What am i doing wrong here?

[rjelliott]

What is going on here? I am still getting a streak in the one piece. The other piece is just dulling. I put both of these pieces in while they were a mirror finish. After i took them out of the ano bath they were dull. I dried them both off and i could wipe off a little of the dull color and i got a chalky film on my hand. Could it be in the water. The water is very clear. I just used soap and water, then the degreaser for about 3 minutes, i skipped the desmut this time and still the same results.

[sswee]

Is the part two pieces pressed together as it appears in the pic?
Any idea of the material grade?
SS

[rjelliott]

Yes they are two pieces pressed together. The one in the first picture is the only one that is streaking. The other one is just cloudy. Not for sure what grade the aluminum in made from. I will see if i can find out. They are Fasst Flex handlebars.

[rjelliott]

I found out they are made from a 7000 series aluminum. Did not say which exact one.

[sswee]

Hard to tell just from pics.
It appears to be a multi-layer problem. The material grade of the two pieces is different. The coating grows at a slightly different rate on the different grades.
The shaft appears to possibly be extruded. The streaking would be the grain of the metal
The end piece looks cast. It looks like it has marbling from the material mix.
The chalky film that comes off on your hand from the one piece is typical dissolution. The reason for that is that material is faster growing than the other.
Are these a no dye job?
Dropping the ano time down will take care of the dissolution or cooling the tank down. The streaking is more difficult to deal with.
SS

[sswee]

Motorcycle parts - cast peg mount brackets had marbling
Motorcycle parts in Fast Blue - Caswell Inc Photo Gallery


motorcycle fork tubes 6xxx and 7xxx pressed together gave different color
Gray NLN - Caswell Inc Photo Gallery
http://forum.caswellplating.com/phot...php/photo/1403

Gold S - Caswell Inc Photo Gallery

[rjelliott]

i wanted to leave the end pieces polished and the bar dyed black. What about the pieces getting cloudy? What is causing that?

[sswee]

The end pieces are the ones getting cloudy? Basically loosing the shine of polishing?
They look cast to me. Most all the parts I've done similar to those, have been dyed which hides much of that. Problem I see is to try and fix that, you would have to reduce ano time, drop tank temp down but dying the center black you need to keep the ano thickness up. Sort of a conflict.

Acidrain is sharp. He may have a suggestion or see something I'm missing.
SS

[rjelliott]

When hanging a part, does it matter how it's hung? The reason I'm asking is when I hung those parts I hung it with a wire from both ends. Would the power entering at both ends of the part have anything to do with what is happening? I did not notice this happening on previous test runs. But it was different aluminum.

[sswee]

I hang parts from the ends like that all the time. No problem there.
SS