Author Topic: Strange reaction between cable and plastic box  (Read 3944 times)

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Offline ferdieCX

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Strange reaction between cable and plastic box
« on: October 15, 2018, 08:34:06 pm »
Hi, I am a little surprised:

About 8 years ago, I bought one of those cheap packs with 10 double alligator test leads.
I have not used most of them in the last months and yesterday I wanted to take them out of the small yellow box in the drawer.
To my surprise, they tended to remain like glued to the box. The cables have somehow reacted with the plastic material of the box affecting it, as you can see in the pictures.
The other boxes in the drawer doesn't seem to be affected.
Both the yellow box and the cables where bought in Germany.

Has something like that happened to anyone of you ?
 

Offline PointyOintment

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Re: Strange reaction between cable and plastic box
« Reply #1 on: October 15, 2018, 08:41:40 pm »
Excessive plasticizers in the wire insulation (which is usually made of heavily plasticized PVC)?

Also, you're still using an Apple (Pro) Mouse? I haven't seen one of those in years.
 
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Offline ferdieCX

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Re: Strange reaction between cable and plastic box
« Reply #2 on: October 15, 2018, 08:49:12 pm »
Also, you're still using an Apple (Pro) Mouse? I haven't seen one of those in years.

Yes, it is an old Apple Mouse, the normal white version
I usually run a CentOS box, but I sometimes use my old iBook G4 when I need a  laptop

Thank you very much for the explanation
« Last Edit: October 15, 2018, 08:53:17 pm by ferdieCX »
 

Offline PointyOintment

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Re: Strange reaction between cable and plastic box
« Reply #3 on: October 15, 2018, 09:01:34 pm »
I think I've seen this effect before with cheap jumper cables, but I forget exactly where. Those grooves in the box looked quite familiar, somehow. … Oh! I remember: I have a set of breadboard jumper wires, and stored it together with some of the cheap alligator jumper cables. The clear plastic box got those grooves in it.

Edit: I actually have the older version of those alligator cables—I don't know if SparkFun's current version has the same issue.
« Last Edit: October 15, 2018, 09:07:42 pm by PointyOintment »
 

Online Andy Watson

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Re: Strange reaction between cable and plastic box
« Reply #4 on: October 15, 2018, 09:41:52 pm »
This:
Excessive plasticizers in the wire insulation (which is usually made of heavily plasticized PVC)?

I have not seen wires with this problem but those PVC "hoods" for miniature croc-clips definitely do decompose - and eat into almost any plastic that they contact.

And watch out for stick-on feet too.
 
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Online tooki

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Re: Strange reaction between cable and plastic box
« Reply #5 on: October 15, 2018, 09:58:55 pm »
As you can tell, it’s not such a strange reaction, actually!!

One more culprit to watch out for: erasers! Many of them are also highly plasticized PVC (often just called “vinyl erasers”), and they’ll do the same thing. Not uncommon to find a pen cap gone weird after laying in contact with a vinyl eraser for a year or two. I’ve even seen them outright fuse together!
 

Offline sparx

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Re: Strange reaction between cable and plastic box
« Reply #6 on: October 15, 2018, 11:36:59 pm »
Had a mains appliance from eBay (China), the mains IEC lead had welded itself to the polystyrene packaging to the point I was scraping polystyrene off the mains lead.

This happens surprisingly a lot - I also bought a (cheapish) neoprene laptop sleeve that arrived stinking to high heaven of chemicals. One wash in the washing machine later, it was a lot more usable.
 

Offline coppercone2

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Re: Strange reaction between cable and plastic box
« Reply #7 on: October 15, 2018, 11:47:36 pm »
where are our chinese state sponsored super powers?
 

Offline bsfeechannel

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Re: Strange reaction between cable and plastic box
« Reply #8 on: October 16, 2018, 12:03:39 am »
One more culprit to watch out for: erasers! Many of them are also highly plasticized PVC (often just called “vinyl erasers”), and they’ll do the same thing. Not uncommon to find a pen cap gone weird after laying in contact with a vinyl eraser for a year or two. I’ve even seen them outright fuse together!

Hmm. That probably explains what happened when I left one of those erasers unheeded in an organizer for some months.

 

Online tooki

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Re: Strange reaction between cable and plastic box
« Reply #9 on: October 16, 2018, 12:11:35 am »
Yep, absolutely! I’m sure the plastic bin in the OP’s photo would have had the same reaction.
 

Offline blueskull

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Re: Strange reaction between cable and plastic box
« Reply #10 on: October 16, 2018, 12:40:24 am »
where are our chinese state sponsored super powers?

Did you mean Russia? Or did you mean US?
 

Online Monkeh

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Re: Strange reaction between cable and plastic box
« Reply #11 on: October 16, 2018, 01:01:40 am »
Had a mains appliance from eBay (China), the mains IEC lead had welded itself to the polystyrene packaging to the point I was scraping polystyrene off the mains lead.

This happens surprisingly a lot - I also bought a (cheapish) neoprene laptop sleeve that arrived stinking to high heaven of chemicals. One wash in the washing machine later, it was a lot more usable.

PS is well known for leeching the plasticizer from PVC violently. It's why they bag the cables!
 

Online james_s

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Re: Strange reaction between cable and plastic box
« Reply #12 on: October 16, 2018, 01:19:13 am »
I've seen the same thing with power cords wrapped around a device made of certain types of plastic. I also had it happen when I left two rolls of different kinds of tape stacked on top of each other.
 

Offline Gary350z

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Re: Strange reaction between cable and plastic box
« Reply #13 on: October 16, 2018, 02:29:22 am »
I have seen this many times.
Be careful with any type of rubbery material in contact with plastic.
This can also happen with polyurethane finishes on cabinets or tables.

Examples rubbery materials I've had problems with:
Erasers, model car tires, rubber grommets, rubber chassis feet, power cords, alligator clip leads.
 
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Offline rdl

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Re: Strange reaction between cable and plastic box
« Reply #14 on: October 16, 2018, 12:23:24 pm »
In the paint business we call this plasticizer migration. The best plasticizers are usually also good solvents for the substance they are plasticizing. If the plasticized item comes in contact with a similar material, the plasticizer can leech out or migrate from one to the other. Since the plasticizer is also a solvent to some degree, swelling or deformation will occur. Highly polymerized or crosslinked plastics such as polyethylene will be resistant to this effect, while "thermoplastics" such as ABS or styrene are easily damaged.
 
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Offline coppercone2

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Re: Strange reaction between cable and plastic box
« Reply #15 on: October 16, 2018, 12:44:29 pm »
is this actually normal with properly made plastics?

I don't think I ever saw this kind of weird welding effect, other then then wires are sometimes twisted into knots as strain relief (but its in stuff thats like 40 years old).
 

Offline TerraHertz

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Re: Strange reaction between cable and plastic box
« Reply #16 on: October 16, 2018, 01:46:14 pm »
PS is well known for leeching the plasticizer from PVC violently. It's why they bag the cables!

Back to front. Expanded PS foam doesn't change the diffusion rate of plasticizers out of PVC. It just has a very small amount of PS (thin foam cell walls) to melt, so the plasticizers have a far more dramatic effect on the PS foam.

Plasticizers are *everywhere*. A chemist friend of mine mentioned it's virtually impossible to prepare samples for gas or liquid chromatography, without them having plasticizers contamination.
And people wonder why there is a cancer epidemic.

The diffusing plasticizers effect I hate most, is the way photocopy toner on pages near the front and back covers of PVC ring binders, gets softened and transferred between paper surfaces. Also sticking the pages together.

Second most disgusting effect, is the way some types of aged cable insulation accumulates a tacky surface scum of concentrated plasticizers, which then becomes a dirt sponge, and also transfers to your skin if you handle the cables. Where it does what plasticizers are designed to do - dissolve into organic material and disrupt it's prior structure. Your cells in this case.

(ITT, I learned that web spell checkers consider the word plasticizer (singular) to be invalid.)
« Last Edit: October 16, 2018, 01:48:11 pm by TerraHertz »
Collecting old scopes, logic analyzers, and unfinished projects. http://everist.org
 
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Offline ferdieCX

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Re: Strange reaction between cable and plastic box
« Reply #17 on: October 16, 2018, 04:33:18 pm »
Thank you very much to all of you, this thread has been very informative.
I suppose, that self build test cables using silicon cable and test hooks with ABS body are today the only safe option.

is this actually normal with properly made plastics?
I don't know, but I still have some self built test cables made 40 years ago when I was a student.
I never had any issue with them, but the alligators are made in Japan and the cable itself is made in Uruguay.
« Last Edit: October 16, 2018, 04:36:07 pm by ferdieCX »
 

Offline blueskull

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Re: Strange reaction between cable and plastic box
« Reply #18 on: October 16, 2018, 04:36:08 pm »
is this actually normal with properly made plastics?

I don't think I ever saw this kind of weird welding effect, other then then wires are sometimes twisted into knots as strain relief (but its in stuff thats like 40 years old).

I had a Tek differential probe having this issue. The rubberized probe head decomposed and left oil and a nasty smell.
The cable still held well, but I decided to return it. I'm not gambling with $300 worth of used crumbled plastic.
 

Online tooki

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Re: Strange reaction between cable and plastic box
« Reply #19 on: October 16, 2018, 04:58:39 pm »
PS is well known for leeching the plasticizer from PVC violently. It's why they bag the cables!

Back to front. Expanded PS foam doesn't change the diffusion rate of plasticizers out of PVC. It just has a very small amount of PS (thin foam cell walls) to melt, so the plasticizers have a far more dramatic effect on the PS foam.

Plasticizers are *everywhere*. A chemist friend of mine mentioned it's virtually impossible to prepare samples for gas or liquid chromatography, without them having plasticizers contamination.
And people wonder why there is a cancer epidemic.

The diffusing plasticizers effect I hate most, is the way photocopy toner on pages near the front and back covers of PVC ring binders, gets softened and transferred between paper surfaces. Also sticking the pages together.

Second most disgusting effect, is the way some types of aged cable insulation accumulates a tacky surface scum of concentrated plasticizers, which then becomes a dirt sponge, and also transfers to your skin if you handle the cables. Where it does what plasticizers are designed to do - dissolve into organic material and disrupt it's prior structure. Your cells in this case.

(ITT, I learned that web spell checkers consider the word plasticizer (singular) to be invalid.)
I remember seeing YouTube videos about some mains wire that, over the years, would leach so much plasticizer that it would drip down the conduit and sometimes drip out of wall sockets/switches!! It would corrode the copper on the way, making it green. I think it was on JW’s channel, so I think UK, but I could be wrong.
 

Offline calexanian

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Re: Strange reaction between cable and plastic box
« Reply #20 on: October 16, 2018, 06:08:09 pm »
Some plastics are incompatible for contact with others over time. I just tried searching for it and could not find it, but I used to have a chart with various plastic to plastic compatibility comments. Some combinations would cause that effect, mostly involving ABS, or PVC as one of the components.
Charles Alexanian
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Offline glarsson

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Re: Strange reaction between cable and plastic box
« Reply #21 on: October 16, 2018, 06:19:56 pm »
Incompatible plastics can be expensive. About 20 years ago a subcontractor substituted a cheap soft plastic part mounted on a PCB. After just a few years the reaction between the plastic part and the conformal coating allowed moisture to penetrate the conformal coating leading to failures of the engine control unit. The recall involved a huge number of vehicles all over the globe.
 

Online SeanB

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Re: Strange reaction between cable and plastic box
« Reply #22 on: October 16, 2018, 06:37:42 pm »
I remember seeing YouTube videos about some mains wire that, over the years, would leach so much plasticizer that it would drip down the conduit and sometimes drip out of wall sockets/switches!! It would corrode the copper on the way, making it green. I think it was on JW’s channel, so I think UK, but I could be wrong.

That was the early generations of PVC wire, with BPA plasticiser that would react with the copper and make the green goo in the walls. Generally any PVC electrical wire made between around 1960 and 2000 would have that occur, only later on did the amount of plasticiser get reduced and replaced with a non BPA based one. Bisophenol A is a known carcinogen, which is why you find so many baby bottles labelled as BPA free plastic, and why so many are made from PET these days and not PVC. A lot of older plasticware however is PVC with BPA in it as plasticiser though, and it is oil soluble, and leaches out into the foodstuffs stored in it.
 

Offline coppercone2

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Re: Strange reaction between cable and plastic box
« Reply #23 on: October 16, 2018, 08:32:25 pm »
life in plastic, its fantastic

« Last Edit: October 16, 2018, 08:35:49 pm by coppercone2 »
 

Online Monkeh

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Re: Strange reaction between cable and plastic box
« Reply #24 on: October 16, 2018, 11:07:39 pm »
PS is well known for leeching the plasticizer from PVC violently. It's why they bag the cables!

Back to front. Expanded PS foam doesn't change the diffusion rate of plasticizers out of PVC. It just has a very small amount of PS (thin foam cell walls) to melt, so the plasticizers have a far more dramatic effect on the PS foam.

Plasticizers are *everywhere*. A chemist friend of mine mentioned it's virtually impossible to prepare samples for gas or liquid chromatography, without them having plasticizers contamination.
And people wonder why there is a cancer epidemic.

The diffusing plasticizers effect I hate most, is the way photocopy toner on pages near the front and back covers of PVC ring binders, gets softened and transferred between paper surfaces. Also sticking the pages together.

Second most disgusting effect, is the way some types of aged cable insulation accumulates a tacky surface scum of concentrated plasticizers, which then becomes a dirt sponge, and also transfers to your skin if you handle the cables. Where it does what plasticizers are designed to do - dissolve into organic material and disrupt it's prior structure. Your cells in this case.

(ITT, I learned that web spell checkers consider the word plasticizer (singular) to be invalid.)
I remember seeing YouTube videos about some mains wire that, over the years, would leach so much plasticizer that it would drip down the conduit and sometimes drip out of wall sockets/switches!! It would corrode the copper on the way, making it green. I think it was on JW’s channel, so I think UK, but I could be wrong.

Oh yes, I've seen that stuff. Some of the original wiring in my house has done that to a very limited degree over the last 40 years or so. Come across a few places with green goo filled junction boxes.
 
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