I've always wondered how they paint on the colored stripes. I put "how
do they paint the stripes on resistors" on google, but all I got was
links explaining how to READ color codes.

Has anyone ever heard anything about this process?

On 9/09/2017 10:11 AM, wrote:
I've always wondered how they paint on the colored stripes. I put "how
do they paint the stripes on resistors" on google, but all I got was
links explaining how to READ color codes.

Has anyone ever heard anything about this process?


They get the christmas elves in the off season to paint them on with
their toy decorating brushes.

In article ,
says...

I've always wondered how they paint on the colored stripes. I put "how
do they paint the stripes on resistors" on google, but all I got was
links explaining how to READ color codes.

Has anyone ever heard anything about this process?

No, but after an hour or so hunting through my father's random box of
hundreds of resistors looking for the value I wanted, I got a powerful
urge to take any old one and paint on the right colours... (Never did,
though!)

Mike.

On Friday, September 8, 2017 at 11:12:02 PM UTC-4, wrote:
I've always wondered how they paint on the colored stripes. I put "how
do they paint the stripes on resistors" on google, but all I got was
links explaining how to READ color codes.

Has anyone ever heard anything about this process?



We could tell you, but then we'd have to kill you. Legal mumbo jumbo out of the way, would you like me to explain it to you?

wrote:
I've always wondered how they paint on the colored stripes. I put "how
do they paint the stripes on resistors" on google, but all I got was
links explaining how to READ color codes.

Has anyone ever heard anything about this process?

Isn't it obvious? Early resistors were hand painted, then they
developed machines for the job.



--
Never **** off an Engineer!

They don't get mad.

They don't get even.

They go for over unity! ;-)

On 9/9/2017 5:21 AM, Michael A. Terrell wrote:
wrote:
I've always wondered how they paint on the colored stripes. I put "how
do they paint the stripes on resistors" on google, but all I got was
links explaining how to READ color codes.

Has anyone ever heard anything about this process?

Isn't it obvious? Early resistors were hand painted, then they
developed machines for the job.





how did they paint the machines?

On Fri, 08 Sep 2017 22:11:09 -0400, wrote:

I've always wondered how they paint on the colored stripes. I put "how
do they paint the stripes on resistors" on google, but all I got was
links explaining how to READ color codes.

I suspect you could guess how it's done without any assistance.

My guess(tm) is that the resistors are hand painted in Japan as a
spare time project for highly skilled porcelain painters. Whey they
get bored, we get resistors like this:
https://img0.etsystatic.com/174/0/8168616/il_340x270.1181159266_6pfz.jpg
https://www.etsy.com/market/resistor_jewelry
https://www.pinterest.com/search/pins/?q=resistor jewelry

Has anyone ever heard anything about this process?

Nope. I couldn't find anything under "axial resistor marking
machine", "axial resistor color code marking device", or something
similar. Nothing under patents. Oddly, the color code itself doesn't
seem to be patented. The marking method is probably part of a highly
automated manufacturing process and either a well protected trade
circuit, or so trivial that nobody has bothered to make a dedicated
resistor marking machine. I'll add it to my list of unexplained
electronic phenomenon.

--
Jeff Liebermann
150 Felker St #D http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann AE6KS 831-336-2558

On 09/09/2017 08:21 AM, Michael A. Terrell wrote:
wrote:
I've always wondered how they paint on the colored stripes. I put "how
do they paint the stripes on resistors" on google, but all I got was
links explaining how to READ color codes.

Has anyone ever heard anything about this process?

Â*Â* Isn't it obvious? Early resistors were hand painted, then they
developed machines for the job.



Angelfish caps (Mullard) were dipped in paint to different depths to
form the stripes.

Cheers

Phil Hobbs

--
Dr Philip C D Hobbs
Principal Consultant
ElectroOptical Innovations LLC
Optics, Electro-optics, Photonics, Analog Electronics

160 North State Road #203
Briarcliff Manor NY 10510

hobbs at electrooptical dot net
http://electrooptical.net

On 9-9-2017 14:35, Taxed and Spent wrote:
On 9/9/2017 5:21 AM, Michael A. Terrell wrote:
wrote:
I've always wondered how they paint on the colored stripes. I put "how
do they paint the stripes on resistors" on google, but all I got was
links explaining how to READ color codes.

Has anyone ever heard anything about this process?

Isn't it obvious? Early resistors were hand painted, then they
developed machines for the job.





how did they paint the machines?

Carefully.

On Sat, 9 Sep 2017 08:21:13 -0400, "Michael A. Terrell"
wrote:

wrote:
I've always wondered how they paint on the colored stripes. I put "how
do they paint the stripes on resistors" on google, but all I got was
links explaining how to READ color codes.

Has anyone ever heard anything about this process?

Isn't it obvious? Early resistors were hand painted, then they
developed machines for the job.

It's a no brainer they use a machine. My question goes much deeper. How
does the machine do it? Are the paints applied by a paint brush, or
something like a felt tip marker, or maybe some sort of spray method?
Once the correct colors are chosen for that batch of (whatever value),
how do they rotate them so the paint is not smeared. I can only assume
they are picked up by their leads, not the body, and somehow rotated by
their leads too.

I do believe the early resistors, especially those ceramic types that
had colored dots on them, were probably hand painted. I have also noted
that the old bumble bee caps often had irregular stripes, where the
paint was thicker in spots, thinner in others, and the edges were not
always precise.

There is a series on tv, which is usually only shown on Saturday
mornings, during the kids shows, that show how an item is made. The ones
I remember are making candy, and making lightbulbs (incandescent). They
show the entire process, start to finish, and show each step both in the
machines and how workers are involved. I cant recall the name of them
programs, and have not seen any in a long time, but they are quite
interesting. That lightbulb one was extremely interesting. Each bulb is
tested in a machine and workers watch ot make sure they light up. Seeing
this, (on tv or youtube), for resistors would be interesting. Too bad
they dont have more stuff like that on tv, rather than the usual garbage
that is mostly on the channels these days.

One thing I do know, is that most small electronic parts with wire
leads, leave the factory in the form of ladders. Meaning that 100 or
1000, or any other number of them are one long strip being held together
by 2 strips of paper around the leads, to form what looks like a ladder.

So, if you worked at Zenith assembling radios, there would be rolls of
those ladders for every value of resistor, capacitor, etc, needed, at
each work station.

By the way, there is a good documentary video on youtube that shows
radios being made at Zenith. It was filmed in (If I recall correctly),
the 1950s. Worth watching!

On Saturday, 9 September 2017 20:15:39 UTC+1, wrote:
On Sat, 9 Sep 2017 08:21:13 -0400, "Michael A. Terrell"
wrote:
wrote:

I've always wondered how they paint on the colored stripes. I put "how
do they paint the stripes on resistors" on google, but all I got was
links explaining how to READ color codes.

Has anyone ever heard anything about this process?

Isn't it obvious? Early resistors were hand painted, then they
developed machines for the job.

It's a no brainer they use a machine. My question goes much deeper. How
does the machine do it? Are the paints applied by a paint brush, or
something like a felt tip marker, or maybe some sort of spray method?

You really think a spray would be a good match for this app?

Once the correct colors are chosen for that batch of (whatever value),
how do they rotate them

seriously?

so the paint is not smeared. I can only assume
they are picked up by their leads, not the body, and somehow rotated by
their leads too.

good luck in life.

We live in a world that can print an M on a small candy, print tens of thousands of devices on a bit of epoxy, and make geared watches with gears (wheels) with pitches measured in microns - and has been doing this in the case of watches for nearly 200 years, and in the case of electronics for well over 60 years. Then, consider the printing technology required for paper money.

So, printing stripes and other markings on devices the size of even an 1/8-watt resistors would be a simple issue.

I would posit a rotating intaglio printer as a relatively simple device with very prices application ability and little slop. And although the print heads would wear, they would have very nearly infinite life as compared to a brush or roller. This is the purest speculation, of course.

Peter Wieck
Melrose Park, PA

On Sat, 09 Sep 2017 14:53:50 -0700, wrote:


I would posit a rotating intaglio printer as a relatively simple device
with very prices application ability and little slop. And although the
print heads would wear, they would have very nearly infinite life as
compared to a brush or roller.

Intaglio requires very heavy pressures of around 80T/square inch
generated by *very* heavy machinery; much, much heavier than litho or
letterpress which are like balsa toys by comparison. Then you have to
have the right plates. Engraving those plates to an acceptable standard
requires very *considerable* expertise by people who can command pay
grades that elevate them *way* above every other 'manual' worker into a
league of their own.

This is the purest speculation, of
course.

It certainly is. You are right about the simplicity of the machinery,
though.


--
This message may be freely reproduced without limit or charge only via
the Usenet protocol. Reproduction in whole or part through other
protocols, whether for profit or not, is conditional upon a charge of
GBP10.00 per reproduction. Publication in this manner via non-Usenet
protocols constitutes acceptance of this condition.

On 2017-09-09, wrote:
I've always wondered how they paint on the colored stripes. I put "how
do they paint the stripes on resistors" on google, but all I got was
links explaining how to READ color codes.

Has anyone ever heard anything about this process?

I remember when computers used core memory the manufacturers employed
oriental women to string the cores because of their small, nimble hands.
This may be much the same kind of thing.

--
-----------------------------------------------------------------------------
Roger Blake (Posts from Google Groups killfiled due to excess spam.)

NSA sedition and treason -- http://www.DeathToNSAthugs.com
Don't talk to cops! -- http://www.DontTalkToCops.com
Badges don't grant extra rights -- http://www.CopBlock.org
-----------------------------------------------------------------------------

On Saturday, September 9, 2017 at 7:19:46 PM UTC-4, Cursitor Doom wrote:


Intaglio requires very heavy pressures of around 80T/square inch
generated by *very* heavy machinery; much, much heavier than litho or
letterpress which are like balsa toys by comparison. Then you have to
have the right plates. Engraving those plates to an acceptable standard
requires very *considerable* expertise by people who can command pay
grades that elevate them *way* above every other 'manual' worker into a
league of their own.

It does when printing on paper. However, not when printing on solid materials such as glass bottles as a primary example. That requires a fast-cure (usually heat), high-tack ink, and quite light pressure given the speeds involved. Consider the typical direct-printed beer-bottle.

Peter Wieck
Melrose Park, PA

On 9/9/2017 4:47 PM, Roger Blake wrote:
On 2017-09-09, wrote:
I've always wondered how they paint on the colored stripes. I put "how
do they paint the stripes on resistors" on google, but all I got was
links explaining how to READ color codes.

Has anyone ever heard anything about this process?

I remember when computers used core memory the manufacturers employed
oriental women to string the cores because of their small, nimble hands.
This may be much the same kind of thing.



Not any more. They now have to use a proportional share of big, hairy,
burly men. They throw those misprinted resistors out. Haven't you
noticed the price increases?

On Sat, 9 Sep 2017 14:53:50 -0700 (PDT), "
wrote:

I would posit a rotating intaglio printer as a relatively
simple device with very prices application ability and
little slop. And although the print heads would wear,
they would have very nearly infinite life as compared
to a brush or roller. This is the purest speculation,
of course.

May I humbly suggest you reconsider your speculation. Intaglio is
slow. It works well for flat objects but not so well with irregular
diameters, such as metal film resistors:
https://www.google.com/search?q=film+resistor&tbm=isch
Notice the irregular diameter and inconsistent bulges at the ends
cause by dipping and turning the resistor (before marking) in some
kind of insulating coating before firing. Dealing with these
inconsistencies and irregularities probably eliminates any form of ink
tranfer that involved physical contract with the resistor body such as
roller, brushes, stamping, etc. My guess(tm) is some kind of ink jet
or spray marker applied while spinning the resistor around its center
line. I haven't found any machinery yet that claims to do this.


--
Jeff Liebermann
150 Felker St #D http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann AE6KS 831-336-2558

On Sat, 9 Sep 2017 12:45:58 +0800, Rheilly Phoull
wrote:

On 9/09/2017 10:11 AM, wrote:
I've always wondered how they paint on the colored stripes. I put "how
do they paint the stripes on resistors" on google, but all I got was
links explaining how to READ color codes.

Has anyone ever heard anything about this process?


They get the christmas elves in the off season to paint them on with
their toy decorating brushes.
That's not true. There are no such things as elves. Only faries.
ERS

On 9/10/2017 4:19 PM, wrote:
On Sat, 9 Sep 2017 12:45:58 +0800, Rheilly Phoull
wrote:

On 9/09/2017 10:11 AM, wrote:
I've always wondered how they paint on the colored stripes. I put "how
do they paint the stripes on resistors" on google, but all I got was
links explaining how to READ color codes.

Has anyone ever heard anything about this process?


They get the christmas elves in the off season to paint them on with
their toy decorating brushes.
That's not true. There are no such things as elves. Only faries.
ERS

Then who the hell makes the cookies?

On Sun, 10 Sep 2017 20:19:43 -0400, Tom Biasi
wrote:

On 9/10/2017 4:19 PM, wrote:
On Sat, 9 Sep 2017 12:45:58 +0800, Rheilly Phoull
wrote:

On 9/09/2017 10:11 AM, wrote:
I've always wondered how they paint on the colored stripes. I put "how
do they paint the stripes on resistors" on google, but all I got was
links explaining how to READ color codes.

Has anyone ever heard anything about this process?


They get the christmas elves in the off season to paint them on with
their toy decorating brushes.
That's not true. There are no such things as elves. Only faries.
ERS

Then who the hell makes the cookies?

Trolls make the cookies, but only the "Troll House" brand.

It has been over 50 years since I worked at the Fairchild diode plant.
Our diodes were in the DO-7 packagen and most were striped marked. I
can't remember the fine details of the machine that was used as I was
not directly involved. The diodes were fed on to an approx 3" diameter
with notched on the circumference every, 30 or so degrees. Before that
there was an ingenious device that oriented them for polarity. The
marking was to be towards the cathode end. There were 3 or 4 wheels
that tapered to the width of the intended line. Each of these wheels
ran nto a paint pot with the appropriate color. The diode rotated in
the notch on the 3" wheel and against the paint wheel, went one ot two
notched past for a semi fast dry and fell into a bin. Sorry I don't
have a better memory.
CP

On Tue, 12 Sep 2017 19:50:34 -0700, MOP CAP wrote:

It has been over 50 years since I worked at the Fairchild diode plant.
Our diodes were in the DO-7 packagen and most were striped marked. I
can't remember the fine details of the machine that was used as I was
not directly involved. The diodes were fed on to an approx 3" diameter
with notched on the circumference every, 30 or so degrees. Before that
there was an ingenious device that oriented them for polarity. The
marking was to be towards the cathode end. There were 3 or 4 wheels
that tapered to the width of the intended line. Each of these wheels
ran nto a paint pot with the appropriate color. The diode rotated in
the notch on the 3" wheel and against the paint wheel, went one ot two
notched past for a semi fast dry and fell into a bin. Sorry I don't
have a better memory.
CP

That makes sense and the wheels would rotate the diode, resistor, etc. I
did assume the paint was very fast drying. How they managed to get the
correct polarity with that device is hard to imagine. I can only guess
there was a means to get a meter reading on them in mass amounts.
Interesting stuff!!!!

To measure the BV[ break down voltage] of a diode you apply a small
current [5 micro amp] and measure the voltage.
If it is a high voltage it is in one polarity. If a low voltage it is
the forward direction. If correct the diode drops down. If not it goes
thru a tube that rotates i it n the correction direction and into the
hopper for the painter..
CP

Taxed and Spent wrote:
On 9/9/2017 5:21 AM, Michael A. Terrell wrote:
wrote:
I've always wondered how they paint on the colored stripes. I put "how
do they paint the stripes on resistors" on google, but all I got was
links explaining how to READ color codes.

Has anyone ever heard anything about this process?

Isn't it obvious? Early resistors were hand painted, then they
developed machines for the job.





how did they paint the machines?


They waited until they were completely built, you silly rabbit!


--
Never **** off an Engineer!

They don't get mad.

They don't get even.

They go for over unity! ;-)

wrote:

One thing I do know, is that most small electronic parts with wire
leads, leave the factory in the form of ladders. Meaning that 100 or
1000, or any other number of them are one long strip being held
together by 2 strips of paper around the leads, to form what looks
like a ladder.


Then you don't know anything.


So, if you worked at Zenith assembling radios, there would be rolls of
those ladders for every value of resistor, capacitor, etc, needed, at
each work station.

The proceed is called Tape + Reel, or Ammo Pac, but they are for
automated manufacturing. Leaded components are becoming rare, in
manufacturing, since Surface mount far exceeds leaded components, and
have for decades. Hand assembly doesn't use taped components, since it
takes time to remove the tape before a component is installed. Zenith
used odd tube sockets and terminal strips that often used the full
length of the component's leads. The tape's adhesive would cause cold
solder joints.

--
Never **** off an Engineer!

They don't get mad.

They don't get even.

They go for over unity! ;-)

wrote on 9/9/2017 2:14 PM:

I do believe the early resistors, especially those ceramic types that
had colored dots on them, were probably hand painted. I have also noted
that the old bumble bee caps often had irregular stripes, where the
paint was thicker in spots, thinner in others, and the edges were not
always precise.

Don't know about resistors being hand painted as that sounds expensive. But
I know mica caps used look hand painted and in searching I found one style
that is clearly hand painted.

--

Rick C

Viewed the eclipse at Wintercrest Farms,
on the centerline of totality since 1998

On 09/09/2017 03:11, wrote:
I've always wondered how they paint on the colored stripes. I put "how
do they paint the stripes on resistors" on google, but all I got was
links explaining how to READ color codes.

Has anyone ever heard anything about this process?

Resistors are made from a clay-like material containing carbon or other
conductor in various amounts. Colourants are added, and the material is
rolled and layered into large 'pats', so for example a 4k7 resistor pat
might have cream, yellow, cream, violet, cream, red, cream, gold, cream
coloured layers. This is rolled to the correct thickness corresponding
to the final resistor length, then hollow punches form the resistor
bodies, usually several thousand from one pat. The better quality ones
are rolled for smoothness and low noise. The wire ends are fitted, the
resistors are baked and often varnished. For high accuracy resistors,
the depth of one wire end is adjusted on test before the baking stage.

Cheers
--
Clive

And I was under the delusion that the stripes were painted onto the resistors by tiny trained cockroaches wearing fashionable berets.

On Wednesday, January 3, 2018 at 1:28:00 PM UTC-5, Terry Schwartz wrote:
And I was under the delusion that the stripes were painted onto the resistors by tiny trained cockroaches wearing fashionable berets.

https://pleatedjeans.files.wordpress...oach-large.jpg

Not so fashionable.

Peter Wieck
Melrose Park, PA

I explained once how stripes on DO-7 [about mid-way between a 1/4w and
1/2w resistors] diode bodies were painted.
You have paint troughs with the colors in use, each has a roller the
width of of the trough, against this you have a roller that tapers to
the width of the band. These in turn roll against a larger rubber wheel
and deposits the paint. This in turn rolls against the R or D.


On diodes the bands also indicated the polarity, so there was an
ingenious way to orientate them.
To measure the breakdown voltage of a diode you apply a small [5
micoamp current]. The diodes were fed into a slot, the current was
applied, if you measued a low voltage it dropped straight down.
If you measured a high voltage it went out the side into a tube that
brought it 180 deg. into the proper orientation.
CP

On Wednesday, 3 January 2018 16:11:52 UTC, Clive Arthur wrote:
On 09/09/2017 03:11, wrote:
I've always wondered how they paint on the colored stripes. I put "how
do they paint the stripes on resistors" on google, but all I got was
links explaining how to READ color codes.

Has anyone ever heard anything about this process?

Resistors are made from a clay-like material containing carbon or other
conductor in various amounts. Colourants are added, and the material is
rolled and layered into large 'pats', so for example a 4k7 resistor pat
might have cream, yellow, cream, violet, cream, red, cream, gold, cream
coloured layers. This is rolled to the correct thickness corresponding
to the final resistor length, then hollow punches form the resistor
bodies, usually several thousand from one pat. The better quality ones
are rolled for smoothness and low noise. The wire ends are fitted, the
resistors are baked and often varnished. For high accuracy resistors,
the depth of one wire end is adjusted on test before the baking stage.

Cheers

You're surely pulling someone's leg.


NT

A lot of cookies that come from Elmhurst Illinois where Keebler used to be now say something to the effect of being partially made with genetic engineering. Famous Amos was apparently drawn into this conglomerate at an earlier date.

I no longer see mention of either the Keebler Elves or Amos when I see baked goods from Elmhurst nowadays. Im sure they are all safe, but I still have this nagging image in my mind of an elderly Amos and elves who never age, caged in a laboratory, surrounded by people in white coars & safety glasses. Then I wake up and realize it was all a bad dream.

I think I know a guy who used to work for a resistor company. Ill ask him (his name is mit Mr. Resistor) about the painting and hope he doesnt tell me this quest is futile.

I just caught one of own touchscreen typos - I meant to say his name was NOT Mr. Resistor, but I typed mit.

Now I have to call him Mr. Resistor to protect my source.

He confirmed they did indeed use a striping machine that applied paint with some kind of brush as the component body was rotated. He said they also painted stripes helically on wire that was rotated to achieve the spiral path on the insulation and it then followed a path about 12 feet long vertically to give it time to dry.

I wonder if there is a carbon composition resistor mil-spec still out there on the internet that says anything more than requirements for color accuracy and durability.

Obsolete info, but you can download MIL-R11G from everyspec.com and look at paragraph 3.22. That will reference MIL-STD-1285, marking of electrical and electronic parts, also old info, but you have to start somewhere. Rev. B is the largest document so dont look at the tiny later updates as they are missing the bulk of the details.

This will tell you very little other than that they arent supposed to be smeared and maybe standards for colors. You may find other references to pursue, but there are many other interesting things in there.

Or you become overwhelmingly bored and start to appreciate why the elves get grumpy, sleepy, dopey, etc.

If you pay for premium resistors you get numbers instead of colors.

wrote:

On Wednesday, 3 January 2018 16:11:52 UTC, Clive Arthur wrote:
On 09/09/2017 03:11, wrote:
I've always wondered how they paint on the colored stripes. I put "how
do they paint the stripes on resistors" on google, but all I got was
links explaining how to READ color codes.

Has anyone ever heard anything about this process?

Resistors are made from a clay-like material containing carbon or other
conductor in various amounts. Colourants are added, and the material is
rolled and layered into large 'pats', so for example a 4k7 resistor pat
might have cream, yellow, cream, violet, cream, red, cream, gold, cream
coloured layers. This is rolled to the correct thickness corresponding
to the final resistor length, then hollow punches form the resistor
bodies, usually several thousand from one pat. The better quality ones
are rolled for smoothness and low noise. The wire ends are fitted, the
resistors are baked and often varnished. For high accuracy resistors,
the depth of one wire end is adjusted on test before the baking stage.

Cheers

You're surely pulling someone's leg.
Oh yes, I'm sure of it! All the resistors I've used in the last 30 years or
so had a ceramic core, with ends fuest to the core, and then either metal
film or carbon film deposited onto that. Then, they use an air/abrasive
just to cut a helical groove in the film for higher resistance values.
Then, they are painted overall with that manufacturer's base color (often
tan or light blue) and then the color code is applied. I'm guessing they
have a machine with a row of some kind of rollers each with the right paint
color, and they paint all the stripes in one pass. But, I've never seen
pictures of such a machine.

If they were made as described above, the color would go all the way through
the resistor. I've broken enough over the years to know the inside is
always white for film resistors, and black for carbon composition.

Jon

On Thursday, 4 January 2018 22:14:06 UTC, Jon Elson wrote:
tabbypurr wrote:
On Wednesday, 3 January 2018 16:11:52 UTC, Clive Arthur wrote:
On 09/09/2017 03:11, wrote:
I've always wondered how they paint on the colored stripes. I put "how
do they paint the stripes on resistors" on google, but all I got was
links explaining how to READ color codes.

Has anyone ever heard anything about this process?

Resistors are made from a clay-like material containing carbon or other
conductor in various amounts. Colourants are added, and the material is
rolled and layered into large 'pats', so for example a 4k7 resistor pat
might have cream, yellow, cream, violet, cream, red, cream, gold, cream
coloured layers. This is rolled to the correct thickness corresponding
to the final resistor length, then hollow punches form the resistor
bodies, usually several thousand from one pat. The better quality ones
are rolled for smoothness and low noise. The wire ends are fitted, the
resistors are baked and often varnished. For high accuracy resistors,
the depth of one wire end is adjusted on test before the baking stage.

Cheers

You're surely pulling someone's leg.
Oh yes, I'm sure of it! All the resistors I've used in the last 30 years or
so had a ceramic core, with ends fuest to the core, and then either metal
film or carbon film deposited onto that. Then, they use an air/abrasive
just to cut a helical groove in the film for higher resistance values.
Then, they are painted overall with that manufacturer's base color (often
tan or light blue) and then the color code is applied. I'm guessing they
have a machine with a row of some kind of rollers each with the right paint
color, and they paint all the stripes in one pass. But, I've never seen
pictures of such a machine.

If they were made as described above, the color would go all the way through
the resistor. I've broken enough over the years to know the inside is
always white for film resistors, and black for carbon composition.

Jon

Quite. Even in the carbon comp days they weren't made that way.


NT

The clay ones sound like the process used in the Lascaux process circa 15000 BC �