Aluminium

These people do kits for all sorts of metal finishes. Their cat. gives quite comprehensive details - but you'll have the to check the website yourself to see if it does too as I'm off to watch TV.

I think caustic soda would just dissolve the aluminium.

It's not anodising, is it?

Anodising increases the thickness of the surface oxide layer, which is absorbent and can be dyed to pretty colours. That's also why they can't get all the paint off underground trains when they've been defaced by morons with spray cans.

Idiots' anodising guide here;

If it's not anodising, then just ignore that.

Thanks for that,but no it didn't disslove it as it was not in the caustic solution long enough for this to happen bearing in mind also its strenght.

I have done this ,but as i said it was quite some years ago.

The process gave the aluminium surface an semi matt appearence something like brushed aluminium.

I was looking at this site,similiar to what you posted.

The message from "Aidan" contains these words:

It does if you leave it in too long, but I've done it - oddly, from a suggestion in a very old electronics mag, and a pint of warm water with a tablespoon full of caustic soda in it does produce a passable finish.

Anodising it is not - nor is it a patch on proper anodising, but it's OK for some uses.

Hi there FWIW I remember this too - as distinct from anodising, which I also know and have a had a go at. I was a schoolkid when I tried - about all I can remember is:

- it must have been pretty string as I'm fairly sure it was a satisfyingly 'bubbly' mixture, and yes I do know to add soda to water

- I think I first prepared the Al by scrubbing it with steel wool. IIRC this was part of the process; the action of the Caustic solution on the 'grain' of the metal created this way was part of the point.

- I think the panels went in for only a short time, say < 30secs.

Sorry I can't dredge up more. Have you tried somewhere like the repairfaq?

jon N

but where can I obtain Sulphuric Acid?

I didn't think The Bill was on tonight :-)

Owain

The message from "The3rd Earl Of Derby" contains these words:

Old batteries.

Watch that rubbish? ;-)

Naw - it was Judge John Deed I wanted to see. ;-)

Ah, my telly guide had World Cup, so I haven't put my telly on today.

Owain

Caustic soda etches aluminium, removing the protective oxide film. It has to be handled carefully in this state because it stains so easily. However a thin oxide film does grow back fairly quickly. Professional anodising grows a thicker film by electrolysis.

Radiospares used to do an aluminium labelling system (was it Copyphot?) where the final stage was to immerse the label in a hot solution of some magic salts that chemically grew the protective oxide film.

Such as?

Not challenging, just interested!

Mary

The message from "Mary Fisher" contains these words:

I used it for a bit of alloy that covered a hole where something else had previously been - just to stop it taking up fingermarks so badly. It wasn't a frequently used bit.

Oh ... thanks

Mary

I've got an RS aluminium 'printing' system, but it starts out with specially coated anodised ally. You expose the coated sheet to UV via a mask and then dye the parts needed in a variety of colours.