A beginners' guide to aluminium anodising?

After some interweb searching, and reading through posts on this website, I would like to attempt home anodising. I've got a selection of tools (and most importantly the patience to fully prepare the parts, degrease etc etc)

Yes I realise there are a number of anodising companies out there, but where would be the education in paying a pro to do it?!

I'm hoping others who have had successes can share their step-by-step guide for colour dying aluminium - I don't imagine it's too reliant an the exact aluminium alloy?

Any help gratefully received.

You need to be aware that if you wish to use the same colour on a number of parts that will be used together, if they are made from different alloys they will not be exactly the same colour.

Forgot to ask, can someone recommend a dye supplier?

Dig out Ramon's articles that were in MEW for a good simple guide. You don't need the special dyes, fountain pen ink works quite well as you can see.

Edited By JasonB on 18/07/2018 18:41:34

Never tried it myself (yet) but I'm told Dylon fabric dies work well; the ones in the little round aluminium tins.

Bill

This subject has been covered a few times on this forum, I have put a link to some previous threads on here which maybe useful to you.

**LINK**

Hope this helps.

Edited By V8Eng on 18/07/2018 22:14:09

How do I order a back copy of MEW? I clicked on the "Back issues" on the header ribbon on this site, but October 2012 MEW isn't listed in the online store?

I'm guessing it's not possible to buy just that article, since I clearly don't need the remaining 80% of that issue?

I thought it was covered in one of the modelling books by argus. Sorry i can not find a link

bri

I seem to recall that someone did a trial using Dylon fabric dyes and concluded that the results were very mixed. If I remember correctly there was a red shade that worked well but some other colours were not worth using. I think small quantities of proper anodising dye can be found on ebay at reasonable cost and this would probably be a good idea for a novice, to increase the chance of success.

Doug

EBay list several anodising kits, depends on how much you want to do. The basic kit will do what you want. One comes with a 10 Amp power supply.

I have tried this, using this article as a guide: **LINK** and got good results, with or without the dye.

I bought the black dye as crystals from ebay, a Chinese constant current power supply, also from ebay, used roofing lead as the cathode and aluminium MIG welding wire to hold the components being anodised. I modelled the components in CAD to calculate the surface area and hence the required anodising current.

One thing that surprised me was how effective the anodised layer is at not conducting electricity - touching the surface with the ohm meter probes shows infinite resistance. But dunk the item in caustic soda for a few seconds and the anodising is gone and conductivity returns.

Apart from all the stuff you need to do it (tank, power supply, battery acid, dye, lead cathodes, work holders etc) what I found a faff was the time required for each stage - anodising, dying, sealing. That's about three hours to do one small component. I'd consider making the part out of black Delrin if you can and save all the trouble.

You may want to check first that you can get hold of sulfuric acid of the required (quite high) concentration. The explosives precursors and poisons regulations now say that "From 1 July 2018, members of the public who want to acquire or import sulfuric acid above 15% weight by weight will require an explosives precursors and poisons (EPP) licence”. I've no idea how effective those regulations will be, but they may well make life a lot more difficult. Certainly EPP licenses are not handed out easily. You can still buy anodising kits on ebay.

Dare say these sellers are not operating by the current law (breaking it) and selling what otherwise would be redundant stock.

Getting a explosive licence near on impossible for non business, the paper work, checks etc you just dont want to know even 16 years ago.

Tried every dye i could get hold of 15 years ago from Quink to fabric dyes, no luck. Ended up finding a supplier to anodisers over Leicester and had the same powder sent.
This was at the time 4 articles worldwide on anodising, all told porkies by either omitting key areas to blatant lies. There is a lot more write ups these last 10 years with kits available.

Different aluminum grades will yield different colours.

Depends what you want to do theres three types of anodising.
Chromic is just cosmetic wont last at all if touched and wafer thin.
Sulphuric the most common, lasts and a far better depth to the colour.
Hard anodising is sulphuric Type 3 thicker penetration and extarnal gain. Colours will look rather different and i have only ever achieved this twice.

Have seen a number of results from 6 people using those home brew kits, so far i have not seen a presentable item. In fact got one here but a picture wouldnt do it justice as it wont pick out the blemishes, blue tint and almost black patches. This is with simple items turned and spin polished, if used bead blast would look hell of a lot different like coarse matt.
I use 60/120 grit for bead blasting items but specify to a professional i want it satin to a sheen and know what theyre doing being the only one to date found. Others 'Will' scrap the part 9 out of every 10 items guaranteed.

Go ahead with anodising, it's not too difficult!

I remembered that (quite some time back) I put a picture from my first trial in my album. A small test piece, coloured with magenta Inkjet ink. I added now another two, showing parts from my tonearms. The blue parts are also done with inkjet ink, blue this time

The parts on the other arm are coloured with products from The German firm 'Electronic Thinks'
Black and Titanium colour, which is more like dark Bronze.

**LINK**

Here you can get all what you needs for your anodising projects.

Btw. I made some tests with those textile colours, but no success. It seems that only one of the different Dylon (?) products can be used, and it seems this one is difficult (or impossible) to find.

OK, here then the pictures:
Sorry for the dust, i did my best to clean all before taking the pics, but with flash one sees the smallest speckle...

Otley says:

One thing that surprised me was how effective the anodised layer is at not conducting electricity - touching the surface with the ohm meter probes shows infinite resistance.

Well spotted! This is the effect which makes electrolytic capacitors work. Instead of a paper or mica sheet between the two sheets of electrode, they use pure aluminium for both cathode and anode, and anodise one side. The canister is filled with a liquid similar to anodising solution, and the charging process actually keeps the insulating anodised layer in good condition.

If you connect such a capacitor the wrong way round, or on AC, the insulating effect fails, a large current can flow, there is usually a bang, and some of the innards are deposited around the device, looking exactly like seagull shit.

Enjoy your tea ...

Cheers, Tim

Try Gateros Plating, very helpful.