Making aluminum different colors

Keith Tanner said:

tuna55 said:

So what did you do?

I went on vacation. 

BEST. ANSWER. EVARR.

Keith Tanner said:

tuna55 said:

So what did you do?

I went on vacation. 

Was the aluminum purple when you got back?

tuna55 said:

Keith Tanner said:

tuna55 said:

So what did you do?

I went on vacation. 

Was the aluminum purple when you got back?

I guess we’ll find out. But I would be surprised. 

Somewhere on GRM, I believe Doc Brown, anodized some stuff using RIT dye. It was in his hyper-miler Festiva powered Miata thread. Seems like he just used a battery charger, or something like that. Mix blue and red RIT dye? 

Might be worth looking at Dupli-Color’s Metalcast line of color coats as an alternative to actual anodizing. Linky

wheelsmithy said:

Somewhere on GRM, I believe Doc Brown, anodized some stuff using RIT dye. It was in his hyper-miler Festiva powered Miata thread. Seems like he just used a battery charger, or something like that. Mix blue and red RIT dye? 

I was able to successfully anodize some aluminum parts for the Miata project.  Unfortunately Photobucket killed that build thread.  Anyway you can get a plug-in for your internet browser that restores the links and check out these Blue anodized parts...  about halfway down the page.

Rite fabric dye worked great and the anodizing still looks fantastic after two years.  The DIY method only requires a few steps for an acceptable finish, but isn't as durable as a pro finish.   

I decided to give it a shot. I needed a power supply anyhow  I ordered some dye from Caswell, picked up some battery acid and read everything I could.

And check out this success! That's the aluminum wire that was supporting my part in the various baths. The edge of the color change is where it stuck out of the anodizing bath, not from the dye bath. Woo!

But, umm, the part I want trying to anodize was not made of wire.

Yes, that part is cast. And now that I know to check specifically about anodizing cast aluminum, I know that this is basically what to expect. It's usually alloyed with too many other things to work well.

Poop. 

On the plus side, I've proven I can do it. I have some gorgeous wire and the tools to do it again. But it looks like I'll have to go to powdercoat or paint for this particular project.

I will admit that this is kind of a cool finish even if it isn't intentional.   

So... what kind of pedal is going in the enclosure? Looks like one of the nicer hammond style boxes.

A BYOC Octave Fuzz, aka the Purple Haze effect. Thus the color. 

Cast is very difficult to get even shades across the surface as the molecules of silica (I recall but brain is fuzzy) move around as it cools leading to uneven etching of the pores.  That why you rarely see motorcycle cases anodized in any thing but clear.  I've tried it it can be done but takes time i had better luck with lower power longer time etch.

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The back piece (the flat bit in the first photo) was done at low power, low amperage. Like, really low. I think it was pulling about 1A at 12v. That one announced it was done when the aluminum support wire gave way, basically eroded through.

For the second one, I figured out how to run my power supply with a set current level. It went at 5A, starting at 18v. After about 15 minutes, the voltage started to drop. In other words, it was pulling more amperage. I'm thinking it started to build up a good layer of oxide and the resistance started going up - or do I have that backwards? I get mixed up on electrical stuff.

Regardless, the finish is almost identical between the two. The first piece is slightly glossier and a little bit lighter, but I also didn't leave it in the dye quite as long and you really need to put them side by side to see any difference. They both feel different than they did before the tank - very, very smooth and low friction. This is after the last boiling step that made it all smooth. The previous shots were just out of the dye. The two-color wires went all glossy when they got boiled.

For this particular project, I think I'm going to do some graphics in vinyl and then either leave it alone or clearcoat it. Maybe leave it alone so I can see how it wears, this might get some interesting patina.

In reply to Keith Tanner :

Relic'd guitar pedals could be the next big thing, I could see it.

I crossed the streams! I wondered, what would happen if I took an electro-etched part and anodized it?

Voila! This is just a scrap piece I had sitting around, and it was fairly well oxidized. I didn’t want to sand it clean because I’d scuff up the dark bits, so it didn’t anodize very well as expected.  Had I done the two procedures back to back instead of letting it sit for months, it would have worked much better. I also didn’t work very hard on getting a solid electrical connection.

But as a proof of concept, it’s perfect. The dark etched bits are (I think) full of aluminum oxide and are effectively masked. This opens up some interesting possibilities.