where I am getting my degree. Plastic polymer has what they call "memory" in the sense that it will contract when the molecules are heated and de-stress. Different types of polymers have different "shrink rates" these are usually accounted for when the process is designed. This has a lot to do more with when a part is molded, the plastic is molten and injected at high pressure into a mold and then cooled at a set parameter to solidify the polymer into the desired shape. As the part cools in the mold it will actually shrink slightly, cooling times for different materials can vary and if the part is cooled too quickly, ejected from the mold too soon, the plastic can deform/destort or shrink unpredictably. This is why the same mold disc can have a different flight characteristic when made in a different run depending on the machine temperatures, ambient temperatures, and other process set up variables such as cooling time.

It is my belief that the polymer memory can be slightly related to the disc changing over time combined with the disc taking tree/rock/dirt hits. Those things seem to also de-stress the plastic over a long period of use, and quicker with the softer more pliable materials, eg. DX, Pro D, even Star and ESP as opposed to Champion or Z that are noticeably more ridgid.

In conclusion, I would have to say that the more a disc is de-stressed over time the more understable it will become. This can be you bending the plastic on purpose with your hands, a hammer (not recommended), trees (happen), dirt (happens), rocks (happen), teepads (sucks when that happens), heat (natural, but not a heatgun or leaving in a car trunk all day), even just power gripping every time you drive and flexing the disc slightly. Over time all of these factors add up and make your discs break in and flight characteristics change. This is the best explanation I can give you. Here is an example of shrink, and memory of plastic that one of my professors gave our class.
For a science experiment:
Take a (empty) 2 liter plastic soft drink bottle with the cap off.
Pre-heat your oven to 200*F.
Place said bottle on center oven rack.
Bake for 5-8 min.
Bottle will be about half the size it was when you started

Based on this and what I've heard about Disc Manufacturing ...regulating the temperture of the molten plastic is key in the weight range for each batch of discs... I believe if more heat is used, the plastic hardens less dense...thus being lighter.

Is that correct Mike? or do I have it backwards?


Anyway, I suppose you could toss your new plastic into the Dryer with a lower heat setting...and essentially launder or age the disc.....hmmmmm!!

Just don't let your wives catch you doing that!!! lol!

[Mike]

Jamie, I believe that could make sense, however I must say I am not familiar with the exact plastics that they use or exactly how they manipulate part weight with discs. Injection screw and barrel temperatures are crucial to any injection molding process, more heat will disperse the molecules further apart = less dense material = lighter part. I know I have also manipulated part weight in processing labs by adjusting the pack and fill settings on the machine. Obviously, you need to have a large enough shot size to fill the part out completely, too little and you can end up with sinks and voids in the part after cooling, but you can pack more material into a part than needed and add weight and density. It can depend on the exact material you use though and the shrink rate of that material.

Also, at 200*F the plastic bottle will not melt or stink up the oven in that short of a period of time. Put the bottle on a piece of aluminum foil if you are worried, but tell the wife it is crucial to you understanding something educational in the name of science. She'll have to understand then... right?