# How to Anodise at home



## BradG (Jul 22, 2011)

And so it begins...

The methods i will discuss in this thread are methods i use which work well for me. There are many scientific calculations which can be applied for calculating how much Ampre is required which is determined by the surface area of the work piece, to the temperature of the acid bath along with acid concentrations and voltages.

As all of the parts i anodise are small, i generally just use a 12V 2A power supply.. more on that when we get to it 

*I would also like to point out you are using ACID... so be careful, and please if your not confident on what you are doing, you may want to take a pass on this. please read as much safety information as possible with regards to not only handling Acid but using it safely*

*THROUGHOUT THE WHOLE PROCEDURE YOU SHOULD BE WEARING CHEMICAL RATED GLOVES AND GOGGLES AT A MINIMUM.*

*You also need very good ventilation. what isnt shown in these pictures is the powerful fansucking the air straight outdoors*


*Try and avoid using water which has impurities such as tap water. buy alot of distilled water, you will get through alot of it. use it for rinsing and cleaning your parts, for making up your dye solution and your acid bath. I even use it for boiling the piece sealed at the end.*






You will need a suitable material for making the Cathodes of the tank. (the negative plates) I use Lead flashing. I would advise this as many metals will react in the tank causing undesired results





Here i have a 3L container, with two pieces of lead flashing bent over either side. 





I am using very strong Acid. This is 97% Sulphuric acid, and pretty nasty too. Hence why i am wearing chemical rated gauntlets, a gas mask, and overalls. I would not recommend using Acid this strong unless you are very confident on what you are doing. it needs to be heavily diluted to around 10 - 15% I have added 1800ml of *distilled* water, and 200ml of sulphuric acid







A piece of wire (i used a piece of 6A mains cable as thats what i had laying around) which connects the two pieces of lead together. As you can see in the picture on the right hand side another wire is attached which is the negative of the power supply, which happens to be 12V 2A. This then completes your Cathodes.
For safety, the acid bath is stodd within another container to prevent spillages etc






I have taken a piece of wood which is the width of the outer container, and drilled a hole through the middle of it.
A piece of aluminium welding wire has been passed through and then bent into a V and pushed down the barrel of this pen piece to secure it.

*An additional note*
*The part must be perfectly clean before anodising! Anodising will not hide a poor finish, it will enhance it. a finger print will also show up in the anodised layer from the grease on your fingers effecting the results. Always wear gloves not just for Acid protection, but to keep those prints off your pieces. Soak your pieces in caustic soda for a couple of minutes prior to anodising. this will strip off any dirt. after this place it into a container of distilled water for rinsing and scrub it with a tooth brush, still with your gloves on. when you are sure its perfectly clean, you may start to anodise*






The top half of the aluminium wire is kinked over to prevent the part from slipping down, so that it is freely suspended not touching the sides or the bottom of the container.
I then connect the negative wire of the multi meter to this, and the positive wire of the multi meter to the postive of the power supply.






With the multi meter set to read amps, it will give you a reading of the current being drawn.
When you Anodise you are creating an insulating layer over the piece of aluminium. As this layer gets thicker and stronger the conductivity of the piece will decrease. A general rule of thumb for anodising for good results is about an hour. Alternatively doing it as i have, when the Ammeter shows 250mA, its hardly conducting compared to the value shown in the picture. At this point i would stop Anodising.






An image of the setup running.





After the part has finished anodising, rinse it off in distilled water, and place it into a pan of the dye colour of your choice. I personally prefer to use professional anodising dye as i find it has better lightfast properties and therefore is alot more resiliant to fading. Many however simply use clothes dye. At this point, you will most probably notice the piece has changed in the following pictures! and thats because i had a blunder. Always keep the temperature of the dye solution between 55'C and 60'C ... if it raises higher than this it will begin sealing the oxidised layer before taking up the dye. In my case, the phone rang and i didnt turn off the heat......... well, all's not lost as you can place the piece into Caustic soda for 10 minutes which will strip off anodising! this is also great if you have something you dont like the colour of and would like to reanodise it. simply scrub off after a soak in caustic, and you can start from scratch.





After the piece has been in the dye, drop it into some near boiling water (anything over 95'C) for half an hour, to seal the oxidised layer 





After this, let the piece cool, and take pleasure in admiring your handy work 

Now all whats left for me is to go back and fix the part i messed up in the making of this tutorial.

I hope this has been of use to you guys. I've certainly gained alot of knowledge from these forums and would like to return the favour if i may.


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## mredburn (Jul 22, 2011)

Very interesting thanks for sharing the process.  I look forward to the rest of your processes.


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## renowb (Jul 22, 2011)

Very interesting.


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## BradG (Jul 22, 2011)

Many thanks for the interest 

The part has finished anodising which took around an hour and a half. (another good tell tale sign is that the bubbles stop forming on the cathodes - oh and one other note... The bubbles are hydrogen gas. So no smoking while your doing this, and hence the good ventilation.)

Feeling pretty tired now so its sensible to put my chemistry set away and get some sleep. I will finish off this process when i get home from work tomorrow

Thanks for reading


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## holmqer (Jul 22, 2011)

Just something to add to your tutorial

When diluting acid, pour acid into water, do NOT pour water into acid. Pouring water into acid can cause the water to flash boil and splatter acid.

Also the acid must be poured in very slowly to allow the acid to disperse


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## BradG (Jul 22, 2011)

Indeed Eric, thanks for contributing  AAA - Always Add Acid


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## Dalecamino (Jul 22, 2011)

Glad I found this. Question.....is there a color additive? Blue,red,green? Thanks for doing this Brad. It IS interesting.


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## Zulu (Jul 22, 2011)

*Another question *



BradG said:


> Many thanks for the interest
> 
> The part has finished anodising which took around an hour and a half. (another good tell tale sign is that the bubbles stop forming on the cathodes - oh and one other note... The bubbles are hydrogen gas. So no smoking while your doing this, and hence the good ventilation.)
> 
> ...



Where do you get 97% Sulphuric acid in the UK?
Would "Halfords" stock something like that by any chance?
Good tutorial BTW.
Regards.


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## Thumbs (Jul 23, 2011)

Extra tip:
When pouring acid or other strong reagents to mix or dilute them we used a glass rod to lead the pour to help prevent splashing hazardous material, as well.


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## mredburn (Jul 23, 2011)

SUlpheric acid is used in car batteries. Im not sure about now  but they used to sell replacement acid at the auto parts stores here in the US. It isnt regent strength but your going to dilute it anyway.


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## BradG (Jul 23, 2011)

Zulu, as Mike mentioned you can purchase battery top up acid from auto stores. this is typically 30% strength, so you can dilute it on a 1:1 or a 1:2 ratio
 and works fine for anodising


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## BradG (Jul 23, 2011)

dalecamino said:


> Glad I found this. Question.....is there a color additive? Blue,red,green? Thanks for doing this Brad. It IS interesting.


 
Indeed there is. you could actually use clothes dye for the colouring however there are professional anodising dyes available which is what i use. They seem to have a better resistance to fading and better colour uptake.

I am just about to go off to the kitchen and dye the piece above using black dye. so check back soon for the images


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## Dalecamino (Jul 23, 2011)

BradG said:


> dalecamino said:
> 
> 
> > Glad I found this. Question.....is there a color additive? Blue,red,green? Thanks for doing this Brad. It IS interesting.
> ...


 OK, still waiting!


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## BradG (Jul 23, 2011)

Chuck..... While I was dyeing the part the telephone rang and drew my attention away. The temperature rised to the 80's and in effect sealed the oxidised layer before dye uptake! .... Fools error lol. Il strip that back with caustic soda and repeat tomorrow


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## Dalecamino (Jul 23, 2011)

BradG said:


> Chuck..... While I was dyeing the part the telephone rang and drew my attention away. The temperature rised to the 80's and in effect sealed the oxidised layer before dye uptake! .... Fools error lol. Il strip that back with caustic soda and repeat tomorrow


  Pitty! Unplug that phone:biggrin:


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## BradG (Jul 24, 2011)

There you go guys. the first post has been updated to show the whole process


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## Dalecamino (Jul 24, 2011)

Very nice Brad. Thanks for your efforts.


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## thewishman (Jul 24, 2011)

Thanks for all of the photos and commentary! That is a lot of work to put together. I love to learn new things and have been curious about anodizing - you made my day. (Who would have thought you'd use anodes to anodize?)


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## BradG (Jul 24, 2011)

You're Welcome Chuck & Chris. Glad to be of help 

Here is a picture of both the pieces anodised loosely slotted together prior to being assembled. hence why it looks like the clip is about to fall off


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## Dalecamino (Jul 24, 2011)

Very nice Brad. I had intended to say so in my last post. But, being pressured to get off the computer to take Susanne to get her hair fixed, cut me short. Looking forward to more anodized pens.


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## BradG (Jul 25, 2011)

No issue at at all Chuck, got to keep those happy at home!


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## HermosaGuy (Jul 26, 2011)

Thanks for the great tutorial.  I gotta ask how do you dispose of the used solutions?


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## BradG (Jul 26, 2011)

They can be flushed down the toilet when your done with them, but remember they last a very long time before you need to worry about disposing of them.

Caustic Soda, and sulphuric acid are both used to clear blocked drains so wont cause any problems.


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## BradG (Aug 3, 2011)

Very pleased!

My wife was kind enough to treat me to a selection of anodising dyes for my birthday as you can see by all the buckets. i am particularly keen on trying out the gold one

The other picture is an experiment i am toying with. i found a company which supply Aquatic/homebrew immersion heaters which usually have a temperature range of up to 35C, whereas i need up to 60'C. They are able to adjust the temperature range to cater for what i need so i have ordered one to see how i get on with it in the dye tanks. if it heats it up quick enough and maintains a constant temperature it will be a winner as i will be avoiding using the cooker (keeping the Mrs happy - well, apart from the sealing process any how :biggrin: but at least thats just water)


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## BradG (Aug 9, 2011)

I now have a more detailed version of this tutorial in PDF format. if you would like a copy please drop me a PM with your email address and i will gladly send it over


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## Timebandit (Aug 9, 2011)

BradG said:


> I now have a more detailed version of this tutorial in PDF format. if you would like a copy please drop me a PM with your email address and i will gladly send it over




How about you send it to TomW and he will put it in the Library for all to see?


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## BradG (Aug 9, 2011)

Hi Justin
I have done so and Tom will add it when he has a spare minute.


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## BradG (Aug 9, 2011)

There you go:
Publicly available in the library for all 

http://www.penturners.org/forum/showthread.php?t=77367


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