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Wax covered capacitors from the 1950s
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Syl
electronics forum beginner


Joined: 17 Jul 2006
Posts: 2

PostPosted: Tue Jul 18, 2006 8:20 pm    Post subject: Re: Wax covered capacitors from the 1950s Reply with quote

"John Goller, k9uwa" <k9uwaREMOVE@THISarrl.netSTUFF> wrote in message
news:aD8vg.41563$FQ1.6385@attbi_s71...
Quote:
In article <HRTug.55246$8W2.787626@wagner.videotron.net>,
personne@perdu.com
says...




Syl


Yo Syl ... what happened to your website?.. went to look at your bit about
making new old resistors.. the tech stuff won't work on the site..

John k9uwa


Hi John,

Restructuring the website. Will be done in a few dayz. You can still access
the
previous interface here: http://www.oldradioz.com/old_index.html

Syl
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Stephanie Weil
electronics forum beginner


Joined: 17 Jul 2006
Posts: 2

PostPosted: Tue Jul 18, 2006 6:33 pm    Post subject: Re: Wax covered capacitors from the 1950s Reply with quote

Quote:
n cook wrote:
I suppose there is a cottage industry of taking modern 0.5,1,2W metal oxide
resistors, molding in a fire cement wrapper and then painting with
resistance colour-code bands.


Our own Syl Vanier did that. I saw the procedure documented on his
homepage.

That right there convinced me he had totally lost his mind. ;)

--
Stephanie Weil
New York City, USA
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John Goller, k9uwa
electronics forum beginner


Joined: 18 Jul 2006
Posts: 1

PostPosted: Tue Jul 18, 2006 5:11 pm    Post subject: Re: Wax covered capacitors from the 1950s Reply with quote

In article <HRTug.55246$8W2.787626@wagner.videotron.net>, personne@perdu.com
says...
Quote:




Syl


Yo Syl ... what happened to your website?.. went to look at your bit about

making new old resistors.. the tech stuff won't work on the site..

John k9uwa
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nesesu
electronics forum beginner


Joined: 29 Jun 2005
Posts: 5

PostPosted: Tue Jul 18, 2006 4:59 pm    Post subject: Re: Wax covered capacitors from the 1950s Reply with quote

Actually, I usually paint them with the BED colour code after bending
the leads at a sharp right angle and adding some epoxy on each end to
give the 'dogbone' radial leaded shape.
[BED= Body-End-Dot coding that was common just before the colourbanding
became common.]

Neil S.

n cook wrote:
Quote:
nesesu <neil_sutcliffe@telus.net> wrote in message
news:1153194164.132231.183210@h48g2000cwc.googlegroups.com...
Fred, if you are interested, I can send a series of photos showing the
process I use in restuffing old cardboard cased paper caps and a new
process I use to make brand new cardboard cases, since I am running out
of old cap cases in some sizes, to restuff.
It is really annoying when recapping a worthwhile set to find that 3 or
4 original cardboard cased caps have been replaced with plastic or
ceramic cased replacements that are bad, but cannot easily be cleaned
out for restuffing and are, in any case, non-OEM, so I developed a
simple method of making new shells of any regular size.

Neil S.

Fred McKenzie wrote:
In article <e9fjpn$99i$1@inews.gazeta.pl>, "n cook" <diverse8@gazeta.pl
wrote:

Proudly stating "British Made"
What makes all those yellow tubular wax covered caps, Dubilier type
460, TCC
type 343, 645 etc 300V to 750V caps in range 1 to 100nF go so leaky ?
Is it
the wax is actually hygroscopic and absorbs water vapour over time. ?
On DVM resistance scale in Meg ohms but on a Megger then as low as
50Kohm.

N. Cook-

Neil pegged it. It isn't the wax that is hygroscopic as much as the
paper
used as a dielectric in such capacitors made until the late 50s.

As a teenager, I had collected boxes of components by canibalizing
equipment from a local Radio-TV repairman's trash bin. When I saved up
enough money to buy a multimeter, I found that over 90 percent of the
paper capacitors were leaky, and may have been the cause of the
equipment
failure. I learned quickly that the first step in repairing old radios,
was to replace all the paper capacitors.

Somewhere around 1957, the capacitor companys started using plastic
dielectric, sometimes in combination with paper. Names like "Mylar",
"Dipped Mylar" and "Paper-Mylar" were used to describe these newer
capacitors. From my viewpoint, that marked a turning point in the
reliability of electronic circuits.

I understand that some people who restore antique radios, will use the
case of a paper capacitor, replace the core with a mylar capacitor and
seal it again with wax.

Fred


I suppose there is a cottage industry of taking modern 0.5,1,2W metal oxide
resistors, molding in a fire cement wrapper and then painting with
resistance colour-code bands.

--
Diverse Devices, Southampton, England
electronic hints and repair briefs , schematics/manuals list on
http://home.graffiti.net/diverse:graffiti.net/
Back to top
Gary Tayman
electronics forum beginner


Joined: 20 Nov 2005
Posts: 3

PostPosted: Tue Jul 18, 2006 11:22 am    Post subject: Re: Wax covered capacitors from the 1950s Reply with quote

In regards to these "cottage industries", is there anybody out there selling
"new" OEM resistors and capacitors?

Among my many, many future projects is my Atwater Kent 60. In the process
of fixing it up, just about all the carbon resistors have been replaced.
These are white ceramic with soldered ends. I've kept the old ones, with
the high hopes that one day I'll try to make some sort of reproduction that
can go back in the radio. If somebody is selling these I may be interested.



--
Gary E. Tayman/Tayman Electrical
Sound Solutions For Classic Cars
http://www.taymanelectrical.com



"n cook" <diverse8@gazeta.pl> wrote in message
news:e9i45l$snp$1@inews.gazeta.pl...
Quote:
nesesu <neil_sutcliffe@telus.net> wrote in message
news:1153194164.132231.183210@h48g2000cwc.googlegroups.com...
Fred, if you are interested, I can send a series of photos showing the
process I use in restuffing old cardboard cased paper caps and a new
process I use to make brand new cardboard cases, since I am running out
of old cap cases in some sizes, to restuff.
It is really annoying when recapping a worthwhile set to find that 3 or
4 original cardboard cased caps have been replaced with plastic or
ceramic cased replacements that are bad, but cannot easily be cleaned
out for restuffing and are, in any case, non-OEM, so I developed a
simple method of making new shells of any regular size.

Neil S.

Fred McKenzie wrote:
In article <e9fjpn$99i$1@inews.gazeta.pl>, "n cook"
diverse8@gazeta.pl
wrote:

Proudly stating "British Made"
What makes all those yellow tubular wax covered caps, Dubilier type
460, TCC
type 343, 645 etc 300V to 750V caps in range 1 to 100nF go so leaky ?
Is it
the wax is actually hygroscopic and absorbs water vapour over time. ?
On DVM resistance scale in Meg ohms but on a Megger then as low as
50Kohm.

N. Cook-

Neil pegged it. It isn't the wax that is hygroscopic as much as the
paper
used as a dielectric in such capacitors made until the late 50s.

As a teenager, I had collected boxes of components by canibalizing
equipment from a local Radio-TV repairman's trash bin. When I saved up
enough money to buy a multimeter, I found that over 90 percent of the
paper capacitors were leaky, and may have been the cause of the
equipment
failure. I learned quickly that the first step in repairing old
radios,
was to replace all the paper capacitors.

Somewhere around 1957, the capacitor companys started using plastic
dielectric, sometimes in combination with paper. Names like "Mylar",
"Dipped Mylar" and "Paper-Mylar" were used to describe these newer
capacitors. From my viewpoint, that marked a turning point in the
reliability of electronic circuits.

I understand that some people who restore antique radios, will use the
case of a paper capacitor, replace the core with a mylar capacitor and
seal it again with wax.

Fred


I suppose there is a cottage industry of taking modern 0.5,1,2W metal
oxide
resistors, molding in a fire cement wrapper and then painting with
resistance colour-code bands.

--
Diverse Devices, Southampton, England
electronic hints and repair briefs , schematics/manuals list on
http://home.graffiti.net/diverse:graffiti.net/


Back to top
n cook
electronics forum Guru Wannabe


Joined: 11 Jan 2006
Posts: 153

PostPosted: Tue Jul 18, 2006 7:56 am    Post subject: Re: Wax covered capacitors from the 1950s Reply with quote

nesesu <neil_sutcliffe@telus.net> wrote in message
news:1153194164.132231.183210@h48g2000cwc.googlegroups.com...
Quote:
Fred, if you are interested, I can send a series of photos showing the
process I use in restuffing old cardboard cased paper caps and a new
process I use to make brand new cardboard cases, since I am running out
of old cap cases in some sizes, to restuff.
It is really annoying when recapping a worthwhile set to find that 3 or
4 original cardboard cased caps have been replaced with plastic or
ceramic cased replacements that are bad, but cannot easily be cleaned
out for restuffing and are, in any case, non-OEM, so I developed a
simple method of making new shells of any regular size.

Neil S.

Fred McKenzie wrote:
In article <e9fjpn$99i$1@inews.gazeta.pl>, "n cook" <diverse8@gazeta.pl
wrote:

Proudly stating "British Made"
What makes all those yellow tubular wax covered caps, Dubilier type
460, TCC
type 343, 645 etc 300V to 750V caps in range 1 to 100nF go so leaky ?
Is it
the wax is actually hygroscopic and absorbs water vapour over time. ?
On DVM resistance scale in Meg ohms but on a Megger then as low as
50Kohm.

N. Cook-

Neil pegged it. It isn't the wax that is hygroscopic as much as the
paper
used as a dielectric in such capacitors made until the late 50s.

As a teenager, I had collected boxes of components by canibalizing
equipment from a local Radio-TV repairman's trash bin. When I saved up
enough money to buy a multimeter, I found that over 90 percent of the
paper capacitors were leaky, and may have been the cause of the
equipment
failure. I learned quickly that the first step in repairing old radios,
was to replace all the paper capacitors.

Somewhere around 1957, the capacitor companys started using plastic
dielectric, sometimes in combination with paper. Names like "Mylar",
"Dipped Mylar" and "Paper-Mylar" were used to describe these newer
capacitors. From my viewpoint, that marked a turning point in the
reliability of electronic circuits.

I understand that some people who restore antique radios, will use the
case of a paper capacitor, replace the core with a mylar capacitor and
seal it again with wax.

Fred


I suppose there is a cottage industry of taking modern 0.5,1,2W metal oxide
resistors, molding in a fire cement wrapper and then painting with
resistance colour-code bands.

--
Diverse Devices, Southampton, England
electronic hints and repair briefs , schematics/manuals list on
http://home.graffiti.net/diverse:graffiti.net/
Back to top
nesesu
electronics forum beginner


Joined: 29 Jun 2005
Posts: 5

PostPosted: Tue Jul 18, 2006 3:42 am    Post subject: Re: Wax covered capacitors from the 1950s Reply with quote

Fred, if you are interested, I can send a series of photos showing the
process I use in restuffing old cardboard cased paper caps and a new
process I use to make brand new cardboard cases, since I am running out
of old cap cases in some sizes, to restuff.
It is really annoying when recapping a worthwhile set to find that 3 or
4 original cardboard cased caps have been replaced with plastic or
ceramic cased replacements that are bad, but cannot easily be cleaned
out for restuffing and are, in any case, non-OEM, so I developed a
simple method of making new shells of any regular size.

Neil S.

Fred McKenzie wrote:
Quote:
In article <e9fjpn$99i$1@inews.gazeta.pl>, "n cook" <diverse8@gazeta.pl> wrote:

Proudly stating "British Made"
What makes all those yellow tubular wax covered caps, Dubilier type 460, TCC
type 343, 645 etc 300V to 750V caps in range 1 to 100nF go so leaky ? Is it
the wax is actually hygroscopic and absorbs water vapour over time. ?
On DVM resistance scale in Meg ohms but on a Megger then as low as 50Kohm.

N. Cook-

Neil pegged it. It isn't the wax that is hygroscopic as much as the paper
used as a dielectric in such capacitors made until the late 50s.

As a teenager, I had collected boxes of components by canibalizing
equipment from a local Radio-TV repairman's trash bin. When I saved up
enough money to buy a multimeter, I found that over 90 percent of the
paper capacitors were leaky, and may have been the cause of the equipment
failure. I learned quickly that the first step in repairing old radios,
was to replace all the paper capacitors.

Somewhere around 1957, the capacitor companys started using plastic
dielectric, sometimes in combination with paper. Names like "Mylar",
"Dipped Mylar" and "Paper-Mylar" were used to describe these newer
capacitors. From my viewpoint, that marked a turning point in the
reliability of electronic circuits.

I understand that some people who restore antique radios, will use the
case of a paper capacitor, replace the core with a mylar capacitor and
seal it again with wax.

Fred
Back to top
Phil Nelson
electronics forum beginner


Joined: 15 Jul 2006
Posts: 2

PostPosted: Tue Jul 18, 2006 2:42 am    Post subject: Re: Wax covered capacitors from the 1950s Reply with quote

Quote:
I understand that some people who restore antique radios, will use the
case of a paper capacitor, replace the core with a mylar capacitor and
seal it again with wax.

For more details on capacitor replacement (including restuffing), you can
read:

http://antiqueradio.org/recap.htm

Regards,

Phil Nelson
Phil's Old Radios
http://antiqueradio.org/index.html
Back to top
Stephanie Weil
electronics forum beginner


Joined: 17 Jul 2006
Posts: 2

PostPosted: Mon Jul 17, 2006 8:15 pm    Post subject: Re: Wax covered capacitors from the 1950s Reply with quote

nesesu wrote:
Quote:
The leakage is not an issue of moisture migrating into the capacitor
'jellyroll' slug directly, but once there is some moisture in the slug
in combination with the sulphites in the kraft paper,

I wonder if this is part of what kills a supposedly better-sealed
"Black Beauty" (paper cap sealed in a molded plastic capsule)?

--
Stephanie Weil
New York, USA
Back to top
Fred McKenzie
electronics forum addict


Joined: 12 May 2005
Posts: 80

PostPosted: Mon Jul 17, 2006 5:52 pm    Post subject: Re: Wax covered capacitors from the 1950s Reply with quote

In article <e9fjpn$99i$1@inews.gazeta.pl>, "n cook" <diverse8@gazeta.pl> wrote:

Quote:
Proudly stating "British Made"
What makes all those yellow tubular wax covered caps, Dubilier type 460, TCC
type 343, 645 etc 300V to 750V caps in range 1 to 100nF go so leaky ? Is it
the wax is actually hygroscopic and absorbs water vapour over time. ?
On DVM resistance scale in Meg ohms but on a Megger then as low as 50Kohm.

N. Cook-

Neil pegged it. It isn't the wax that is hygroscopic as much as the paper
used as a dielectric in such capacitors made until the late 50s.

As a teenager, I had collected boxes of components by canibalizing
equipment from a local Radio-TV repairman's trash bin. When I saved up
enough money to buy a multimeter, I found that over 90 percent of the
paper capacitors were leaky, and may have been the cause of the equipment
failure. I learned quickly that the first step in repairing old radios,
was to replace all the paper capacitors.

Somewhere around 1957, the capacitor companys started using plastic
dielectric, sometimes in combination with paper. Names like "Mylar",
"Dipped Mylar" and "Paper-Mylar" were used to describe these newer
capacitors. From my viewpoint, that marked a turning point in the
reliability of electronic circuits.

I understand that some people who restore antique radios, will use the
case of a paper capacitor, replace the core with a mylar capacitor and
seal it again with wax.

Fred
Back to top
n cook
electronics forum Guru Wannabe


Joined: 11 Jan 2006
Posts: 153

PostPosted: Mon Jul 17, 2006 4:37 pm    Post subject: Re: Wax covered capacitors from the 1950s Reply with quote

nesesu <neil_sutcliffe@telus.net> wrote in message
news:1153148416.223932.174400@75g2000cwc.googlegroups.com...
Quote:
The leakage is not an issue of moisture migrating into the capacitor
'jellyroll' slug directly, but once there is some moisture in the slug
in combination with the sulphites in the kraft paper, they promote
aluminum ions of the foil in the slug to begin to migrate into the
paper dielectric. These ions eventually cause leakage paths to form
through the paper, or worse, cause a moderately high conductive path
that, with a high bias voltage, will cause it to carbonize and cause a
high leakage path or full short. If the cap moves to a dry location the
moisture theoretically will migrate out again, but the ionic migration
does not reverse--just slows down.
The "tropical" wax that I use in paper cap rebuilding may be somewhat
better than the 'filled' potting and slug waxes of consumer grade paper
caps, but it's main difference is the anti-fungicides it contains to
delay the formation of molds and mill-dew on the organic components.

Neil S.

n cook wrote:
Proudly stating "British Made"
What makes all those yellow tubular wax covered caps, Dubilier type 460,
TCC
type 343, 645 etc 300V to 750V caps in range 1 to 100nF go so leaky ? Is
it
the wax is actually hygroscopic and absorbs water vapour over time. ?
On DVM resistance scale in Meg ohms but on a Megger then as low as
50Kohm.

--
Diverse Devices, Southampton, England
electronic hints and repair briefs , schematics/manuals list on
http://home.graffiti.net/diverse:graffiti.net/


Strange thing this mold/midew stuff, this is one of the strangest fault
causes I've ever had

Scopex 14D10 scope
Nasty noise from the ps and nothing else.
Using an isolation transformer and observing on a scope
there was low level oscillation of the smps and one burst of
oscillator per cycle of the mains.This smps is the type with
the oscillator on the mains side of the pulse transformer.
All active components seemed ok and no leaky caps.
Putting a dc supply across the oscillator and varying
the voltage the drive to the main trannie changed state
at about 20V.Disconnecting the pulse transformer and
testing with a megger (high v insulayion tester) there
was no interwinding breakdown and the inductance of
the coils looked right (no shorted turns).Eventually found
the O/P was being loaded by a faulty opto-isolator that
gates the beam current.It was ohmic between I/P
and O/P so removed and cracked open with mole grips
(vice grip locking pliers).Looking at the transparent
bridge under a 30x microscope there were tiny circles of
mold or fungus that had grown and coalesced forming
a resistive bridge between I/P and O/P.

--
Diverse Devices, Southampton, England
electronic hints and repair briefs , schematics/manuals list on
http://home.graffiti.net/diverse:graffiti.net/
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nesesu
electronics forum beginner


Joined: 29 Jun 2005
Posts: 5

PostPosted: Mon Jul 17, 2006 3:00 pm    Post subject: Re: Wax covered capacitors from the 1950s Reply with quote

The leakage is not an issue of moisture migrating into the capacitor
'jellyroll' slug directly, but once there is some moisture in the slug
in combination with the sulphites in the kraft paper, they promote
aluminum ions of the foil in the slug to begin to migrate into the
paper dielectric. These ions eventually cause leakage paths to form
through the paper, or worse, cause a moderately high conductive path
that, with a high bias voltage, will cause it to carbonize and cause a
high leakage path or full short. If the cap moves to a dry location the
moisture theoretically will migrate out again, but the ionic migration
does not reverse--just slows down.
The "tropical" wax that I use in paper cap rebuilding may be somewhat
better than the 'filled' potting and slug waxes of consumer grade paper
caps, but it's main difference is the anti-fungicides it contains to
delay the formation of molds and mill-dew on the organic components.

Neil S.

n cook wrote:
Quote:
Proudly stating "British Made"
What makes all those yellow tubular wax covered caps, Dubilier type 460, TCC
type 343, 645 etc 300V to 750V caps in range 1 to 100nF go so leaky ? Is it
the wax is actually hygroscopic and absorbs water vapour over time. ?
On DVM resistance scale in Meg ohms but on a Megger then as low as 50Kohm.

--
Diverse Devices, Southampton, England
electronic hints and repair briefs , schematics/manuals list on
http://home.graffiti.net/diverse:graffiti.net/
Back to top
Michael A. Terrell
electronics forum Guru


Joined: 24 Mar 2005
Posts: 2291

PostPosted: Mon Jul 17, 2006 1:47 pm    Post subject: Re: Wax covered capacitors from the 1950s Reply with quote

n cook wrote:
Quote:

If they were not wax covered would they still have been be problematic ?
Understandable in a damp environment but indoors would dampness get in the
paper and not evaporate again if not waxed, the use of wax sealing the
dampness/vapour/condensate insde each cap?


Some of the wax boils away over time, and they made the capacitors
out of what was available at the time. Thermal cycling will let
moisture into the capacitor as the coating starts to break down.


--
Service to my country? Been there, Done that, and I've got my DD214 to
prove it.
Member of DAV #85.

Michael A. Terrell
Central Florida
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Syl
electronics forum beginner


Joined: 17 Jul 2006
Posts: 2

PostPosted: Mon Jul 17, 2006 1:05 pm    Post subject: Re: Wax covered capacitors from the 1950s Reply with quote

"Paul Sherwin" <root@localhost.localdomain> wrote in message
news:e9fpoh$88t$1$8302bc10@news.demon.co.uk...
Quote:
On Mon, 17 Jul 2006 10:04:34 +0100, n cook wrote:

Proudly stating "British Made"
What makes all those yellow tubular wax covered caps, Dubilier type 460,
TCC
type 343, 645 etc 300V to 750V caps in range 1 to 100nF go so leaky ? Is
it
the wax is actually hygroscopic and absorbs water vapour over time. ?
On DVM resistance scale in Meg ohms but on a Megger then as low as
50Kohm.

Yes, the wax is hygroscopic. The problem isn't restricted to British caps,
most non-tropicalised consumer grade paper caps from the 40s and 50s will
be leaky now.

Paul


ALL paper caps go bad with time, whether they are "tropicalized" or sealed
like the infamous Black Beauty.

Oil caps on the other hand have a pretty good lifetime. I have a Russian
made radio and the sealed oil caps are still good.
There are no paper/wax caps in that radio. Parts are military grade, and I
mean military grade.

Syl
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n cook
electronics forum Guru Wannabe


Joined: 11 Jan 2006
Posts: 153

PostPosted: Mon Jul 17, 2006 11:02 am    Post subject: Re: Wax covered capacitors from the 1950s Reply with quote

Paul Sherwin <root@localhost.localdomain> wrote in message
news:e9fpoh$88t$1$8302bc10@news.demon.co.uk...
Quote:
On Mon, 17 Jul 2006 10:04:34 +0100, n cook wrote:

Proudly stating "British Made"
What makes all those yellow tubular wax covered caps, Dubilier type 460,
TCC
type 343, 645 etc 300V to 750V caps in range 1 to 100nF go so leaky ? Is
it
the wax is actually hygroscopic and absorbs water vapour over time. ?
On DVM resistance scale in Meg ohms but on a Megger then as low as
50Kohm.

Yes, the wax is hygroscopic. The problem isn't restricted to British caps,
most non-tropicalised consumer grade paper caps from the 40s and 50s will
be leaky now.

Paul

If they were not wax covered would they still have been be problematic ?
Understandable in a damp environment but indoors would dampness get in the
paper and not evaporate again if not waxed, the use of wax sealing the
dampness/vapour/condensate insde each cap?

--
Diverse Devices, Southampton, England
electronic hints and repair briefs , schematics/manuals list on
http://home.graffiti.net/diverse:graffiti.net/
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