Plastic rot on contacts or what is it?

[Dekatron42]

I've had a few Nixie clock circuit boards in storage in a cardboard box in my apartment for a few years now and today after unpacking them I could see some white "moss" like rot on them on three different Nixie clocks. They have been lying wrapped in bubble plastic inside a DHL cardboard box and I've never seen anything like this before - does anyone here know about this and why it has appeared on these contacts, nothing else seems affected and the boards work just as they should?

I'll desolder all conacts and fit new as soon as I have them in the mail.

/Martin

[Dekatron42]

Problem attaching photos.....

[Dekatron42]

Problem attaching photos.....

On Thursday 24 October 2024 at 22:37:18 UTC+2 Dekatron42 wrote:

Problem attaching photos.....

[Dekatron42]

Problem attaching photos.....

[Dekatron42]

None of the capacitors seems to have leaked nor does any other component seem to be affected and nothing else looks corroded but there are some small droplets on one of the power connectors.

/Martin

[Mac Doktor]

On Oct 24, 2024, at 4:40 PM, Dekatron42 <martin....@gmail.com> wrote:

None of the capacitors seems to have leaked nor does any other component seem to be affected and nothing else looks corroded but there are some small droplets on one of the power connectors.

Looks like elasticizer leaching out of the plastic but I've never seen it happen to something this new.

Terry Bowman, KA4HJH
"The Mac Doctor"

https://www.astarcloseup.com

"If only you could see what I've seen with your eyes."—Roy Batty, Blade Runner

[Nicholas Stock]

As they're in a sealed container, any outgassing from components/PCB etc may react with plastics? Just a guess....

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[Neil QQ]

Terry, I believe you are correct about the plasticizer, or some such outgassing.  At my work we ran into something similar with a big last-time-buy order for connectors.  They looked exactly like your pictures.  As I recall, the key to "prevention" is to allow for air circulation when stored, i.e. not stored in plastic bags.  The stuff was declared "not deleterious to the functional aspects of the connector".  They were cleaned with alcohol (don't recall which type/concentration) and placed back into stock. 

[Terry S]

There is also a rather strange fungus that likes to grow on certain plastics. Ask anyone who has ever collected old radios..

It wipes right off and take a long time to return.

[Alex]

I have seen this a few times, often on stored items like you say. My jam jar of reclaimed connectors comes to mind. I put it down to flux crystals left after hand soldering. Flux is weird stuff and reacts oddly with many things over time, especially the weird modern mix of fluxes and lead free solders. Good clean with a stiff painbrush and some IPA and you'll be fine I think!

[Neil QQ]

I'm restoring an old wire recorder now and see minor white-ish film on some of the plastic parts.  Curiously the Bakelite items look like brand new.  Alcohol easily removes the film.  

There are lots of internet posts about older Xcelite plastic tool handles developing a white film and smelling like vomit.  I have two, identical PS-120 nut driver sets bought at the same time in the 70's.  One set I use all the time.  The other was squirrelled away, forgotten, in a box.  The often used one is fine.  When I recently re-discovered the forgotten one I about vomited when the case was opened.  Every plastic surface, except for the case itself, was covered in the powdery, white, foul-smelling stuff.  Alcohol easily removed the film and pretty much the smell too.  The frequently used set has no signs or smells of the white stuff.  

[Mac Doktor]

On Oct 26, 2024, at 10:26 AM, Neil QQ <nei...@gmail.com> wrote:

I'm restoring an old wire recorder now and see minor white-ish film on some of the plastic parts.  Curiously the Bakelite items look like brand new.  Alcohol easily removes the film.  

This REALLY sounds like elasticizer leaching out. Fire retardant chemicals exacerbate the problem. The plastic parts of computers from the '90s are now very stiff and snap like a twig when you try to open something. I collect antique Christmas lights and some of the plastic parts from the late '40s and early '50s have completely disintegrated. Gone. Some brands of bubble lights from that period just crumble into powder. Regarde:

"To add to NOMA's troubles, one of their sets of bubble lights was accused of starting a fire, which tragically involved a fatality. NOMA and most other bubble light manufacturers immediately added a fire retardant chemical to their plastic. NOMA outfits that include this chemical are clearly and boldly marked with the UL approval information on the front cover of the box (see picture above, third from left). The chemical caused the premature breakdown of the plastic in the lights, making them useless within a few years. Lights showing this disintegration are shrunken and severely distorted (fourth picture from left), and are often found with a whitish coating that is often erroneously attributed to spray snow or heat damage. The lights illustrated above show the damage that was caused by the flame retardant. Note that since these lights are from 1949 and later, they do not contain the glass slug. After a few years, it was determined that the NOMA bubble light set was not the cause of the fire, and the chemical was no longer used in the manufacture of the lights. The picture to the far right is of an ad NOMA strategically placed in the 1949 edition of the Fire Engineering Magazine, explaining the use of the new chemical.

"Another victim of the chemically-impregnated plastic, NOMA Sno-Flake Gems were sold in 1949-1951. Few examples of the lights themselves survive. Those that do will likely be showing signs of deterioration from the fire retardant additive."

See the bottom of this page:

http://oldchristmastreelights.com/1946_1950_4.htm

It's been a while since this was written and it's only gotten worse in the meantime. I have some items I purchased in the Mid-'90s that suddenly fell apart a few years later. I have the Santa and the candle. He's completely gone and the flame on the candle is like sugar. It crumbles into a powder when you touch it.

Bakelite doesn't have this problem. Xmas light sockets from almost a hundred years ago look new. 

Add bubble tubes to your collection...

There are lots of internet posts about older Xcelite plastic tool handles developing a white film and smelling like vomit.

Yep. I have a laptop from around 2000 with the stinkiest keyboard in existence.

Has the knob on your gearshift gotten sticky yet? I once heard that switching to a chrome plated metal knob adds five horsepower.

Terry Bowman, KA4HJH
"The Mac Doctor"

https://www.astarcloseup.com

"I’ve seen things you people wouldn’t believe. Attack ships on fire off the shoulder of Orion. I watched c-beams glitter in the dark near Tannhäuser Gate. 

"All those moments will be lost in time like tears in the rain."— Roy Batty, Blade Runner

[Kevin A.]

https://www.motortrend.com/news/bleech-whats-that-smell-coming-from-my-toolbox/

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