Author Topic: How do you remove stress marks?  (Read 5275 times)

Offline playmofire

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How do you remove stress marks?
« on: January 04, 2006, 08:43:29 »
Or may be the question is "Can you remove stress marks?"

I had to disassemble a custom late on in building it and after I got everything back together noticed a stress mark in the grey plastic chassis.  I could recustom the chassis I suppose, but that was quite a job in itself.  So anyone any ideas on removing stress marks?

I've tried polishing and gently sanding and think it made an improvement, but I'm not sure.

I'm wondering about heating the plastic gently with a hair dryer.

Any thoughts, folks? :eh?:
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Offline Little Jo

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Re: How do you remove stress marks?
« Reply #1 on: January 04, 2006, 09:57:01 »
Hm, to be honest, I actually do not understand what went wrong  ??? (maybe my English is too bad  :() ...

Offline Sylvia

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Re: How do you remove stress marks?
« Reply #2 on: January 04, 2006, 09:59:24 »
I think Gordon means those white marks or lines you get if a piece of inflexible Playmo is bent too far.
I'm sorry, but I don't have any clues on how to remove these either. :(

Offline Little Jo

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Re: How do you remove stress marks?
« Reply #3 on: January 04, 2006, 11:08:57 »
Ah, ok. Thanky, Sylvia, for the explaination. (Yes, I can remember, I have such faults too) -- Hm, I'm not sure if these can be removed at all, because I got the impression that these stress marks are physical deformations within the material ("over-bending").  So, I think there would be no other solution than covering them.

Offline Tim_w

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Re: How do you remove stress marks?
« Reply #4 on: January 04, 2006, 17:32:08 »
Hello  Gordon

I don't think there is a solution to this problem either unfortunately. It all depends on how much the plastic was stressed because stress marks can penetrate deep into the plastic. An option you allready tried is sanding but as you found that would probably only remove a small amount off the surface. In the end if it effects the custom and you really want to do something about it the only solution would be to repaint the whole chassis.

Kindest regards  Tim

(28/5/03/850)

Offline playmofire

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Re: How do you remove stress marks?
« Reply #5 on: January 04, 2006, 17:52:57 »
Thanks for the replies, folks.

Sanding lightly has helped a bit and on another site there was mention of heating the plastic and then reshaping it gently.  I shall try this with a hair dryer.  (The side of the chassis has bowed out very slighty, though you need to look closely from above to see this.)

If necessary, I will look into painting part or all of the chassis. :(
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Offline Psyche

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Re: How do you remove stress marks?
« Reply #6 on: January 04, 2006, 23:27:36 »
Thanks for the replies, folks.

Sanding lightly has helped a bit and on another site there was mention of heating the plastic and then reshaping it gently.  I shall try this with a hair dryer.  (The side of the chassis has bowed out very slighty, though you need to look closely from above to see this.)

If necessary, I will look into painting part or all of the chassis. :(

Heating and reshaping can help a lot depending on the sharp of the item and severity of the stess mark. I heat gun (used for many crafts) used at a distance is more effective than a blow dryer (and much faster.) But still, you can only do so much.

Painting may indeed help.
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Offline matchboxluc

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Re: How do you remove stress marks?
« Reply #7 on: January 05, 2006, 16:05:03 »
A stress mark is in fact many tiny cracks in the plastic concentrated in a small area. These cracks are dispersing the colour of the plastic and weaken it, making it look lighter. Heating it may fuse the cracks together again, thus bringing back the colour.
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Offline playmofire

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Re: How do you remove stress marks?
« Reply #8 on: January 05, 2006, 17:19:01 »
The hair dryer approach seems to have made a slight difference.

I'm loath to try too much heat in case I damage the bodywork itself.  (Removing and replacing the body was what caused the stress marks.)

I may try holding a hot soldering iron close to.
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Offline Little Jo

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Re: How do you remove stress marks?
« Reply #9 on: January 05, 2006, 17:39:01 »
I'm really curious about your results. (I hope it works)