[Boatanchors] Electrolytic Reforming Time

Bob Jackson bob at nofrowns.net
Sat Dec 31 20:35:46 EST 2011 

Lee -

I'm somewhat puzzled and even a bit amused that this particular thread has 
gone on for so long. At the risk of protracting it even further ...

I, too, agree with you and Carl. I've even seen "partial" replacements where 
one or two sections of an old multi-section cap have been reformed and left 
in circuit, and the only one(s) that "can't-get-it-to-reform" replaced. 
Nonsense in the highest degree. I suppose putting new caps inside the old 
can (or tube - melt out the wax, put in the new caps and refill with wax) to 
preserve the "look and feel" of the original perhaps may have some 
anal-retentive cosmetic merit. However, considering the time and bother to 
achieve such correctly, it's not something I'd ever do. (I do routinely 
leave the vertical can cap on the top of the chassis in place (but wholly 
disconnected) for cosmetic purposes while the modern replacements remain 
hidden underneath.)

Moreover, reforming/reusing old caps, in my mind, doesn't show respect for 
the equipment. If the thing is worth restoring in the first place, then it's 
worth bringing it back to life not only to its original performance but also 
its reliability and design longevity. Recall - most if not all of these 
"boats" weren't made under the marketing philosophy of "designed obsolesce" 
that's prevalent today. (How many iPhones does it take to change a P/L 
report?) It seems to me that "reforming", etc. is more in the  realm of 
"gee whiz, look what I can do" much like the gratuitous, over use of 
computer-generated graphics in many of today's movies, i.e. a bit of a "show 
off", ego trip for the person at the controls.

Still, at the end of the day, we each have our own, particular (perhaps even 
peculiar) "operating parameters" that govern our behavior as we pursue this 
hobby. Clearly, our time and other resources, along with our goals and 
values, are our own personal concern, and no one else's.

73 to all,

Bob  AG5X

----- Original Message ----- 
From: "lee" <pulsarxp at embarqmail.com>
To: <boatanchors at mailman.qth.net>
Sent: Saturday, December 31, 2011 6:48 PM
Subject: Re: [Boatanchors] Electrolytic Reforming Time


> Carl and others,
>
> I agree, using old electrolytics even when reformed is foolishness.   My
> suggestion to those doing so is, right after installation of a 50 year old
> cap which was designed to last around 6 years is to immediately buy an
> insurance policy on your apparatus and then make a copy of this e-mail.
> When the thing blows up in your face, read the warning e-mail, and please
> don't wine on the list when it fails, and it will fail.
>
> To be honest I am beginning to wonder why I belong to any list knowingly
> suggesting this type of foolishness.  As a learning experience, reforming 
> is
> just fine or used in an emergency which I cannot see happening with anyone
> on this list.  Doing so for some old piece of junk and not caring if the
> thing blows up may be one other exception.  For the life of me,  I cannot
> understand why someone would want to install a time bomb in his pet
> historical project, take the time to do it, and at the same time avoid 
> using
> a modern, fresh, and better made capacitor which today costs very little.
> You can rebuild an old three section can electrolytic for $5-$10 or buy 
> 450
> volt axials for less then $5 each.
>
> You won't find me playing Russian Rue let with my old equipment using this
> bad practice.
>
> Lee, w0vt
>
>
> -----Original Message----- 
> From: Geoff
> Sent: Saturday, December 31, 2011 4:20 PM
> To: W9RAN at oneradio.net ; boatanchors at mailman.qth.net
> Subject: Re: [Boatanchors] Electrolytic Reforming Time
>
> Id tend to flip those percentages to maybe 10-20% and thats with very high
> quality caps and some fairly late ones.
>
> It seems to me that we only hear from the same "reformers" over and over 
> and
> the failed ones are very silent while licking their wounds and searching 
> for
> new transformers or a rewinder.
>
> Just my $.02
>
> Carl
> KM1H
>
>
>
> ----- Original Message ----- 
> From: "Robert Nickels" <ranickel at comcast.net>
> To: <boatanchors at mailman.qth.net>
> Sent: Saturday, December 31, 2011 4:32 PM
> Subject: Re: [Boatanchors] Electrolytic Reforming Time
>
>
>> On 12/30/2011 11:50 PM, Phil wrote:
>>> So, it doesn't pay to take any chances with those 'lytics.
>> I agree with all that's been said but would just add that this business
>> of "bringing it up slowly on a variac" should be relegated to the urban
>> legends file.  It's better than just applying full AC power, but is
>> still guesswork.   The only way to properly reform an electrolytic -
>> regardless of age - is to limit (and measure) the amount of current
>> being applied to attempt to "reform" the anode oxide layer that was
>> "formed" at the factory when the cap was manufactured.
>>
>> A good description of how the aluminum electrolytic capacitor works can
>> be found here:
>> http://www.elna-america.com/tech_al_principles.php
>>
>> And here's a good reference for how to reform capacitors properly as
>> well as some alternatives:
>> http://www.nmr.mgh.harvard.edu/~reese/electrolytics/
>>
>> I prefer to measure and limit the current to about 5 ma while the oxide
>> layer is reforming; trying to do the job by simply cranking up a variac
>> every so often might work some of the time, but is like tuning your rig
>> while blindfolded.
>>
>> I generally just replace electroyltics that are  cheap and readily
>> available and attempt to reform those that aren't.  I think most
>> "reformers" find the process can restore 80-90% of old caps when done
>> right, without fear of explosions or failure.
>>
>> 73, Bob W9RAN
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>
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