Growing conductive fuzz

Growing conductive fuzz

Post by Ken » Tue, 07 Mar 2006 11:23:10



In tuning capacitors . I have run into this to many times and have found
no way to cure it .The last one i cleaned till it worked then spray can
lacquered down into the plates now the radio preforms poor . No static
just half sensitivity now
 
 
 

Growing conductive fuzz

Post by Terry » Tue, 07 Mar 2006 11:42:12


I have had good results cleaning out metal whiskers by applying 120V through
a 60 watt lamp between the rotor and stator. Your lacquer increased the
dielectric between the plates which causes the capacitance to increase and
also losses to go up. Air is next to a vacuum  in lowest dielectric losses.

Quote:
> In tuning capacitors . I have run into this to many times and have found
> no way to cure it .The last one i cleaned till it worked then spray can
> lacquered down into the plates now the radio preforms poor . No static
> just half sensitivity now


 
 
 

Growing conductive fuzz

Post by Peter Wiec » Wed, 08 Mar 2006 05:49:27


Ken:

I have found rinsing the cap thoroughly with WD-40 then drying it out
with canned air gets all the fuzzies out of the system pretty well. But
with some strong caveats:

a) Do this outside, over a trash-can with about an inch of kitty-litter
in the bottom.
b) Allow the whole shebang to dry thoroughly in a warm spot for at
least a full day before applying power. And if there is any residual
liquid, let it dry some more until it is gone.
c) re-lubricate the bearings and any other parts that the WD-40 touched
and require lubrication. WD-40 itself is 100% volatile over time.

Brake cleaner works well also, but will remove any *** parts and/or
insulation in its path and craze some plastics. That *MUST* be used
outside and where the overspray/residual cannot get into the ground or
ground water. Same caveats for relubrication.

NOTE: Try dry compressed air first. Mostly that works fine if you can
get enough pressure, and the air dry enough. Canned air is a second
choice. Only after these expedients fail should one go on to a more
intensive process.

Try cleaning the little brass wipers with a bit of fine sand-paper
between them and the frame. Then retension them with a dental-pick They
are what conducts from the rotor, so if you have lacquered them, they
may be conduction poorly either at the rotor or where they bear on the
frame.

Peter Wieck
Wyncote, PA

 
 
 

Growing conductive fuzz

Post by Terry » Wed, 08 Mar 2006 09:47:04


I use auto tire sidewall cleaner followed by a thorough rinse. Dry for a
couple of days on the shop heater then relube. Looks and works like new.
Gets nicotine and kitchen grease off without scrubbing.

Quote:
> Ken:

> I have found rinsing the cap thoroughly with WD-40 then drying it out
> with canned air gets all the fuzzies out of the system pretty well. But
> with some strong caveats:

> a) Do this outside, over a trash-can with about an inch of kitty-litter
> in the bottom.
> b) Allow the whole shebang to dry thoroughly in a warm spot for at
> least a full day before applying power. And if there is any residual
> liquid, let it dry some more until it is gone.
> c) re-lubricate the bearings and any other parts that the WD-40 touched
> and require lubrication. WD-40 itself is 100% volatile over time.

> Brake cleaner works well also, but will remove any *** parts and/or
> insulation in its path and craze some plastics. That *MUST* be used
> outside and where the overspray/residual cannot get into the ground or
> ground water. Same caveats for relubrication.

> NOTE: Try dry compressed air first. Mostly that works fine if you can
> get enough pressure, and the air dry enough. Canned air is a second
> choice. Only after these expedients fail should one go on to a more
> intensive process.

> Try cleaning the little brass wipers with a bit of fine sand-paper
> between them and the frame. Then retension them with a dental-pick They
> are what conducts from the rotor, so if you have lacquered them, they
> may be conduction poorly either at the rotor or where they bear on the
> frame.

> Peter Wieck
> Wyncote, PA

 
 
 

Growing conductive fuzz

Post by Ken » Wed, 08 Mar 2006 10:01:10


Thanks guys . I have not tried the 120 volts & bulb yet . Here is what i
have tried
.
1 Clean cap with forced air and long stiff brush in all sets of plates .
I could see the dust & stuff poof out of the cap . Re-install in radio
and it works great for a month then it comes back .

2 Remove cap and put in ultrasonic cleaner , blow dry and lube .. same
results .. it comes back .

3 fix up a piece of thin plastic with cloth to buff between all plates
with WD-40 , blow dry .. same results . it comes back .

I look in the cap plates with a light each time and see thousands of
fine peach fuzz all over every plate .

One radio this has deen a problem in is a Crosley O2CA that i have had
for 15? years or so . I bought another O2CA to restore and it has the
same fuzz in the tuner which i killed with lacquer . I will lacquer
thiner the tuner next summer .
One other radio with this problem is a small AA5  Olympic

 
 
 

Growing conductive fuzz

Post by Ken » Wed, 08 Mar 2006 11:20:38


Yes i have used the tire cleaner too . The fuzz comes back in time .
 
 
 

Growing conductive fuzz

Post by Gordon Richmon » Wed, 08 Mar 2006 13:01:24


Quote:
>Thanks guys . I have not tried the 120 volts & bulb yet . Here is what i
>have tried
>.
>1 Clean cap with forced air and long stiff brush in all sets of plates .
>I could see the dust & stuff poof out of the cap . Re-install in radio
>and it works great for a month then it comes back .

>2 Remove cap and put in ultrasonic cleaner , blow dry and lube .. same
>results .. it comes back .

>3 fix up a piece of thin plastic with cloth to buff between all plates
>with WD-40 , blow dry .. same results . it comes back .

>I look in the cap plates with a light each time and see thousands of
>fine peach fuzz all over every plate .

>One radio this has deen a problem in is a Crosley O2CA that i have had
>for 15? years or so . I bought another O2CA to restore and it has the
>same fuzz in the tuner which i killed with lacquer . I will lacquer
>thiner the tuner next summer .
>One other radio with this problem is a small AA5  Olympic

Sounds like perhaps the capacitor plates were made from a bad batch of metal, or got
exposed to some contaminant that has compromised the thin coating of aluminum oxide that
normally protects the metal from further oxidation. Perhaps there is some kind of chemical
treatment that could restore the surface?

If you want to see a graphic illustration of this kind of corrosion in action, get a piece
of s***aluminum, and rub a drop of mercury into it with a wad of steel wool. This
creates a domain of aluminum amalgam on the surface of the metal, which effectively breaks
that oxide barrier. That amalgamated patch will continuously grow long white whiskers of
aluminum oxide unitl it eats right through the piece of scrap.

I learned this the hard way back in high school, when I found bunch of spilled mercury in
the dirt at school. I scooped up the dirt, and panned out the mercury using an old
aluminum baking dish. The white whiskers grew, and grew, and grew. Eventually the pan was
riddled with tiny holes. That's why airlines have fits if you bring mercury on board.

It may well be the only permanent cure is to replace the problem tuning cap.

Gordon Richmond

 
 
 

Growing conductive fuzz

Post by philsvintageradio » Wed, 08 Mar 2006 13:01:53


Quote:

> Yes i have used the tire cleaner too . The fuzz comes back in time .

ok here's my two bits worth, about cleaning in general.

the fuzz will stick to anything oily. my preferred method is:

blow/ light brush it off with dry air
wash with water and soap. let dry,
solvant, blow off
water again blow off
solvent again blow off
***. blow dry.
grease the bearings

* don't forget all the safety issues this involves. especially
atomizing *** !
and whatever you do , don't bend the fins !

- my reasoning:
the dry brush off avoids dissolving the dust.

Water and solvent based washing, because some things dissolve in water,
and some things dissolve in solvent,  I think of them like opposite
species.

The solvant might be WD, solvant, kerosene, paint thinner, engine
cleaner, control cleaner etc.
Layers of either may prevent the dissolving of the other, that's why I
alternate.

The ***, or whichever dangerous high flash solvent you choose like
acetone, xylene tolene,carb spray etc, will get rid of the greasiness,
whch attracts more dust. one dousing at the end of the previous things
is enough.

If we bend the fins it will probably not just  mess up the allignment
but also tracking between bands, so I don't want to take the chance of
going down that road. For this reason I hold the air at a distance
where necessary. and use a soft brush lightly.  and I try not to get
the cleaning stuff down into the chassis because it turns the wires to
gush. the mica insulators in the tining cap trimmers can't stand up to
a strong air blast.

Phil

 
 
 

Growing conductive fuzz

Post by Ken » Wed, 08 Mar 2006 13:44:25


Hi Phil .. the tuning cap has been out of the Crosley chassis several
times and cleaned several ways . It always works great after the
cleaning with just the air & long brush and left dry as a bone . looking
at it with a light shows no fuzz and It works fine till a month or 3
goes by then the flashlight & fuzz again .

I do believe the metal is defective . I have been looking for
replacements from junk chassis . You cant emagine all the thousands of
designs on these tuners that stop me from trying to sub one in . Its
amazing . one day maybe !

 
 
 

Growing conductive fuzz

Post by philsvintageradio » Wed, 08 Mar 2006 14:25:01


sounds frustrating, maybe some of the fins are just about touching?
maybe wear in the bearings has caused the shaft to shift over a little?

I haven't tried the method of electrifying the plates to look for a
spark but it sounds like a good one.
maybe put a meter across the plates and see if light pressure ( like
pushing it with a piece of paper) causes it to short somehow?
Phil

 
 
 

Growing conductive fuzz

Post by Ken » Wed, 08 Mar 2006 15:34:14


Good point & forgot to mention i have used a meter across the thing and
it shows no reading . Also played around with the spacing , bending of
plates with a light from the other side & all the tricks . I do know for
sure that fuzz grows & comes back , i can see it .
Also did about everything with the copper or brass ground clips as Peter
W mentioned .
No big deal just thought someone else may have found a cure .
I need to add a ``clean ``button to the chassis running hi voltage
through the cap
Band switch .. AM , SW , Police , clean .