Bella ragazzi! This evening we're going to speak about ANODIZING Anodizing is a chemical / electrochemical treatment made principally on aluminium at industrial level, and it serves because with anodizing we create a layer of aluminium oxyde, alumina, which is a very hard material,
hardness of 9 on the Mohs scale similar to corundum This is done to strengthen the external surface and this creates a layer of protection against atmospheric agents and wear of the piece. We like anodizing because in addition to protecting the material, we can also color the part! So we like these red, blue, green, purple colors. Today we will show you so
simple and practicable by everyone how to do it You will find dozens of videos on this topic but unfortunately none of them are clearly explained We will try, starting from the bases So that everyone can choose the treatment they prefer Okay, let's start with the aluminum block, which is this normally it protects itself, through atmospheric oxygen, with a very thin layer of 40 Ångstrom (a thickness invisible to the naked eye) of aluminium oxide this helps the aluminum to remain shiny and don't become rusty like iron.
With anodizing practically We create, through some pores
that there are on the surface of this oxide, some deepest holes that sink deeper and deeper into metal creating a honeycomb structure like this. So here we have here our aluminum block and this thick layer of oxide it allows the coloring by introducing inside these pores the dye. So, based on the
current that we will apply, these pores they can be very tight, like these,
and therefore we will have a more resistant surface or we could have a surface like this which will be weaker, but will allow for better coloring So let's proceed to anodize and color something! You saw this carbide lamp in video number #184, we will color this aluminum cap. The first procedure is
to mechanically clean the part, in our case it is already quite clean but we recommend brushing it, of
degrease it above all very well to prevent stains from remaining on the anodized part Now we will prepare a sodium hydroxide solution We always use distilled water it costs very little and if you have a dryer You can use the water produced by that, after filtering it You will however find all the links in the description We use 10 grams of sodium hydroxide for every 100 milliliters of water So let's weigh 10 grams of sodium hydroxide this process will be used to pickle the surface Always be careful that adding
caustic soda quickly to the water this produces a lot of heat. In fact we use this water which we normally keep in the refrigerator, to avoid this thermal increase We can also measure it It is now at 12 degrees Celsius, but slowly it will rise We repeat saying that precisely the cleaning
of the piece is fundamental, therefore from now on or we'll fix it here and not
we will never touch our hands until the end of treatment. And now
we leave it bath in water and sodium hydroxide from 2 to 5, to 10 minutes.
If instead you already have an anodized part and you want to take away the anodizing; for example you have a red part and you want to make it blue,
you can leave it to soak in water and sodium hydroxide and the previous anodizing will go away Now let's pause for a moment and then
we will come back later when the piece is ready. Okay, it's been 5 minutes any type of aluminum alloy
takes a different color inside sodium hydroxide; for example this should be Ergal, so it takes this color a little black, do not be frightened, because
there is nothing of strange: there is magnesium, there are other metals, so it takes this
color. As soon as we introduce it in sulfuric acid it will resume its
natural aluminum color. here it is that it has now turned black
but it is not the coloring of the anodizing it's just a small layer of
oxide that has formed. We rinse very well in distilled water, leave it there, and in the
meanwhile we prepare the Nutella jar for anodizing You need a glass container or very thick plastic container because, working with sulfuric acid, it is preferable to have a robust container We cut a strip of lead from this which is a lead that is used in Germany for windows or doors You will find an equivalent product in the video description In this anodizing jar
you can use lead or aluminum as cathodes however it is necessary to use pure aluminum if you don't find 2 sheets of pure aluminum you can also use aluminum foil folding it several times. Ok, this is our cathode, the negative pole. Now let's see: these types of anodization exist in a main way: we talk about 5 microns thickness only for aesthetics so if we just have to
coloring a decorative object. 10 microns thick for indoor applications 15 microns thick for outdoor applications;
rain, sun etc. 20 microns thick for more aggressive atmospheres, such as smog, sea salt, etc. Near the sea there is a more aggressive atmosphere for aluminum 25 microns thick for architectural structures In short, the greater the thickness of the anodizing, the greater the surface protection. We have already prepared the sulfuric acid solution because we need it cold (remember that mixing acid and water produces heat) Contains 170 grams of pure sulfuric acid in 1 liter of water Remember that acid must be added to water and not vice versa otherwise a great deal of heat would form, splashes of acid everywhere, in short, a very dangerous situation would arise Always wear gloves and glasses
when you handle these substances!!! If you don't remember "the acid and water thing" then remember the phrase: "You should never give a drink to the acid " Now we need the formula to calculate the current density you've probably heard of rule 720 but here in Europe we use metric measurements so we did a conversion.the thickness of oxide that will be formed (in microns) is obtained with this formula: 0.03 multiplied by the time in minutes in which we will do
the treatment, multiplied by the current density in milliamps on square centimeter.
And now, slowly we will go to see in detail The inverse formula, because
what we need is current density, it's this one. So, the conditions
typical of this treatment vary from 10 to 60 minutes, however you can also do
even 7/8 hours treatments that will be much much more precise;
currents ranging from 10 to 20 milliamps to square centimeter and you get
thickness, with this treatment with sulfuric acid, from 5 to 35 microns; therefore even much higher than those used in the industrial processes. Then we'll show you the ink too.
So, let's take this part here, let's go get it
a caliper and we do the surface calculations. Ok then we measured the
our piece and we calculated its surface, which turns out to be 8
square centimeters. So now let's go do the math: in this case we have decided to make an anodization that
lasts a long time, about 50 minutes, why? because normally the piece, when it comes
anodized, it produces a lot of heat too; the heat goes to "eat" the layer
of oxide that we have just formed! So 2 things are very important: the
first fundamental is that the temperature of our acid-based electrolyte
sulfuric never exceeds 21 degrees Celsius.
The second is precisely that the piece does not heat up. However
which for small pieces like these, a screw, a small detail,
we can confidently trust the thermal inertia of ours
container that will keep it cold, if you have to make big parts it will be
need to introduce a cooling circuit or or to put the container
in a water bath with some ice so that the temperature stays below
of the due. (21°C) So 0.03 multiplied by 50 is 1.5,
we decide to make a thickness of 10 microns for example. So 10 microns
divided by 0.03 multiplied by 50 we said 1.5 we get a density
6.6 mA current for each square centimeter, so let's multiply
for 8 and we have a current of 53 mA So now let's go to
set our power supply: we can safely bring it to one
voltage of 24 volts, you will see that normally the working voltage
with current limit will remain much lower, we will short circuit and limit
at 53 mA So 400... 300... 200... I don't have a very delicate hand. Here they are, 50 mA!
At this point we connect the negative to our lead strip and
the positive, since we have to anodize, to our part.
Look at the color of the piece that from black will slowly begin to change color
and will resume its natural aluminium color and see what happens in the meantime at the voltage: starting from even half a volt.
Let's go up a bit with the current, which we said 50 mA, as we go
will form the oxide layer will rise the the impedance of this circuit for which
the tension will slowly begin to rise. And now let it pass
these 50 minutes to complete the treatment. Ok now more or more have passed
minus 40 minutes, and as we can see after 2-3 minutes our part has taken on the natural color of aluminum slowly it is anodizing and the oxide layer is forming; If we look at the power supply, we will see that this oxide layer will have made the voltage rise, even reaching 18.6 volts.
Very well, while
this piece ends up anodizing let's prepare our ink. Then,
as ink normally in the videos you see that they use dyes for
clothes like these or even food coloring; they are very, very much
uncomfortable because they are in this format: they are very light powders, they are
pigments and are very difficult to dose so you never get one
homogeneous result: if you want to make ten pieces they come
out of ten different colors, you have to be careful of
concentration, it is not possible to obtain a homogeneous result.
The best solution, which is the one we recommend, also because it is the one on which
we worked harder, is to use this ink for jet printers which also allows you to make the tint of the color you want; so now
we're going to get a computer for a moment and we will also see how to customize our color (you will find the link in the description)
Here we are! So on this site but there are many on the net,
we have the option to convert a color whose shades we know
so what do I know: a 50% of red, now I'm doing a random color, a little bit of green and all blue we have this violet here,
click on "convert" and this program will give us how much color percentage
cyan, which is that classic blue of inkjet printers
it will take, how magenta, how yellow in this case 0, and how much black.
In this way we will go here now one of our colors, one of ours
favorites we called "Blu The Strike" which is a very blue
very intense, very beautiful to look at on aluminium. So there
ink percentage is 6 grams of ink for every 100 milliliters
of water. Our part is small, so we will only use 25 milliliters of water and we will have to make the percentage of each
color on 1.5 grams of ink. (6x0,25) Let's start with cyan here too we recommend you
four syringes: one for each color, so as not to confuse them half a gram... 1.2 grams... 1.3... you don't need absolute precision ok a gram and a half of cyan,
then we need a 10% magenta,
so on a gram and a half we are talking about 0.15 grams, so we take the
magenta (I hope there are no people
emotional with needles...) we do the tare, sorry, here not
we have a flat surface ok 12... 13... 14... 0,15! and this color will have to be worn
at a temperature of 70 degrees celsius so now we're going to set the heater for this magnetic stirrer to a temperature of 70 degrees waiting for time to expire, now
very little is missing.
Well we have now reached the end of ours
50 minutes and at this point we take our anodized piece, we remove more
acid is possible, we rinse it in demineralized water, always advisable
compared to tap water, which may contains salts that could dull
the coloringe.
And at this point we put the part in our ink.
The ink must be around 70°C We will leave it here for 15 minutes so let's set our timer and see you soon. Ok there are still a few seconds, but I would say
that we can already stop at this point
we take out our part and we can already see the coloring it has taken.
At this point we rinse it always in demineralized water and we put it in boiling water from 10 minutes to half an hour.
What happens in this time? Then, we have created, in this case at
constant current, so we will have these walls perfectly parallel, these layers of
oxide, the ink has penetrated inside by capillarity filling
all these channels that we created,
now by putting it in boiling demineralized water or even
you can put it in a stream of steam they will close and seal these
pores, so the ink will remain inside and the light that will hit these
these pores will come out of the shade of the
of the color we have chosen. There are different types of current variations according tothe different types of industrial processes that can form
"V" slots, they can even form slots made like this, trapeze, or
they can even be personalized making almost spheres: in this case
the light that enters will bounce here, pass through our pigment and exit
out this type of treatment is
the one that allows the most color rendering on the part. And now there
we will review in 15-20 minutes when this piece will be
sealed and we will see the final result. Well, it's been 20 minutes now,
the piece is now sealed, we can extract it from the boiling water in this case the demineralized water
no longer needed, but I use it now to to cool the piece and be able to take it with the hands. As you can see it no longer disperses ink. And here is the result!!! Belle ragazzi! Please sign up
at the Kaos La Leggenda channel, you will find all the components to accomplish this
anodizing in your home below in the description of the
video. Have fun and good anodizations!
