DIY Home Aluminum Anodizing


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  • Improving my DIY anodizing

    What to see the the start of the home aluminium anodising guide?

    Excited by my result I decided to try and improve things I bit. For some reason I had some nagging doubts about using a PC power supply, so the first thing I did was raid the parts bin and make a simple 12v power supply from a 120VA transformer and a bridge rectifier. Make sure your wires are rated for at least 5 amps, preferably 10 amps. Putting an ammeter in the circuit lets you see whats going on.

    The next thing I did was get a slightly bigger tank, and mix up the full 2.5 litres of acid solution. I made a bigger cathode from the lead, and rigged up some aluminium U section to hang things in the acid with, and got some aluminium wire.

    I purchased various substances to try as dye. The most successful dyes are Dylon clothes dyes. The key is to have an organic dye that is small enough to enter the microscopic pores in the unsealed anodized layer. I tried some writing inks, but that was less successful. Food colouring works very poorly, and then only if it is organic. You can buy commercial anodizing dyes, but for now I will stick to the clothes dye as this works well enough for me. I suspect the clothes dye could fade a bit in sunlight over time.

    I also purchased some Caustic Soda granules. This must be mixed up into solution and your aluminium part can be dipped in it - this etches the surface and removes grease and gunk... it also removes the natural layer of rough anodizing ready for the acid tank.

    Dipping aluminium into a strong caustic soda solution is fun. It fizzes in a terribly satisfactory manner and gives off a lot of smell vapours. And I mean a lot. Its a bit like a gas attack on the Somme. Don't do it indoors. Do it outside. At the top of a mountain. In a stiff breeze. It also splatters hot caustic soda solution over anything it can reach. Don't have anything you might want to keep nearby. Don't forget the main domestic use of this stuff is dissolving and unblocking organic matter out of drains. Your hands are organic matter. So if your wife's favorite wooden chopping board. You have been warned.

    Shops like B+Q can be searched for most of the things you need.

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