anodizing two tone

[jct842]

is it posible to anodize a second time for a 2 tone color scheme? I engraved my name on a new flashlight tonight. it is anodized aluminum. I was wondering after engraving through the anodizing it could be placed back in a tank and the bottom of the engraving be colored to contrast. the chemicals used with the electro bath will they remove existing anodizing?

if it can be done a person could creat quite a colorfull work of art! john

 

[prof65]

Hi john

take a look at this page:

http://www.focuser.com/atm/anodize/anodize.html

At the bottom you can see some example of dual-color anodization. Ok, they don't tell you how to make it (you have to buy their manuals or kits) but the pictures can give you some good ideas.

Roberto

 

[nsfr1206]

mini-lathe.com has some info on anodizing.

 

[LongRat]

Yes you can do it.
Caustic soda will remove the existing anodising so you don't want to use any on the pre-anodised part.
After you have engraved through the first stage anodised layer, you need to re-anodise the whole part which will deposit a new anodised layer on the engraving only. The existing anodising shouldn't be touched by the second ano process. The hard part here is getting electrical contact on the part that's already been anodised - you will need to remove an area of anodising in a hidden area to connect up the power.
Once the second anodise layer has been applied, simply immerse the whole part in the dye tank of a different colour and then seal.