Question regarding Stress Marks

Discussion in 'Transformers Toy Discussion' started by kezza1986, Jul 11, 2012.

  1. kezza1986

    kezza1986 Well-Known Member

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    Hello everyone,

    I've been a TF collector for many many years now, but one thing thats always concerned me is stress marks. I don't really understand them.

    I've bought several figures where they've had stress marks right out of the packaging and some which have just appeared out of every day play/transforming. Are these cracks within the plastic, or just areas that have become weaker? And will stress marks eventually lead to cracking of the plastic?

    I have Fall of Cybertron Generations Deluxe Jazz in hand at the moment. The rear of the car is comprised of two side panels pegging into the main body. The pegs are quite short and fat, so no real danger of breakage there. The hole for the peg on the side panels however, have been moulded too tight. In order to get the figure to transform correctly, i've had to apply some force to get the panels flush. The hole now has several stress marks around it, as its been stretched by the peg. At the moment, everything is fine. My concern though is that with repeated transformations, the hole will crack and then it won't have any hold at all, meaning it wont hold together.

    So can I ask, are stress marks something to worry about? And can anyone offer any advice about how they deal with stress marks? I know ultimately its nothing to lose sleep over as they're just toys. But, when you've spent a lot of money on a product, you want it to be robust.

    Sorry for the essay, thanks for reading!
     
  2. Aernaroth

    Aernaroth <b><font color=blue>I voted for Super_Megatron and Veteran

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    neither. Stress marks are areas where the plastic has become deformed. So it's either been stretched or bent, and was elastic enough to move back into more or less the same shape as before. What you're seeing is segments of the plastic network that were deformed beyond their elastic limit (or that couldn't go back to their original shape).

    If continued stress is applied to the same region over and over, yes, stress marks can be where fracture occurs. They do not necessarily represent a weakening of the plastic, but can be related to weakening effects.

    You can "anneal" out stress marks in some cases using heat, but it depends on the plastic, and how stressed it is. It can be difficult.

    If you're stressing out the hole, and constantly deforming and forcing it so it has developed stress marks, yes, this could lead to breakage or warping over time and repeated use.
     
  3. Fallout

    Fallout Well-Known Member

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    as far as i know, there's no permanent way to fix the stress. you can use heart to get the marks out but the stress is still there.
     
  4. kezza1986

    kezza1986 Well-Known Member

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    Thanks for the replies.

    If the plastic hole has been stretched out and formed stress marks, will it warp back to its original position and be stretched out each and every time? Or will it eventually stay there and retain the same position?

    I appreciate it'll differ on a case by case basis; I'm just trying to work out whether its safe to continue messing around with the figure or whether I should confine him to "display only"
     
  5. Fallout

    Fallout Well-Known Member

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    depends on the plastic; most will stay in their place. i don't own jazz nor do i plan to. what kind of feel does the plastic have to it? kind of a hard rubber?
     
  6. Aernaroth

    Aernaroth <b><font color=blue>I voted for Super_Megatron and Veteran

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    Depends on how much you're deforming it, and the properties of the material. If you're seeing stress marks? I suspect you've already gone past elastic deformation (where it'll go back to it's original shape, like a rubber band) and into plastic deformation, where it won't (like pulling taffy. Actually, go pull some taffy and see if that doesn't help you understand stress marks a little better. Then eat the delicious stretched taffy).

    So if you're doing plastic deformation (or at least parts of the hole are being plastically deformed), then it will warp more and more each time you further deform it. If there is a work hardening property in the plastic (there usually isn't), it may become more resistant to deformation the more you warp it. I suspect it'll get worse and worse though, however incrementally. Could be a long time before it causes problems other than the visible marks, though. This is a general case, I'm not that familiar with this particular figure, so I can't say for certain what kind of plastic he has or how it will behave.
     
  7. LCDR Blindside

    LCDR Blindside Banned

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    Delicious Science with Aenaroth.
     
  8. Aernaroth

    Aernaroth <b><font color=blue>I voted for Super_Megatron and Veteran

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    Gummy Bears may be a better simulation of the effect, now that I think of it.
     
  9. kezza1986

    kezza1986 Well-Known Member

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    Excellent, thank you Aernaroth; everyone.

    I think seeing as the peg goes in all the way flush now, it should be fine. It wont be able to stretch/deform any further.

    I'll bear all of this in mind though for any future figures!
     
  10. Brooticus

    Brooticus "You bred Raptors?"

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    For future reference, some say the carful use of a hair-dryer will eradicate any stressmarks that may have presented themselves, but I had great success recently with freshly boiled water (straight from the kettle), which could be viewed as a more controlled application of heat.

    My Arms Micron Breakdown, as great as he is, gained some stress marks around the AM ports when I tried to attach some weapons. It seems some of the peg-holes are a tad too small for AM Partners! See below:

    [​IMG]

    After a careful (and sustained) pouring of boiled water, I got those pesky marks right out!:

    [​IMG]

    Use caution though if trying this. Obviously, boiled water is involved, but I don't know how this method affects other plastic types either.
     

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