aluminum bright dip

[rwtigerfan]

A professional plating company in my area uses what they call "bright dip" on aluminum and it gives a fantastic finish. Even on parts we have deburred by sand blasting. I assume it is some kind of acid but really have no idea. Does anyone know about this? I know the first time they did a sample for me, it only took seconds for this procedure.

[Fibergeek]

This is a mixture of concentrated sulphuric and phosphoric acids, best used at elevated temperature (like almost boiling). Incredibly corrosive and vile stuff. Don't try this, without the proper industrial acid control equipment this is enormously dangerous!

[kickn]

I'm sure I've seen some less aggressive solutions.

I use nitric acid as a degreasing/brightning stage and its not too bad. I did have some recipes for other brightners but can't remember where I put them - Look for a booked called 'Anodising Technologies' and its got a page on it (probably available from your Uni Library).

[vemoo]

So why is the mix do nasty? I'm looking for nasty to restore 50# of old and rusted bolts, bits and pieces. Why is the finish so "desireable" on aluminum?

[acidrain]

Vemoo, Since you've highjacked the thread, I'll point out you are in an anodizing forum. It's important to us for other reasons than to remove rust from old nuts and bolts.
To answer your question though, try some muratic acid. Wear appropriate safety gear, and neutralize the parts (and acid) with baking soda water, then spray with WD-40

[vemoo]

Newbie- My bad, but still could use a description of the finish produced on aluminum. PS: Oxalic is a rust remover and brighter, whereas, IMHE, muriatic just dissolves the part.