Wanted - Simple-> Anluminum Anodizing Methodology

[SpiralGroove]

Hey Guys,
I'm looking for someone who has perfected the simple art of anodizing aluminum.
A very cheap and simple process - If there is one?   Not looking for anything fancy - only good, simple results in black, silver or brass colors.

I like to tinker if that helps..............

Kirk

[shorty]

Where I work we anodize aluminum ribbon wire continuously "reel to reel". Been doing it for over 20 years. We do an unsealed mil spec of only a couple microns thick to make a dielectric barrier.

I have toyed in the lab with some organic pigments. Just messing around I anodized some small aluminum bobbins and then pigmented them hot pink ( boring day at work and was just having fun ).

Anyway, I do have to add caution. 10% to 15% H2S04 is seriously dangerous and can be difficult to dispose of. Not only that, you will need plenty of PPE.Glasses,gloves, goggles ect. Absolutely no open flames as H2 is generated during the anodizing process.

Just mixing the acid wrong could be a disaster. Remember, Acid to water always. never water to acid.

Its an easy process but could be extremely dangerous.

Please be careful.

[Airsnipe]

I have been anodizing my own parts with a pretty simple setup for over a year. I would not say I have "perfected" it or an an expert by any means and I am still learning but I do get pretty good results IMO. I would like to here from others with more experience myself.

I got my info from youtube and reading around on the web. There is quite a bit of info out there, and it can be a lot to sift through. I will not give you an all telling guide (that would take to long) but here are some tips. Even a "simple" setup will cost you some $$ unless you just happen to have a lot of this stuff just laying around.

 I have got supplies from Caswell and Bright Dyes as well as some items you can generally get locally. The main things you will need to get from places like this will be the dye/pigment and a sealer. There are other things you can get like de-smut products among others but you will at least need proper pigments and a sealer. You can seal in boiling water but I have always used a sealer.

You need a power supply. This will be dependent on the size and quantity of parts you want to do. More surface area requires more power. I recommend if you are just doing a few small part, to just buy a cheap lab power supply off ebay. 5-10 amp units don't cost that much and give you the ability to adjust amperage, unlike a battery charge. Although I have seen people get decent results with a battery charger, I personally have never used one. I use this calculator to determine amps needed based off of the parts surface area. http://ndhsubmersiblescience.com/ano/720rule.html

My biggest challenge at first was getting the parts clean enough. You have to make sure the parts will sheet water and not bead water. If water beads up on your parts, there are oils still on the part that will cause problems. I found that Comet works pretty well for cleaning parts as it has chlorine in it which will actually break down the oils (to my understanding) and seems to give you good results pretty quick and is readily available and inexpensive.

I use a 10% sulfuric acid for the anodizing bath. Acid can be found at an auto parts store and is generally 30% I believe. This stuff can be dangerous so do some research on using acids if you don't know the ins an outs. Like already stated, always add acid to water and not the other way around. Agitation is a good thing in the anodizing bath. I see many people using a fish tank bubbler for this but I found that will cause un-needed acid spray all over the surrounding area so I prefer a magnetic stirrer. Duda Diesel has a reasonably priced magnetic stirrer. But they are also pretty easy to make.

The negative connection in the tank (parts are positive) can be either lead, titanium or aluminum. If aluminum, it will need to be removed and rinsed after each use. Lead seems to be pretty commonly used. 

You will need some titanium wire to hang parts from (another challenge that can be hard to explain). You can use aluminum wire but you will need to replace it each use so not really cost effective. You need a good electrical connection to your parts. It seems the grade of titanium doesn't matter but grade 5 is easy to find and is springy which can be useful. Grade 2 is a lot like 6061 aluminum as far as its lack of spring. Grade 2 is really easy to bend but has very little spring. Grade 5 is harder to bend but is very springy. Stainless wire will not work and will contaminate your bath. Another thing to note here is that all electrical connections need to be secure. A poor connection outside the tank can result in sparks and hydrogen gas is produced during anodizing so any sparks can be dangerous.

The pigment bath and sealer need to be heated so electric hot plates are handy. They are usually pretty easy to find at thrift stores for cheap. I use all HDPE containers so I use a pot to "double boil" the baths. Nothing I use actually gets to boiling temps though. Also a coupe thermometers as keeping an eye on temps will help with get consistent results. Note: anodizing bath is not heated.

Using distilled water is the best option for all water used in the precess. A good spray bottle is handy as well to spray off parts during the process. I prefer a spray bottle apposed to a clean water bath simply due to the small parts I do and many have small holes, it can just be easier to get parts rinsed well with a spray bottle. And it's also less wasteful since you can replenish some evaporated water by rinsing the part off into the bath it's coming from, if that makes sense.

Well thats all I can think of off the top of my head. Hopefully it's helpful. Just do some research and use common sense and be safe.     

[Pete]

There a post of mine in the OLD GTA on my set up i
used for muzzel brakes etc...

Go find if yer half interested..   

http://www.gatewaytoairguns.com/airguns/


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