Greetings All,

Before I tell the story, here's a link to the results:
http://lerch.no-ip.com/atm/Projects/Anodize/

I was wandering thru the local hardware store when I found a bottle of
concentrated sulphuric acid, which happened to be labeled as "Drain
Cleaner"...... I chuckled a little as I thought to myself "That's not
drain cleaner, that's anodizing electrolyte"

Anyway, I picked up my quart of sulphuric acid, and a liquid bottle of
"RIT" black dye, inconveniently labeled as fabric dye.

Back at the house, I filled a 1 gallon plastic bucket half way with
tap water, and stuffed an aluminum baking tin down one side of the
bucket and attached it to the ground leg of my batter charger.

Next I added the electrolyte (maybe a pint) to the gallon bucket half
full of water. The decision on how much electrolyte to add was based
solely on the feeling of unrest that came as the bucket of solution
started getting REALLY warm (maybe 120F).

After that I took this little aluminum threaded web cam adapter I made
in the morning, and attached it to a piece of aluminum filler wire.
The threaded adapter and filler wire went into the ultra-sonic cleaner
for a few minutes while I went and re-read the instruction for
anodizing I found on the web.

About 10 minutes later, feeling full of confidence, I pulled the part
of the ultra-sonic cleaner and gave it a quick tap water rinse. Then
I hung the part in the still rather warm bucket of electrolyte, and
connect the positive cable of the battery charger to the aluminum wire
holding the part.

With a little trepidation, and the 12v batter charger on the 10 amp
setting, I plugged in the battery charger. Both the part and the
aluminum attached to the ground leg starting "Fizzing", and the
battery charger gauge was pegged (BTW, the battery charger lacks an
actual amp gauge, but instead has a silly gauge that instead of being
labled in amps, is labeled in percent battery charge)

At this point, I know I'm doing something, but the question is how
long should I let this run? In my research I've read conflicting
answers to this question. Some sites said 10-15 minutes for small
parts. Other sites said to let it run until the current flow pretty
much stops, as the aluminum oxide which makes the anodizing coating is
non conductive, so a fully formed coating shouldn't conduct..

Not knowing how long to let the process run, I went with the "More is
better" theory and let it run till the current dropped off and the
bubble formation was nearly non existent.

While the part was "Cooking", I went and mixed up the dye solution. I
used about 1 quart of water to half a bottle of dye. (again, staying
true to the "More is better" theory)

It took about 40 minutes for the part to "cook" completely, IE very
little current flow, and very little bubble formation. I then removed
the part, and gave it a cold water rinse. At this point the part had
a gray / green tint, and lost ALL the luster it had prior to being
"Cooked"

After the rinse, I put the part in the dye solution, and stirred it
around a few times. About 10 minutes later I pulled it out, and it
hadn't really changed color. So I let it set for another 10 minutes,
still no color change. Having read that some alloys of aluminum need
a little heat to help the dye penetrate, I gently warmed the dye on a
hot plate, and let the part soak for about 30 minutes.

30 minutes later I pulled the part out of the now warm dye solution.
Now I had a speckled black part, but mostly it was unchanged.
Thinking that since a little heat helped, more heat should help even
more, so I turned the hot plate up.

Now I had the part sitting in a gently boiling solution of black dye,
which thankfully I had the fore thought to do out in the shop,
especially about the time the dye foamed up like boiling milk and
attempted to make a mess out of my already messy shop.

After another 30 minutes of bouncing around in the boiling dye
solution, the part pretty much looked the same as it had earlier, so I
turned the heat off, and wondered where I'd gone wrong.

As an experiment I found a scrap piece of aluminum angle laying on the
floor, and decided to try anodizing it. This time however, I decided
to only "Cook" it for 10 minutes. Amazingly this scrap piece came out
nearly perfect, as seen in the pictures!

So the question is, why did my threaded web cam adapter fail?

Here' my current thinking, which I hope to explore tomorrow after
cleaning the part up on the lathe.

#1 The electrolyte solution was rather warm when I hung the part in
it. perhaps the warm electrolyte was sealing the part as the anodizing
coating was being made. By the time I tried coating the scrap piece
of angle, the electrolyte solution was nearly room temperature.

#2 I "Cooked" the part too long. 40 minutes may have been WAY too
much, and perhaps caused most of the pores in the anodizing layer to
become too small to accept the cheap dye I used.

#3 The unknown alloy I used to fabricate the threaded part may not
like the anodizing process, or the selection of dye I used.

#4 Some combination of the above.

BTW, the wire brush marks near the threads on the web-cam adapter were
done after the part had been boiling in the dye for 30 minutes. For
some reason the dye sort of "Chunked up" on the sides with the
threads. I couldn't wipe the chunks of dye off, so I tried it with
the wire brush, which knocked the big stuff off...

BTW #2, I hope and pray that I can make the web cam adapter look as
good as that stupid piece of scrap I did, because I'm amazed how well
that piece of scrap turned out!

BTW #3, as an experiment, I tossed a piece of the same scrap angle
into the dye, without "Cooking" it first, and the dye just wiped off
afterwards.

In any event, It was a pretty good way to spend a day off





Take Care,
James Lerch
http://lerch.no-ip.com/atm (My telescope construction, Testing, and Coating site)

Press on: nothing in the world can take the place of perseverance.
Talent will not; nothing is more common than unsuccessful men with talent.
Genius will not; unrewarded genius is almost a proverb.
Education will not; the world is full of educated derelicts.
Persistence and determination alone are omnipotent.
Calvin Coolidge

"James Lerch" wrote in message
...
Greetings All,

Before I tell the story, here's a link to the results:
http://lerch.no-ip.com/atm/Projects/Anodize/

Neato!

I was wandering thru the local hardware store when I found a bottle of
concentrated sulphuric acid, which happened to be labeled as "Drain
Cleaner"...... I chuckled a little as I thought to myself "That's not
drain cleaner, that's anodizing electrolyte"

Ah, must be in a red bottle? Or possibly a store brand.

Next I added the electrolyte (maybe a pint) to the gallon bucket half
full of water. The decision on how much electrolyte to add was based
solely on the feeling of unrest that came as the bucket of solution
started getting REALLY warm (maybe 120F).

Yep, sulfuric acid makes a nice amount of heat when dissolved. Taking
precautions, I've tried to make it splatter to see if it happens, but so far
it's just gotten warm, no boiling yet. Given the amount of heat it makes, I
don't doubt it can and will splatter, I just haven't seen it yet.
*shrug*

At this point, I know I'm doing something, but the question is how
long should I let this run?

I would say until the current stops.

Other sites said to let it run until the current flow pretty
much stops, as the aluminum oxide which makes the anodizing coating is
non conductive, so a fully formed coating shouldn't conduct..

Indeed, the same process is used in millions of electrolytic capacitors.
You're using some right now, inside your computer and monitor, indeed they
are almost ubiquitous with electronics. These consist of a coil of aluminum
foil and paper, the paper being soaked with a proprietary electrolyte which
has low resistivity. (Apparently, exact composition is a tightly guarded
industry secret.)

Anyways, these capacitors degrade with time if unused - the oxide layer
decomposes and the voltage rating drops. Instead of throwing them out, you
can "reform" them by applying a small current which anodizes it (slowly so
as not to overheat it). After a long time, maybe a few hours if you are
impatient (depends how hard you push it), it'll be back up to rated voltage.
Electrolytics go up to 500V, you can imagine how thick that anodized layer
must be :-)

Not knowing how long to let the process run, I went with the "More is
better" theory and let it run till the current dropped off and the
bubble formation was nearly non existent.

Fair enough. You can also start at a low voltage, say 1-5V range, and use a
variac or adjustable power supply or steps of voltages to climb up to say 20
to 50V. To make a more consistent deposit you'd want a current-limited
supply: set it to top out at say 30V, supplying a constant 1 or 20 or 50
amperes (for however big your workpiece is) all the while until it gets
there. Consider two things: electrons (and thus current) flow as long as
there is enough voltage to overcome whatever (namely, the oxide layer), and
each number of electrons (namely, something like 26.7Ah per mole, aluminum
needs three) oxidizes a certain amount of aluminum such that it forms the
anodized layer. You can see that 1. it will take a certain number of
electrons to get to a given voltage, and 2. it takes a certain voltage for a
certain total transfer, or whatever.

I would guess hard anodizing is as high as 100V, unless there's a different
chemistry at work in that process. As I said, you can theoretically go up
to 500V, and personally I don't see any reason why you can't go beyond,
except for practical reasons of course.

It took about 40 minutes for the part to "cook" completely, IE very
little current flow, and very little bubble formation.

That long probably isn't necessary, although I doubt it hurts anything. I
once was messing with a similar weak sulfuric acid solution myself,
something I tried was anodizing aluminum, I hooked it up and immediately the
power supply grunted with effort as probably 20-30A flowed through the small
fragment, then within a few seconds, it diminished until I couldn't tell a
difference in the current level, dipping and removing the piece to check.
That was something like 6V.

I then removed
the part, and gave it a cold water rinse. At this point the part had
a gray / green tint, and lost ALL the luster it had prior to being
"Cooked"

Sounds about right.

snip

I can't comment on the dyeing...

Tim

--
"California is the breakfast state: fruits, nuts and flakes."
Website: http://webpages.charter.net/dawill/tmoranwms

James Lerch wrote:
Greetings All,

Before I tell the story, here's a link to the results:
http://lerch.no-ip.com/atm/Projects/Anodize/

I was wandering thru the local hardware store when I found a bottle of
concentrated sulphuric acid, which happened to be labeled as "Drain
Cleaner"...... I chuckled a little as I thought to myself "That's not
drain cleaner, that's anodizing electrolyte"

Anyway, I picked up my quart of sulphuric acid, and a liquid bottle of
"RIT" black dye, inconveniently labeled as fabric dye.

Back at the house, I filled a 1 gallon plastic bucket half way with
tap water, and stuffed an aluminum baking tin down one side of the
bucket and attached it to the ground leg of my batter charger.

Next I added the electrolyte (maybe a pint) to the gallon bucket half
full of water. The decision on how much electrolyte to add was based
solely on the feeling of unrest that came as the bucket of solution
started getting REALLY warm (maybe 120F).

After that I took this little aluminum threaded web cam adapter I made
in the morning, and attached it to a piece of aluminum filler wire.
The threaded adapter and filler wire went into the ultra-sonic cleaner
for a few minutes while I went and re-read the instruction for
anodizing I found on the web.

About 10 minutes later, feeling full of confidence, I pulled the part
of the ultra-sonic cleaner and gave it a quick tap water rinse. Then
I hung the part in the still rather warm bucket of electrolyte, and
connect the positive cable of the battery charger to the aluminum wire
holding the part.

With a little trepidation, and the 12v batter charger on the 10 amp
setting, I plugged in the battery charger. Both the part and the
aluminum attached to the ground leg starting "Fizzing", and the
battery charger gauge was pegged (BTW, the battery charger lacks an
actual amp gauge, but instead has a silly gauge that instead of being
labled in amps, is labeled in percent battery charge)

At this point, I know I'm doing something, but the question is how
long should I let this run? In my research I've read conflicting
answers to this question. Some sites said 10-15 minutes for small
parts. Other sites said to let it run until the current flow pretty
much stops, as the aluminum oxide which makes the anodizing coating is
non conductive, so a fully formed coating shouldn't conduct..

Not knowing how long to let the process run, I went with the "More is
better" theory and let it run till the current dropped off and the
bubble formation was nearly non existent.

While the part was "Cooking", I went and mixed up the dye solution. I
used about 1 quart of water to half a bottle of dye. (again, staying
true to the "More is better" theory)

It took about 40 minutes for the part to "cook" completely, IE very
little current flow, and very little bubble formation. I then removed
the part, and gave it a cold water rinse. At this point the part had
a gray / green tint, and lost ALL the luster it had prior to being
"Cooked"

After the rinse, I put the part in the dye solution, and stirred it
around a few times. About 10 minutes later I pulled it out, and it
hadn't really changed color. So I let it set for another 10 minutes,
still no color change. Having read that some alloys of aluminum need
a little heat to help the dye penetrate, I gently warmed the dye on a
hot plate, and let the part soak for about 30 minutes.

30 minutes later I pulled the part out of the now warm dye solution.
Now I had a speckled black part, but mostly it was unchanged.
Thinking that since a little heat helped, more heat should help even
more, so I turned the hot plate up.

Now I had the part sitting in a gently boiling solution of black dye,
which thankfully I had the fore thought to do out in the shop,
especially about the time the dye foamed up like boiling milk and
attempted to make a mess out of my already messy shop.

After another 30 minutes of bouncing around in the boiling dye
solution, the part pretty much looked the same as it had earlier, so I
turned the heat off, and wondered where I'd gone wrong.

As an experiment I found a scrap piece of aluminum angle laying on the
floor, and decided to try anodizing it. This time however, I decided
to only "Cook" it for 10 minutes. Amazingly this scrap piece came out
nearly perfect, as seen in the pictures!

So the question is, why did my threaded web cam adapter fail?

Here' my current thinking, which I hope to explore tomorrow after
cleaning the part up on the lathe.

#1 The electrolyte solution was rather warm when I hung the part in
it. perhaps the warm electrolyte was sealing the part as the anodizing
coating was being made. By the time I tried coating the scrap piece
of angle, the electrolyte solution was nearly room temperature.

#2 I "Cooked" the part too long. 40 minutes may have been WAY too
much, and perhaps caused most of the pores in the anodizing layer to
become too small to accept the cheap dye I used.

#3 The unknown alloy I used to fabricate the threaded part may not
like the anodizing process, or the selection of dye I used.

#4 Some combination of the above.

BTW, the wire brush marks near the threads on the web-cam adapter were
done after the part had been boiling in the dye for 30 minutes. For
some reason the dye sort of "Chunked up" on the sides with the
threads. I couldn't wipe the chunks of dye off, so I tried it with
the wire brush, which knocked the big stuff off...

BTW #2, I hope and pray that I can make the web cam adapter look as
good as that stupid piece of scrap I did, because I'm amazed how well
that piece of scrap turned out!

BTW #3, as an experiment, I tossed a piece of the same scrap angle
into the dye, without "Cooking" it first, and the dye just wiped off
afterwards.

In any event, It was a pretty good way to spend a day off





Take Care,
James Lerch
http://lerch.no-ip.com/atm (My telescope construction, Testing, and Coating site)

What you need to do is find the process description for decorative
anodizing. There's literally hundreds of different processes. At one
time I ran process control in an anodizing plant where we did
decorative anodizing. IIRC, we tried to keep the concentration of acid
down below 10%, if it got above that, the oxide cells started getting
soft and flimsy and didn't soak up the dye. The temperature had to be
controlled, too, too hot and the same thing happened. We tried to keep
it as cool as we could, usually below 80 degrees, when the chillers or
circulation pumps went down, we were out of business. The dye we used
ran about $50/pound and was specially formulated for the process.
Dying usually took about 15 minutes if the concentration was correct,
pH was important on that bath. After treatment was immersion for about
30 minutes in hot nickel acetate solution, pH was adjusted with glacial
acetic acid. The power supply was a constant current one, topped out
at 10000 amps. A full rack of extrusions usually ran about 6000 amps
if the acid concentration was correct. I have no idea what the voltage
ran, current was what was specified in the process manual, so much per
square foot for each different process. The tank was lead-lined, the
racks were titanium.

Alcoa used to have a book on the different processes, I've seen it on
the shelf in some university libraries.

Stan

On 2 Jun 2005 08:43:13 -0700, wrote:


What you need to do is find the process description for decorative
anodizing.

Last night after posting, I found this site, which is hands down the
best descriptive site I've found to date:

http://www.focuser.com/atm/anodize/anodize99.html


IIRC, we tried to keep the concentration of acid
down below 10%, if it got above that, the oxide cells started getting
soft and flimsy and didn't soak up the dye. The temperature had to be
controlled, too, too hot and the same thing happened. We tried to keep
it as cool as we could, usually below 80 degrees, when the chillers or
circulation pumps went down, we were out of business.

I may be experiencing both problems, too high an acid concentration,
as well as excessive heat.

The power supply was a constant current one, topped out
at 10000 amps. A full rack of extrusions usually ran about 6000 amps
if the acid concentration was correct. I have no idea what the voltage
ran, current was what was specified in the process manual, so much per
square foot for each different process.

I wonder if using my Miller 180SD welder in DC stick mode as a
constant current power source would violate any warranties?

One other question, since I don't know the pedigree of the material I
made that threaded adapter out of, what if it wasn't aluminum, but
actually magnesium? (The two materials are difficult to tell apart,
yes?)




Take Care,
James Lerch
http://lerch.no-ip.com/atm (My telescope construction, Testing, and Coating site)

Press on: nothing in the world can take the place of perseverance.
Talent will not; nothing is more common than unsuccessful men with talent.
Genius will not; unrewarded genius is almost a proverb.
Education will not; the world is full of educated derelicts.
Persistence and determination alone are omnipotent.
Calvin Coolidge

In article , James Lerch
says...

One other question, since I don't know the pedigree of the material I
made that threaded adapter out of, what if it wasn't aluminum, but
actually magnesium? (The two materials are difficult to tell apart,
yes?)

I seem to recall that there are some aluminum alloys that
do not anodize well.

Jim


--
==================================================
please reply to:
JRR(zero) at pkmfgvm4 (dot) vnet (dot) ibm (dot) com
==================================================

On Thu, 02 Jun 2005 05:52:44 GMT,
(James Lerch) wrote:

Anodizing electrolyte: battery acid from NAPA (about $5) diluted 3:1
(or less) with distilled water.

Temperatu cold is better but room temp works OK.

Current: about 30 mA per square inch for about 90 minutes. An
anodize film made at higher current density or higher temperature
doesn't accept dye as well. Voltage is typically about 12 volts but
make it whatever it needs to be to get the current you need. Battery
charger driven by a Variac, electronics bench lab supply or simple
home brew. I use a dirt-simple adjustable current source, email me
if you'd like a schematic. You could build one with $10 worth of
parts from Radio Shack. Then you don't need a variac -- or a handful
of fuses for when (not if) you get shorts and blow the fuse in
your multimeter being used to measure current.

Be sure you have a good tight connection that will stay connected for
the duration.

After anodizing, check work with an ohmmeter. It should show no
conductivity.

Dye: RIT works OK for most colors except black. For black, best
results are had with real anodizing dye. It's available in small
qty from Caswell Plating and perhaps elsewhere. Dye at 140F for
20 minutes or so.

Seal: just boil in distilled water for 30 minutes or so. There are
sealants available, but just boiling in water seems to work OK.

On 2 Jun 2005 08:43:13 -0700, wrote:

,;
,;
,;James Lerch wrote:
,; Greetings All,
,;
,; Before I tell the story, here's a link to the results:
,; http://lerch.no-ip.com/atm/Projects/Anodize/


a whole bunch of stuff deleted

I posted this URL in 2001. It is still active and has good info on
anodizing aluminum.

http://www.focuser.com/atm/anodize/anodize.html

"James Lerch" wrote in message
...
snip--------

One other question, since I don't know the pedigree of the material I
made that threaded adapter out of, what if it wasn't aluminum, but
actually magnesium? (The two materials are difficult to tell apart,
yes?)

No, not really. Magnesium is much lighter and machines totally differently.
It crunches as it cuts, and is quite abrasive, dulling HS tools fairly
quickly. 7075-T6 aluminum displays similar machining qualities, but even
it can be discerned from magnesium once you've machined it.

From your description, I think what you did was hard anodize your part. The
color is a dead give-away. As far as I know, it won't accept a dye finish,
regardless of your attempts. Check it with a file on a corner that isn't
critical and see if it files. Hard anodizing is much harder than a file, so
it won't touch it.

Gorton used to hard anodize the drive pulleys on their mastermils, the
bottom of which was also the spindle brake. They'd run for years in an
industrial setting before needing to be turned and re-anodized. Hard
anodize, unlike other anodizing, can be applied quite thick, and from your
description of the amperage falling off, I think that's exactly what you
accomplished.

I'd love to hear the results of the file test, assuming you're willing to
perform it.

Harold