Best way of removing anodising?
 

I am currently working on a 23mm Corsa big axle conversion for my SP5 and want to strip the anodising before re anodising.What is the best way to strip it without damaging the aluminium?

Doing it by hand is going to be a ball ache!!

As with all anodising its etched into the surface of the aluminium so you can't avoid some form of damage

The company that anodised will\should be able to strip it chemically then you have it back and work on the flaws if any. Then give it back to them, must be devoid of all steel thou.

Drain cleaner!

Technically it's Sodium Hydroxide (NaOH) but is sold as "Caustic Soda" drain cleaner - just check the contents to get a "cheap" one which is 100% NaOH rather than got lots of nice smelling soap and other additives in it.

Mix around 1 egg cup of caustic soda into each pint of warm water (REMEMBER: always chemicals into water, not the other way round!) in a plastic bucket and the you simply put some wire onto your part and drop it into the bucket. Leave for about 5 mins or until you're happy with the finish, then take out and rinse with plenty of cold water.

You may get some black residue left behind, but this is just the result of the chemical reaction. You should easily be able to rinse this away.

To dispose of the caustic soda you can just flush it down the drain - it's drain cleaner! Best to put a bucket or two of water down the drain after as well to clean it.

Beware that it is actually eating away the aluminium, so don't leave parts in there overnight. It also dulls the surface so you may need to repolish after. Also remember that because you've removed the anodising (the hard outer coating) it will be much softer now so will scratch easily.

Our local Asda sells it for about £2 for 500g (which is actually quite expensive) but it's easy to get and you don't use much. This is the one:

I'm 59 now, but when I started work at 16 I had a Triumph Bonneville. Anyway one week the engine blew, I took the head into work and this guy said put it in that solution it will clean it properly. This was a Fri afternoon, Monday morning, all excited about my shiney head, :D I pulled out the steel exhaust/inlet stub everything had just dissolved. :o

At the age of 16 we were using it for cleaning 2-Stroke Exhausts

Thanks mate.Now,to find something big enough to take a swingarm!

I'd be very careful going down the caustic route on a DIY route. IMO, have a word with whoever is going to reanodise it for you and have them do it.
The anodising on the arm is more cosmetic than an engineering finish and won't be very thick. It'll probably polish off. It'll need polishing before refinishing so you'll be half way there.....
Alloy can dissolve at an alarming rate unless you're careful and know exactly what strength you need and/or are dealing with.

Thanks Nelly.

I have been looking at a method for doing small parts on my bike. In the end I attacked my side stand with some emery cloth and I was surprised how easy it was to get through to the alloy to be able to polish it.