Metallurgy help

RVG8tor · #1 07-09-2009, 10:15 PM

I sent my rudder pedals out to be anodized, I also had made rudder pedal extensions out of 2024 T-3. I was not sure what the stock ruder pedals are made of I think 6063. Well anyway the rudder pedals anodized just fine (black) but the extensions would not take to the process. They called me and told me the stuff they were trying, the edges would turn during the etching process but the flat surface would not. I know it was alclad, could this be why it would not anodize? I had scotch brited the heck out of the things and then kit them with a glass bead blast to give them a flat sort of finish. I also bead blasted the rudder pedals and they came out fine. So have a missed something, shouldn't 2024 anodize?

Thanks for any help, this is the "education" part of the building.

G-force · #2 07-09-2009, 10:55 PM

Its the allcald anodizing differently. I just had this happen. Have your polisher (or you) sand the heck out of the allclad pieces to remove it all and reanodize. Or just remake them out of 6061-T6.

RVG8tor · #3 07-09-2009, 11:43 PM

Quote:

Originally Posted by G-force

Its the allcald anodizing differently. I just had this happen. Have your polisher (or you) sand the heck out of the allclad pieces to remove it all and re-anodize. Or just remake them out of 6061-T6.

I figured it was something to do with the allclad. I was surprised the company had not run into this before. The allclad must be fairly thick because I really sanded the things pretty good, I had bent them on a less than smooth bending brake and they had some good scratches in them. I don't plan to redo them and the cost for another batch of anodization is more than I wan to spend, so I will have black pedals and silver extensions. I actually like the look. At least I will know for next time!

rzbill · #4 07-10-2009, 04:13 AM

Interesting.
The local (in PA at the time) anodizer I used did not have any problem with the few alclad parts that were in my batch. There was a finished color difference between the 6061 and alclad parts which I expected. I was somewhat concerned about the 2024 alclad core because it is alloyed with copper which is reported to be bad for anodizing chemistry. (G-forces experience contradicts this) After my success, I had assumed the pure aluminum cladding prevented any significant contact with the copper (edges only).

G-force · #5 07-10-2009, 08:38 AM

The problem lies when the allclad part is polished. The edges and around holes get rounded over more, exposing the base metal. If all the all clad stayed intact, the color would remain consistant. With the missing allclad on the edges, you get two different colors because of the two alloys. It will anodize...just looks splotchy, zebra striped, and two different shades of the color your doing. Its purely cosmetic.

Mike S · #6 07-10-2009, 08:44 AM

I wonder if the fact that one of you is in NC, and the other is in the WA has anything to do with it.

State regulating the chemicals that can be used---??

Kinda like why many Californians go to other states for a paint job, to get away from the water based junk.

Just a random thought.

Radomir · #7 07-10-2009, 08:46 AM

This link talks about needing extra chemicals when doing 2024:

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

the link may be handy for those who'd wanna play with this stuff at home..

CMW · #8 07-10-2009, 03:15 PM

Mike,

Just curious if you told the plating company that the parts were 2024. I've had a lot of 2024 parts anodized (alcad and not) and have not had a problem. I've always informed the plating company of the alloy. It seems that most of the plating shops here in the bay area are very familiar with 6061 and sometimes balk at 2024. The shop I've been dealing with seems to know what the process is for 2024 and the parts come out great. I recently had the t-rail assembly for the canopy anodized. It is a combination of alloys and it still came out fine, but I told the plating company what the different components were made of.

G-Force is right. If the alclad is sanded thru in spots, the anodize will come out splotchy.

I'm also wondering if some of the glass beads didn't embed themselves in the alclad. The alclad layer is pure aluminum. Pure aluminum is very soft and gummy. If the glass from the bead blaster embedded itself it could have prevented even plating.

Chris

RVG8tor · #9 07-10-2009, 03:26 PM

Quote:

Originally Posted by CMW

Mike,

Just curious if you told the plating company that the parts were 2024. I've had a lot of 2024 parts anodized (alcad and not) and have not had a problem. I've always informed the plating company of the alloy. It seems that most of the plating shops here in the bay area are very familiar with 6061 and sometimes balk at 2024. The shop I've been dealing with seems to know what the process is for 2024 and the parts come out great. I recently had the t-rail assembly for the canopy anodized. It is a combination of alloys and it still came out fine, but I told the plating company what the different components were made of.

G-Force is right. If the alclad is sanded thru in spots, the anodize will come out splotchy.

I'm also wondering if some of the glass beads didn't embed themselves in the alclad. The alclad layer is pure aluminum. Pure aluminum is very soft and gummy. If the glass from the bead blaster embedded itself it could have prevented even plating.

Chris

Chris,

I did tell them that it was 2024 and I was not sure of the rudder pedals they actually figured out that they are 6061. I guess it could be the glass beads except I also hit the rudder pedals with the beads and those parts turned out just fine. Maybe the 6061 was hard enough to prevent the beads from embedding into the aluminum.

Cheers

G-force · #10 07-10-2009, 10:28 PM

All the parts I had done did anodize fine, just splotchy due to the different alloys. I don't know what they have to do different, but yes, the alloy is important for them to know to adjust their time and chemicals. I think anytime you have a mix of alloys, your going to have this problem. For the record, theones I had done were red, perhaps different colors are less tolerant to different alloys.