Author Topic: Anodizing parts (Read 18030 times)

mycb750k6 · « **on:** August 05, 2010, 03:45:16 PM »

I have a couple other threads where I referred to anodized parts so I thought I start a thread here for the switch I anodized today and then just build on it.

So here we go - need this switch which has turned gray for some reason back to black.

mycb750k6 · « **Reply #1 on:** August 05, 2010, 03:46:58 PM »

I going to skip the part about polishing it because (1) you know that and (2) I forgot to take a picture.

mycb750k6 · « **Reply #2 on:** August 05, 2010, 03:52:42 PM »

OK here's the setup
The Astron 20 amp power supply - this picture shows it drawing 5 amps for this part. I got this on eBay for 30 bucks. These are used in the ham radio hobby. You need 13.5 volts DC and a minimum of 20 amps so this is the minimum. There are those that say you can use a car battery but I wouldn't know. It's funny, the part will draw the current it needs based on it's surface area, acid temperature, and acid concentration so it's nice to have a volt and amp meter on the power supply. I've seldom used more than five amps of the twenty available.

Other supplies include rubber gloves, goggles, a heat plate for boiling outside, Caswell dye, Caswell sealing solution and some 10ga aluminum wire to attach the parts and cathode , and the 5 gallon bucket full of battery acid solution for the anodizing and the giant aluminum cathode. The acid bucket is in a warm bath to raise it's temperature but also for safety and storage reasons.

This picture show the switch in the acid with the current on drawing 5 amps at 75 degrees for 90 minutes. Lots of bubbles come off the cathode. The switch was attached to a piece of aluminum wire as was the cathode. Everything has to be aluminum or the acid will dissolve it. If bubbles come off the switch, it's dissolving, not anodizing and a connection has been lost somewhere.

The part should be suspended within a few inches of the cathode for uniform layer growth. The bubbles coming from the cathode help to agitate the acid bath but I also use an aquarium bubbler with some plastic tubing to keep the solution agitated and reduce the possibility of splotchy results..

Before the part goes into the acid it must be cleaned with simple green followed by hot soapy water and then rinsed in distilled water. Once you have the setup, it's fine. You just can't touch the shiny part with your greasy fingers.

mycb750k6 · « **Reply #3 on:** August 05, 2010, 03:56:30 PM »

Here's the part after 90 minutes with a gold tinge replacing the highly polished aluminum sheen.
The part gets rinsed in Two separate distilled water baths. You don't want to get any acid in your dye or it will ruin it. The part gets immersed in the dye immediately after rinsing - can't touch it.

The part is attached to the aluminum wire by drilling a hole and tapping both the part and the hole. I've tried many attachment approaches and the connections fail quickly as the anodized layer builds - which is an insulator by the way and kills the anodizing process. This works.

8/6/10 - BTW if the anodizing fails, you can't just start over. The anodized layer to that point must be removed and then you can start over. You do this by dipping the part in a caustic lye solution ( drain opener) for a few minutes. Works well for old anodizing as well. Fives minutes tops or the part will start to pit. Careful as lots of noxious gases are released during this process and lye dissolves flesh so rubber gloves and goggles are required for this and most steps. And by the way, none of this should be done in the house.

mycb750k6 · « **Reply #4 on:** August 05, 2010, 03:57:27 PM »

The dye is Caswell anodizing black
Heat the dye to 130 degrees and let part soak for 15 minutes

mycb750k6 · « **Reply #5 on:** August 05, 2010, 04:01:08 PM »

After 15 minutes plunge the part into boiling Caswell sealing solution and boil for 5 minutes.
This stuff is nasty too so don't breath the fumes.

mycb750k6 · « **Reply #6 on:** August 05, 2010, 04:02:55 PM »

Pull the part out and let cool but it's now ready for reassembly.

I'll fill in some more details but wanted to get started on this.

Ichiban 4 · « **Reply #7 on:** August 05, 2010, 04:16:33 PM »

That's cool Myles!

I always wanted to know the details of anodizing.

Where do you get the dyes and acids? I already have an electro-polisher/anodizer (used to use it to clean/polish dental castings/appliances). So..I figure I'm already half-way to being able to anodize stuff myself.

However..the acids and anodes I have now..are meant to work with cobalt-chrome..not aluminum (glacial acetic acid..stainless steel anodes..et al.). So guess I'd have to change-out those things. Yes..I'm interested in anodizing aluminum BLACK..as you have indicated you're doing.

Looking forward to your reply..as to further suggestions for sources/materials..et al.

Al / Ichi

mycb750k6 · « **Reply #8 on:** August 05, 2010, 04:25:15 PM »

Al,
The dye comes from Caswell as does the sealer. http://www.caswellplating.com/kits/

Actually for other colors you can use Rit dye with success and boiling water to seal BUT NOT BLACK. It's the hardest color to get right. So use the Caswell Aluminum dye and the sealer which comes in powder form. Directions are on the packages.

The acid is just battery acid diluted 50/50. ALWAYS POUR ACID INTO WATER. Never the other way around. Automotive stores carry it. It's cheap. Once you're done you can neutralize it with Lye witch is a strong base.

You just need an aluminum cathode, some 10ga aluminum wire and some battery acid. I got all these from the junk piles at the materials store. If you can tig weld your aluminum wire to the cathode, it will save you checking it for looseness all the time.

Here's a MC I did last week as a spare. You just can't buy this stuff anymore

If you're really interested read this link http://www.focuser.com/atm/anodize/anodize.html . It's how I got started. However this guy's stuff is expensive and you can find most of it yourself for a little over a hundred bucks. You don't have to buy this guy's stuff. It's just a good article, that's all.

Ichiban 4 · « **Reply #9 on:** August 05, 2010, 04:51:49 PM »

Myles..

Thanks for the info..very helpful. Your MC looks great BTW. I sent mine to a so-called anodizing outfit..they said they couldn't get it to come-out..so ended up powder coating it (I was tired of screwing with it after weeks of negotiations..so relented). However..and as you probably know..I have to be careful now with spilling or leaking brake fluid on it..or it starts to lift the powder coat.

So..I may take it off of there..disassemble..and try to anodize it black..like I wanted to all along. Same thing with my brake/slave cylinder..which is only painted black. I can appreciate the guys just polishing up the old-faded anodizing..to bright silver (think the silverish looking faded anodizing makes these bikes look old-used). But seeing a spanking-new black anodized part..just seems to set these bikes off..I feel. And..adds to that touch of nostalgia that we both remember from when these bikes were new.

Al / Ichi

mycb750k6 · « **Reply #10 on:** August 05, 2010, 04:58:39 PM »

Yup, I agree 100%. It's supposed to be anodized - not painted, powder coated or anything like that. And I DO spill brake fluid all over the place. And I really like the way it looks.
As an aside, anodizing hardens the surface somewhat as it grows it layer. I was initially concerned about the bore of the MC. But as it turns out, I just run a 12mm flex hone in there for a few seconds and it's like new

Retro Rocket · « **Reply #11 on:** August 05, 2010, 05:51:59 PM »

Do you think it possible to anodize top and bottom 750 engine cases.?

Mick

scottly · « **Reply #12 on:** August 05, 2010, 08:15:48 PM »

Very good info!! If the donor electrode is a harder grade of aluminum, would that make the anodized layer harder??

mycb750k6 · « **Reply #13 on:** August 06, 2010, 04:00:22 AM »

Rocket, The simple answer is yes. But it would require a much bigger setup than a home anodizing setup. Mainly because the parts are big physically requiring a large tank and acid bath but also because the process requires 12 ASF current flow and with all that surface area you would need a 50 - 80 amp power supply to generate enough current. Heat generation would have to be monitored at that size as well. But the reality is you have to do the math to determine how long to leave it in there at that current draw. Wouldn't want your cases to dissolve

Commercial outfits can easily do it but not the home brew guy.

Scottly, hardness of the anodized layer is determined mainly by the acid bath temperature in the above example. Cooler bath will produce harder surfaces but typically less porous so doesn't dye as well plus takes longer. Remember you can anodize almost any color including leaving it clear just for hardness. The cathode aluminum grade has nothing to do with the hardness but should have at least as much surface area as the part.

Freshly machined T6061 aluminum is the easiest to anodize and almost always gives great results. Old cast 750 parts have varying amounts of impurities in the aluminum casting and give inconsistent and sometimes sub standard results. The key is maintaining the 12 ASF current flow so a power supply with meters is essential plus a very clean, highly polished part to begin with. They say anodizing will bring out the imperfections which is especially true in lighter colors.

HedNut · « **Reply #14 on:** August 06, 2010, 04:49:50 AM »

WOW! Thanks a lot for this info MYCB! This is some Excellent stuff.... I can't wait to try my hand at that!
Cheers! Thanks again!

Bamboozler · « **Reply #15 on:** August 06, 2010, 08:00:00 AM »

Cool write up and thanks for the info! I think I may have to give this a try with my controls and brake parts at well, thanks.

markb · « **Reply #16 on:** August 09, 2010, 06:36:18 AM »

This is probably the most informative, most needed thread for restorations ever.
Thanks,
Mark

mycb750k6 · « **Reply #17 on:** August 09, 2010, 08:37:37 AM »

Thanks mark. Don't know if I'd go that far but thanks anyway. What's I'd really like to see is a write-up and video on how to do bead blasting for frames, cases, heads and so on.

Jerry Rxman Griffin aka MuthaF'er · « **Reply #18 on:** August 09, 2010, 09:54:10 AM »

VERY Good! Thanks. Now we just need someone to provide this as a service to our members.

void909 · « **Reply #19 on:** August 09, 2010, 11:57:40 AM »

Thanks for posting this. Great looking parts

markb · « **Reply #20 on:** August 09, 2010, 03:24:22 PM »

Quote from: Jerry Rxman Griffin on August 09, 2010, 09:54:10 AM

VERY Good! Thanks. Now we just need someone to provide this as a service to our members.

Even better. I'd gladly pay.
Mark

mycb750k6 · « **Reply #21 on:** August 09, 2010, 03:42:23 PM »

Hey mark, sand cast anodized parts would be 900 hundred dollars each.

Isn't that how that works?

How did you get two sand casts and I don't even have one?

markb · « **Reply #22 on:** August 09, 2010, 04:30:30 PM »

Looked real hard and spent too much money!

mycb750k6 · « **Reply #23 on:** August 09, 2010, 05:05:08 PM »

A friend of mine found a sand cast about six months ago, #4646, and promptly registered it on the sand cast only site. I just looked there yesterday and there must be a dozen more registered since then so they are still popping up. Parts are awfully expensive it seems though.

RAFster122s · « **Reply #24 on:** August 09, 2010, 07:45:10 PM »

Anodizing cases would grow anodized layer on the bearing surfaces, not something you will want unless you are willing to machine those to proper size again.
FWIW

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Author Topic: Anodizing parts (Read 18030 times)