Restoring faded color to anodized aluminum

[JosephS]

So while polishing up one of my chassis I managed to over polish a have grey spots on a black chassis.
The anodize is still present so I don't think aluminum black would work. Has anyone come up with a way to darken faded dye.

I was thinking of trying to dye the chassis, but I have *not* seen evidence that it will help.

[radioactivity]

Hi Joseph

I agree, I don't think Birchwood Casey aluminum black would work very well.
I have tried it on freshly cut and sanded/polished aluminum and it doesn't really doesn't work that well. Maybe on a small scratch it would be Ok.

Aluminum type dyes rely on the pores opened by anodizing to color the aluminum.
I can tell you that excess organic dye on a newly anodized/dyed/sealed part can be easily removed and is chalky in appearance. It is on top of the sealed aluminum and it doesn't penetrate the aluminum.
Maybe powder coating would be a solution, then any color would be possible.
Sorry, no quick fixes I know of...

A possible source of info is https://forum.caswellplating.com/.
I have spent a lot of time there trying to learn more about anodizing and anodizing failures.

Chuck

[JosephS]

Hi Joseph

I agree, I don't think Birchwood Casey aluminum black would work very well.
I have tried it on freshly cut and sanded/polished aluminum and it doesn't really doesn't work that well. Maybe on a small scratch it would be Ok.

Aluminum type dyes rely on the pores opened by anodizing to color the aluminum.
I can tell you that excess organic dye on a newly anodized/dyed/sealed part can be easily removed and is chalky in appearance. It is on top of the sealed aluminum and it doesn't penetrate the aluminum.
Maybe powder coating would be a solution, then any color would be possible.
Sorry, no quick fixes I know of...

A possible source of info is https://forum.caswellplating.com/.
I have spent a lot of time there trying to learn more about anodizing a anodizing failures.

Chuck

Thanks for the information. I didn't think there was much but if any group would know it'd be this one. Looks like I need to find a nice sticker and move on.

[Lowgear]

Off topic but a year or two ago after having a bunch of steel R/C parts that needed refinishing, I started researching what could be done at home by simple means.

I ultimately decided that gun bluing fit the bill for most of the parts I had. I bought what was necessary, and gave it a go. I was absolutely thrilled with the outcome! I'm so glad I learned how to do it. All the parts I did were for shelf queens, so I don't know how the finish would hold up if the parts were used. I'm thinking if it's good enough for firearms, it should do pretty well. Either way, they came out looking amazing, and it protects the bare metal.

I'd like to try electroplating next as it seems pretty easy to do on a small scale. I found some good videos on YouTube showing just how cheap it could be done for. I looked into the Caswell products during my research but they want way more than I'm willing to spend, as they're expecting you to be doing much larger parts.

[marlo]

I remember a thread from awhile back, maybe 8 years ago, I can't find it. The auther used rit dye in boiling water, then baked it in his kitchen oven. The finish looked factory from the pic's. I remember wondering how durable the finish would be though!

[JosephS]

I remember a thread from awhile back, maybe 8 years ago, I can't find it. The auther used rit dye in boiling water, then baked it in his kitchen oven. The finish looked factory from the pic's. I remember wondering how durable the finish would be though!

Thanks. I’ll give that a go.

I was thinking of something like that, except I was going to use a torch to smoke the spot. Given the anodizing is underneath the most you would loose is the ‘finish’ that can always be redone.

You wouldn’t happen to remember me the oven temp being high or low would you?

[JosephS]

Off topic but a year or two ago after having a bunch of steel R/C parts that needed refinishing, I started researching what could be done at home by simple means.

I ultimately decided that gun bluing fit the bill for most of the parts I had. I bought what was necessary, and gave it a go. I was absolutely thrilled with the outcome! I'm so glad I learned how to do it. All the parts I did were for shelf queens, so I don't know how the finish would hold up if the parts were used. I'm thinking if it's good enough for firearms, it should do pretty well. Either way, they came out looking amazing, and it protects the bare metal.

I'd like to try electroplating next as it seems pretty easy to do on a small scale. I found some good videos on YouTube showing just how cheap it could be done for. I looked into the Caswell products during my research but they want way more than I'm willing to spend, as they're expecting you to be doing much larger parts.

Bluing looks awesome as a process. It fades with wear but parts getting constant friction don’t rust and that’s the point. When I looked into it it seemed bluing cost about the same as plating when you get all the tanks and chemicals set up.

Creakote looks awesome to me. It seems like it should of be very similar to powder coat, but a bit stronger.

[Frankentruck]

If you oven bake the chassis, watch the temperature. Once aluminum gets close to 400F it starts to soften.

[jwscab]

Correct, you start to lose the temper of the alloy above 450F. Also why I don't recommend people weld holes shut. powder coat can also get close to weakening the chassis.

[Dadio]

The trick with aluminium is to cool it very slowly in order to keep its temper .

[radioactivity]

I'd like to try electroplating next as it seems pretty easy to do on a small scale.

It can be very rewarding. Really not all that difficult.

Prep and absolutely clean/polished aluminum is a necessary starting point.
An excellent connection between the part and the hanging wire is very important. I've had several failures there.
I've only been using small plastic containers for the acid bath and an old crock pot for sealing. I too felt Caswell kits were both pricey and geared towards larger projects.

My first attempts with a battery charger, battery acid, aluminum cathodes, Rit dye and sealing in boiling water were at about 1 success to 3 failures.
Only real luck then was with blue Rit dye, black Rit dye has never worked for me.
More careful monitoring of time and temperatures using Caswell's 720 formula yielded better results. Then it was about 50/50.

Now using a constant current power supply (30V 5a), Caswell dye, sealing with nickel acetate and even closer attention to time and temperature I get 6 successes to 1 failure.
Recently been having smut after sealing but it polishes up very nicely. Still haven't figured that out yet...

6061t6 is the way to start, blue is the way to start in my opinion.
Anodizing the Duralumin ( high copper content) on the TOMSE has been agonizing with the amount of failures.

Would be interesting to see others techniques and successes/failures.

Chuck

[JosephS]

If you oven bake the chassis, watch the temperature. Once aluminum gets close to 400F it starts to soften.

Since I have no guide, I'll start at 350 since I can at least make ribs at the same time. I may wind up disappointed, but I'll be full.

[JosephS]

It looks like Caswell may have a kit that would help.

https://caswellplating.com/anodize-touch-up-kit.html

I am not sure if this is just a degreaser, aluminum black and, a sealer.