Interesting Failure of Inline Socket Casings - Page 1
Forum section: electronics / projects

author: sleemanj
author_rank: Super Contributor
timestamp: May 10, 2017, 12:08:45 am
content: Take a look at this, these are 3.5mm inline sockets. I had noticed as I've been packing them as sold that a few of the strain reliefs were broken off (of course I'd put that aside and send another one), anyway today I had a closer look.The plastic on these either was, or has become incredibly brittle, just touching the strain relief is enough to cause it to crumble into pieces, and merely rolling/squeezing the connector between my fingers will cause most of the case bodies to shatter also.Never seen anything like it before.Even more interesting is that looking at my import records, I think this batch was added to the stock 3 and a half years back, but it's only recently I've noticed it as a problem, which leads me to think that they have degraded over time rather than being an initial manufacturing issue.

author: james_s
author_rank: Super Contributor
timestamp: May 10, 2017, 12:43:17 am
content: It's not uncommon for plastic to do that over time as the plasticizers evaporate, but it shouldn't deteriorate so quickly. Exposure to things like ozone and UV will accelerate the deterioration but I think that's probably unlikely here. I suspect it's just poor quality material.

author: Audioguru
author_rank: Super Contributor
timestamp: May 10, 2017, 01:33:15 am
content: The plastic has too much rice flour in it. I would use Switchcraft if they make the socket. They do not use rice flour in anything they make.

author: Monkeh
author_rank: Super Contributor
timestamp: May 10, 2017, 01:43:04 am
content: I've had a few examples of this sort of crap, it takes a few years to go bad.I just avoid that style entirely now. They're pretty universally garbage anyway.

author: jonovid
author_rank: Super Contributor
timestamp: May 10, 2017, 04:05:51 am
content: Quoteit seems like plastic decomposition times are exaggerated by the environmental movement. saying it will take 100s of years.but plastic breakdown is really worse than we are told.plastics used in aircraft are considered to be the best.however Air Crash Investigation on national geographic did show how plastic in aircraft wire insulation did start to breakdown in just 25 yrs.leading to aircraft crash's & near disasters from around the globe. the wire insulation became brittle & cracked.looks like your 3.5 mm stereo line sockets are poor or inferior quality plastic or just sat out side in the chinese sun light for too long.I have had mixed results with chinese plastics. a way to preserve plastics plasticizers is to keep them in sealed containers,& out of the sun, so the plastic will not dry out as much over time.

author: rdl
author_rank: Super Contributor
timestamp: May 10, 2017, 04:38:15 am
content: A plasticizer that evaporates is not much of a plasticizer. Most of the ones I've had experience with are essentially non-volatile under the conditions they are intended to be used. Also, many types of plastic do not even require plasticizers. This particular instance seems as if it's most likely a bad batch of plastic. Probably just sloppy manufacturing followed by little if any QC testing.

author: Bud
author_rank: Super Contributor
timestamp: May 10, 2017, 04:52:57 am
content: Was it exposed to UV light perhaps?

author: Monkeh
author_rank: Super Contributor
timestamp: May 10, 2017, 04:54:04 am
content: Quote from: Bud on May 10, 2017, 04:52:57 amSome of my examples went bad inside a drawer. It's not UV.

author: Unknown
author_rank: Unknown
timestamp: May 10, 2017, 05:11:08 am
content: Quote from: sleemanj on May 10, 2017, 12:08:45 amDirect from China, or Jaycar / Electus?Bought some of those from Jaycar late last year - when I went to use them early this year they'd gone like that while sitting in a cardboard box in the cupboard. Next time I was passing through there I noticed about half the tray on the shelf were disintegrating.At least for 1-off quantities, decent name-brand (Lumberg / Shurter) ones from E14 work out the same/cheaper than Jaycar anyway.

author: Monkeh
author_rank: Super Contributor
timestamp: May 10, 2017, 05:15:32 am
content: Farnell sell some Lumberg DC plugs at least under Multicomp. For TS/TRS they stock Rean, which are reasonable (I seem to have worn the nickel off one here though).

author: james_s
author_rank: Super Contributor
timestamp: May 10, 2017, 07:59:51 am
content: Quote from: rdl on May 10, 2017, 04:38:15 amI've sure dealt with a lot of automotive trim on older cars that turns hard and brittle and/or shrinks with age and exposure to UV. Whatever happens to the plasticizer it goes away, this gets to be a real problem by the time the car is 20-30 years old. I've found that a soak in brake fluid or wintergreen oil will soften and revitalize it, for a while, but eventually it gets hard again.I also had an issue with engine wiring harnesses, supposedly they were made for a few years with insulation that is biodegradable. Well that's great except after being exposed to engine heat the insulation degraded and crumbled to dust while I was still driving the car. Actually looked a lot like the deterioration of these connectors.Rubber bands dry out and do the same thing, especially when exposed to sunlight. It's entirely possible the plastic in those connector shells is actually a type of rubber.

author: BravoV
author_rank: Super Contributor
timestamp: May 10, 2017, 08:50:37 am
content: Some plastic just suck like this bad flaking connector, and its slowly degrades turning into very brittle POS.

author: sleemanj
author_rank: Super Contributor
timestamp: May 10, 2017, 10:08:51 am
content: Quote from: Tac Eht Xilef on May 10, 2017, 05:11:08 amDirect from China. It's interesting that it seems to be limited specifically to these 3.5mm sockets, I have drawers full of 5.5 barrel plugs, sockets and 3.5 plugs, of that usual cheap plastic casing design and none of them have disintegrated like these.Not UV exposed, sitting in drawers in the dark corner of the office I call my stock storage area.

author: Ian.M
author_rank: Super Contributor
timestamp: May 10, 2017, 10:12:05 am
content: You are lucky the casings didn't turn into black goo and start eating everything plastic they were in contact with. Of the two common failure modes for low grade plastics I much prefer brittle to goo - it usually causes less collateral damage.

author: madires
author_rank: Super Contributor
timestamp: May 10, 2017, 10:19:25 am
content: I got that problem too with some cheap 3.5mm TSRs and barrel connectors. After about two years the plastic simply breaks. Sunlight might speed up that process. I'd guess it's very cheap and bad plastic. BTW, I've got them from a local well known shop and about one third of the cheap plugs are affected. My fix is to replace the broken casings with two layers of heat shrink tubing.

author: james_s
author_rank: Super Contributor
timestamp: May 10, 2017, 03:44:14 pm
content: Quote from: Ian.M on May 10, 2017, 10:12:05 amI've seen that where two materials were in contact with each other and both turned to goo at the contact point. I've seen it happen with power cords wrapped around plastic cased devices, and I've also had it happen with rolls of two different types of tape that turned to goo at the points where they touched each other. I'd be curious to know more about the chemistry at play there.

author: rdl
author_rank: Super Contributor
timestamp: May 10, 2017, 04:45:10 pm
content: Quote from: james_s on May 10, 2017, 03:44:14 pmIf either or both materials are vinyl based, a bad case of plasticizer migration would be my first guess.

author: Neomys Sapiens
author_rank: Super Contributor
timestamp: May 12, 2017, 12:47:02 am
content: I ordered clip-on ferrites from Wuerth recently and they came in metallized sealed bags. Also, there was a label telling me to leave them sealed. I looked for an answer and found out that it is not about the ferrites but the plastic snap-on part. They claim, that if dried out, it might not perform properly. I called their applications engineer and guess what he told me: it's the greenies again! The limits and controls extend to such a lot of substances now that they are not able to make the commercial grade plastic parts as durable as they once were.

author: 0b01010011
author_rank: Regular Contributor
timestamp: May 12, 2017, 02:13:09 am
content: this is a bit reminiscent of the Hammond Organ foam problem!

author: amyk
author_rank: Super Contributor
timestamp: May 12, 2017, 02:17:08 am
content: Quote from: sleemanj on May 10, 2017, 10:08:51 amThey could've been exposed to some other gases (ozone comes to mind first) which can attack plastics --- perhaps even the outgassing from some other components in the vicinity.

author: rdl
author_rank: Super Contributor
timestamp: May 12, 2017, 03:25:08 am
content: Quote from: Neomys Sapiens on May 12, 2017, 12:47:02 amI'd be willing to bet that cost is the real problem. I don't believe for a second that suitable plastic of reasonable quality is no longer able to be made.

author: BravoV
author_rank: Super Contributor
timestamp: May 12, 2017, 03:35:51 am
content: Quote from: Neomys Sapiens on May 12, 2017, 12:47:02 amIts so hard not to suspect all of these is a planned obsolescence in disguise at global scale, especially seeing big names as the main raw plastic material supplier throughout the world like Dow Chemical, Exxon, BASF, Chevron Philips and etc.