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 Post subject: Leaky goo from Micamold capacitors
PostPosted: May Wed 29, 2019 7:43 pm 
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Well I started the recap on my Magnavox Wedgewood chassis and already found some leaky Micamold capacitors. Anyone know what this goo is that's leaking from the Micamolds? It seems like some type of oil.


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 Post subject: Re: Leaky goo from Micamold capacitors
PostPosted: May Wed 29, 2019 7:55 pm 
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Those are paper inside, and they are likely impregnated with oil. They are always bad.

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 Post subject: Re: Leaky goo from Micamold capacitors
PostPosted: May Wed 29, 2019 11:58 pm 
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Restuff them...
viewtopic.php?p=2413271#p2413271

Greg.


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 Post subject: Re: Leaky goo from Micamold capacitors
PostPosted: May Thu 30, 2019 12:57 am 
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Nope, I'm getting the nasty things out of there. Orange drops going in their place.


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 Post subject: Re: Leaky goo from Micamold capacitors
PostPosted: May Thu 30, 2019 1:05 am 
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1988bluebird wrote:
Nope, I'm getting the nasty things out of there. Orange drops going in their place.
Orange Drops ... yes.
That's a registered trademark for high-quality capacitors.

Orange dips ... NO.
That's a generic name for imported garbage.

- Leigh

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 Post subject: Re: Leaky goo from Micamold capacitors
PostPosted: May Thu 30, 2019 11:59 am 
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When a paper capacitor is encased in molded Bakelite, the paper slug has to be filled with something to resist the molding pressure. This is done by injecting oil or wax into the slug right before molding. It’s slightly off topic but the first generation Black Beauties with solder eyelets were injected with water which was removed through the eyelet after the case was molded on by baking in a vacuum oven. The caps were then injected with oil for dielectric strength and leads were soldered to the eyelets.

That goo is residual oil which got out through microscopic cracks or pinholes in the cases. It is not known to be dangerous but should be handled the same as old motor or lubricating oil, i.e. after contact wash your hands before eating or smoking, etc.

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 Post subject: Re: Leaky goo from Micamold capacitors
PostPosted: May Thu 30, 2019 12:02 pm 
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Chris108 wrote:
It is not known to be dangerous but should be handled the same as old motor or lubricating oil, i.e. after contact wash your hands before eating or smoking, etc.

These were made when PCB containing oils were in widespread use. I would handle properly.


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 Post subject: Re: Leaky goo from Micamold capacitors
PostPosted: May Thu 30, 2019 2:20 pm 
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One thing to note, PCB oils were not cheap.

If it wasn't necesasary to use PCB oil, such as in high voltage capacitors, they used something else.

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 Post subject: Re: Leaky goo from Micamold capacitors
PostPosted: May Thu 30, 2019 2:37 pm 
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The only caps I can recall oozing oil is the square metal cans with the rubber seals. I have seen people try to sell them with an oily film that indicates leakage! I think I had some years ago and they got trashed or something. I am sure you can buy them on ebay in various conditions. Right next to the bumblebees and clipped out wax jobs.

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 Post subject: Re: Leaky goo from Micamold capacitors
PostPosted: May Thu 30, 2019 4:45 pm 
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Quote:
These were made when PCB containing oils were in widespread use. I would handle properly.


I've been in electronics nearly 50 years now and I have never seen anything in print or online, nor did I ever hear it from an old timer, that Micamold bakelite cased capacitors contained PCB oil. Not that that rules out the possibilty by any means, but I think the fact would be better known if it was a fact. PCB materials were expensive, so I doubt Micamold would have used them for filler.

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 Post subject: Re: Leaky goo from Micamold capacitors
PostPosted: May Thu 30, 2019 9:57 pm 
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I remember reading that mineral oil and castor oil were used back in the 1940s. Whatever it is, wash your hands!

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 Post subject: Re: Leaky goo from Micamold capacitors
PostPosted: May Fri 31, 2019 6:45 am 
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In the Cardmatic tube testers, a portion of the wiring harness goes through a section of clear tubing (early vinyl?) that has now yellowed and oozed out a oily film. I even treat that like it is hazardous waste.


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 Post subject: Re: Leaky goo from Micamold capacitors
PostPosted: May Fri 31, 2019 12:51 pm 
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That oily film is plasticizer. Nearly all forms of soft plastic require the addition of compounds to make them flexible and workable. Plasticizers break some of the molecular bonds in the plastic to soften it up. Other chemicals commonly added are UV blockers, antioxidants, and proprietary formulations to control shrinkage, elongation, or other mechanical characteristics.

Many of these additives are volatile and gradually leave the plastic. That’s why most plastics eventually shrink, yellow, become brittle, and break apart. While that oily film is not good to get on your skin and it certainly should not be ingested, you don’t need to call out the men in moon suits to carry it away in hazmat containers either. After all, that stuff was in the plastic since the day it was made and it wasn’t a problem before, so it shouldn’t be a problem now either as long as you observe the usual handling precautions which apply to most chemicals and compounds that serve no good purpose in one’s body.

Funny how people see plastics falling apart all around them every day but they think plastic film capacitors are forever!

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 Post subject: Re: Leaky goo from Micamold capacitors
PostPosted: May Fri 31, 2019 5:03 pm 
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Nothing is forever.

But plastic caps will outlive electrolytics and paper caps by a significant margin! :D

Some plastics seem to stand the test of time. How many of the 1942 black pushbutton Zeniths are deteriorating?

-Steve

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 Post subject: Re: Leaky goo from Micamold capacitors
PostPosted: May Fri 31, 2019 5:13 pm 
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azenithnut wrote:
Nothing is forever.-Steve


Cocroaches are forever.
Actually, so are diamonds. Just ask James Bond.
And furthermore, taxes are also forever ..............

that one got me depressed. signing off now ;-)

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