Soaking NOS caps in IPAlcohol

[sarakisof]

Found some yummy NOS caps from an old shop's retirement clearance stock the other day.
Many dirt and dust on there, so i was thinking of soaking them in 99.9 IPA for a minute or so, then sort in shelves.
(Already done for the mullard's).
Mostly wonder about some polystyrene and paper ones(and electros maybe?). Is there any danger of doing so?

 

[JohnRoberts]

Back in the 80s my business partner trashed an entire production run of PCBs by trying to clean off the PCBs with water(?) and a high pressure air hose. He ended up blowing water inside some of the polystyrene caps that I used lots of back then in audio filters. It took me a little bit to figure out why I had so many bad polystyrene caps all of a sudden.

JR

 

[k brown]

I'll have to get out all my old caps and soak them in India Pale Ale.

 

[JohnRoberts]

I'll have to get out all my old caps and soak them in India Pale Ale.

the excessive hops may make your sound bitter...

JR

PS: Just kidding

 

[k brown]

D*amn - I was hoping for the latest Golden Ear tweak . . .

 

[sarakisof]

I'll have to get out all my old caps and soak them in India Pale Ale.

No water here. Just pure 99.9 Isopropyl Alcohol. I'm ready to go, pull out the styrene/papers or soak all of them?

 

[dmp]

I would definitely not soak them. If a little dust bothers you, wipe them off
Electrolytics are probably not worth installing in anything

You could test them all for leakage

 

[abbey road d enfer]

When I read the title, I asked myself, why soak capacitors in beer,...?

 

[dr.minutia]

Do NOT soak them. That's an absurd "resurrection" method that never should have seen daylight.

Test the polys and paper in oils on an LCR - if paper in oils are off-spec I'd toss them or use them as guitar tone caps if they are in the right range - I used to collect "brown turds" from 70's Fenders and use them as tone caps - smooth, linear rolloff. But in a circuit under load they're not really dangerous yet unstable and whatever you read today may change the minute they are under load.

NOS and "pull" electrolytics are time bombs. Nice to put on display if you have a shop, with a sign reading "Do not EVER use these, and replace any you find in your gear or gear you service." Even if they "look" OK they can blow in a second without warning - I've replaced a lot of power transformers in guitar amps over the years for that reason. They are only good in museum-display, never powered up gear.

 

[k brown]

Not to mention the fact that really old, large can caps can have PCB inside them!

From your photo, it doesn't look like you have any of those.

 

[Whoops]

Electrolytics are probably not worth installing in anything

I was going to say exactly the same thing.
I would toss all the electrolytics and all the PIO caps.

It's very well know that PIO caps are not trustworthy the same for old and never used electrolytic capacitors

 

[C12VR]

Don't certain caps dissolve in alcohol?

 

[Whoops]

Don't certain caps dissolve in alcohol?

I never seen that happening.
I wouldn't have any problem myself in soaking capacitors in 99.9% Iso Alcohol,
as it evaporates quite fast and doesn't leave any residue

 

[sarakisof]

I know i know all mentioned above .
Didn't soak any styrene & PIOs though.
About Isopropyl, if your main job is pharmacist like me, it's quite obvious what do you mean when u say IPA .
No any IPA named beer where I live, only Mythos,Amstel, greek tsipouro & ouzo lol.

Well I'll only probably use some of the ecaps, if any, wisely & carefully.
Leakage: no fancy, experience test gear here, tested some using this method

Sum up, after 5mins., bigger ones (470/100, 1000/50, 2200/40 etc) measured in the ballpark of 5-30μA and smaller ones at 0.01-2μA.
Capacitance: only few were higher enough.
ESR: I don't trust enough my cheapo LCR T4 chinese tester, but as far as i can tell they measured good enough, compared to fresh Nippon's, FR Panasonics (nos Matsushitas measured better actually) n Nichi's.

How demanding would be anyway to replace those common culprit cracked red/brown polarized ROE EK's (C27/28, C37/38 scheme) in my Hohner Pianet M's output stage?
https://www.clavinet.com/shema_PIANET_M.pdfI guess 4xNOS 100μ/63V Siemens or Philips would be perfect there.

In some cases (Im not talking about HVolts, filtering valve equipment and critical circuits), got tired of paying so much money on "fresh" (realising they're over decade when go home after having locally purchased them - mouser and other big ones are 1,2 times per year for me) Nichicons, Panasonics etc. and having A/B tested with many engineers here on plenty of pedals , realising again they are also more stiff & aggressive compared to the original ones used in the units.
Those are personal preferences anyway.

 

[dr.minutia]

Don't certain caps dissolve in alcohol?

Paper-covered types will usually lose the covering, as the adhesives are normally dissolved in alcohol.

But you'd be setting up an assembly line of soaking, testing and writing values on just about any type - the ink will almost always be gone or blurred.