How to electropolish aluminum----make money online

hey everyone I've been developing a

technique to electro polish aluminum

I haven't found much on the internet

regarding this technique so I thought

I'd share what I've learned this is an

unknown aluminum alloy and as you can

see I have electric polished it here and

this is the stock finish this is another

bar this is known to be 6061 aluminum

and the finish right in this area here

is the mill finish that comes on the

metal you know as I bought it from

McMaster and as you can see even without

any mechanical polishing whatsoever you

get this nice finish here so let me tell

you about it you don't need much exotic

equipment to electro polish alamin 'm

I'm going to show this method with just

pure phosphoric acid and you can get

this on eBay it's actually not even that

expensive and a thermometer a glass or

plastic vessel that can hold about 100

degrees C or less liquids then you need

something heat up the solution I'm going

to use this immersion heater but you

could also use a hot plate or a stove or

something with a heat spreader like that

you need an aquarium air pump and an air

stone or a pump inside the vessel that

can swirl the liquid around it creates

majid ation and a standard car battery

charger for a power supply of course if

you have better equipment you'll get

better process control so if you have a

bench supply that can do constant

voltage and constant current control

it'll be better if you have a heat

controlled hot plate it'll be better but

this is sort of the basic minimum set of

equipment this is 75% phosphoric acid

and in comparison to other concentrated

acids it's actually not such a dangerous

thing to handle but you'll still want to

use gloves splash protection and eye

protection so I'm going to pour out

about half a beakers worth in fact if

you're doing this on larger parts you'll

want to have a much larger container of

acid just to keep the temperature more

stable just to demonstrate this

technique I'm just going to use a small

amount of acid here I'm going to put the

immersion heater in the acid and then

add this thermometer here and we're

targeting about 75 degrees Celsius okay

we're at temperature so I'm going to

take the thermometer out

and add to scrap pieces of stainless

steel and these will form half of our

circuit I'll connect these together

electrically with an alligator clip

okay I've got the air pump turned on and

I'm going to put the air stone in there

and then use a clip to hold it to keep

it from floating I've got the battery

charger on and the negative side

connected to the two stainless plates

that are there I'll connect the positive

side to the piece that we want to polish

and then add that to the bath and make

sure of course that it doesn't short out

okay after just a few minutes let's see

what we've got here I'm going to use

some distilled waters to get the acid

off right away

as you can see it's done a really good

job of polishing it already in just a

few minutes here's the piece we just

polished and you can note a couple

things about it one is that the part of

the metal that wasn't submerged actually

got a little damaged from the acid

spraying on it so you can't halfway

submerged parts that you want to electro

polish you pretty much have to submerge

the whole thing second there is a bit of

pitting going on in here you can see

there's sort of a rough surface and it's

actually a little bit better here near

the surface but down here or the surface

of the polishing solution but down here

there's this pitted texture this is

probably caused by the electrochemical

action of the polishing bath and I'll

show you why that is in just a minute

I was able to find a chart on the

internet that helped explain some of the

results that I was getting this shows

voltage on the y-axis and current

divided by area that's the area of the

part that we're going to polish on the

x-axis and there's three distinct zones

that are identified by the slope of the

of the curve so in this first region

it's mostly linear but then there's a

dip in a relatively flat region and then

it takes off over here and so what's

happening is that in this sort of low

current region over here what we

actually are doing is etching the

aluminum not polishing it and this

happens because the etching takes place

preferentially at these grain boundaries

and what happens is we just end up

digging into the material a little bit

if we increase the amount of current per

unit area what happens is this is

complex and I actually don't fully

understand it myself but the solution

will form a viscous layer on top of the

surface and this actually has the effect

of reducing bumps and so if there were

if there was a sharp edge sticking out

of the part you know a little burr then

that burr is exposed on more sides than

all these other flat regions are and so

it gets preferentially beaten down

polished away because it has more

surface area on this little spot and the

density of the fluid and the

concentration of the electrolyte and the

base metal and the voltage and

everything basically affects this whole

thing of course I tried to collect data

that looked like this graph and set my

oscilloscope up to to try to generate

this but

I couldn't do it so I don't know if this

applies to specific blends of

electropolishing solutions most of the

patents and other information that I

found on the Internet

did not suggest using pure phosphoric

acid they almost always suggested blends

of sulfuric and phosphoric and sulfuric

and ethylene glycol and all kinds of

other things and I tried lots of those

blends and still was never able to

produce a graph like this but anyway the

reason that we were seeing pitting like

this over here is because it much higher

current densities there's a lot of gas

produced and if a gas bubble is on the

surface it can't be electro chemically

polished because there's a big gas

bubble in the way there's no liquid

making contact so you can't go too fast

basically because you're limited by this

hydrogen production problem one thing

that helps is adding a little bit of

surfactant to the polishing solution and

I forgot to mention earlier that you

could put a drop of dishwashing liquid

in there just to lower the surface

tension and help these bubbles break

away from the surface more easily to sum

up the recipe that I recommend is 75%

phosphoric acid at 75 degrees C and you

want to use about a hundred milliamps

per square centimeter and conveniently

this comes out to be just about right

for battery charge or voltage now kind

of in the neighborhood of 14 volts or so

okay see you next time bye best way to earn money from home, make instant money online absolutely free, trusted online money making sites, online income site, best online earning, money online, earn money from home, earn dollars online, earn money online, earn money online 2019, earn money online by typing pages, earn money online daily, online work at home and earn money, online earning, earn money online free, online money earning sites, earn real money online, e commerce ideas to make money, easiest way to earn money online, best way to earn money online, make money from home, make money online free, money making sites, earn from home, real ways to make money from home, online income ideas, make real money online, top online earning websites, earn money online fast,