Home Anodising Aluminium and the elusive Sulphuric acid

[wal2789s]

Was browsing the net on how to do this and came across this site for the Acid...
Battery Acid : UK Chemical Suppliers, Buy Chemicals Online

And here's the procedure....
http://astro.neutral.org/anodise.shtml


Just thought someone would like their CNC made with Aluminium in a had scatch free surrface with any colour they fancy.

I had the same issue, I ended up using Anodising First Choice Anodising First Choice - Hard Anodising, Soft Anodising, Colour Anodising, Chromic Anodising, Powdercoating, Electropolishing to remove my anodising as like other said, its hard to get hold of strong caustic based acids to remove anodising, especially hard anodising. They only charged me £10 and gave it a light polish over for free too!

[Jonny]

That links extortionate pricewise i paid £32 for
10lts Hydrochloric acid 33%
25ltr drum of distilled water
25lrs Sulphuric acid 33%
Unfortunately the place where got it from dont want me to broadcast.

Until last 8 years or so there was only three internet sites providing info how to, none worked.
For me sulphuric at 19% running 14.2v. The only success was if wedged in aluminium in to a hole really tight.

[Chas]

I've been home anodising using the 720 LCD method for years with good & repeatable results. If you follow the rules it's easy.

Caswell have an excellent forum that caters to beginner's & experienced alike.

Anodizing Questions

You don't need to spend £100's on equipment but I'd STRONGLY recommend an investment in a constant current power supply if you don't want every run to be an experiment.

I get my acid & water from a local truck & forklift battery supplier in 25l drums, every town should have one nearby, ask at your local forklift hire & sales Co'. Caustic soda should be readily available from any 'proper' DIY hardware shop, I get mine from Wilko's at £2ish for 500g.

Most of my failed runs in the early days were down to using alu' wire for the part or allowing the temp in the tank to rise too much. Now I use titanium welding rods & a bilge pump to circulate the acid.

[Jonny]

Started off with one of these, didnt last long GW Instek GPS-4303, 200W Quadruple Output DC Power Supply, 0-30V, 0-3A from Conrad Electronic UK
In a panic needed something quick next day Triple Output Power Supply : Bench Power Supplies : Maplin Electronics Gone down in price £21.

Caswell wasnt doing the kits then. Have done hard anodising three times by accident, dont ask how not a clue essentially same method i used to use for normal sulphuric.
Too true, drove me round the bend loosing electrical contact. Waste of time using aluminum wire, used to use wedges rammed in to a hole dead tight. 50/50 whether lost electrical contact. Used titanium a few times later on with a wall of lead lining one rear face of a fish tank. Larger 4ft tank lined with aluminium foil on bottom and rear face.

Always had trouble with the colouring and eventually figured its got to be warm but well short of boiling. The part will seal around 90+ degrees or become brown/purple/blue. Tried everything i could get my hands on for a dye, no substitute for the real thing.

Does the sulphuric go off, the little tanks been outside for at least 5 years?
4ft fish tank broke gallons.