Gun store Shooting Locations It is currently Thu Mar 28, 2024 1:21 pm



Rules WGO Chat Room Gear Rent Me Shield NRA SAF CCKRBA
Calendar




Reply to topic  [ 4 posts ] 
 How to anodize all your aluminum parts 
Author Message
Site Supporter
User avatar
Site Supporter

Location: renton, wa
Joined: Thu Mar 17, 2011
Posts: 4062
Real Name: below me
How To Anodize All Your Aluminum Parts

Adapted from an article on Paintball Times
http://paintballtimes.com
Originally Written by Jay Mac

Supplies Needed:
The first thing to do is to get the following things together: First on the list is the most expensive item: a 6 to 12 volt battery charger. They run from $45.00 to $110.00 depending on model, functions, etc.(The next item, though not that expensive, will take some effort to find: battery electrolyte, a.k.a. sulfuric acid. This should be available at a battery wholesaler for about $2.00/gal. To make the negative ground, you will need some aluminum ground wire and aluminum-foil. The wire can be found at an electronics store for about $35/spool, and you should have the foil in the kitchen. If you happen to be out of foil, you can pick up some more at the store when you go to buy the last item for this project. No super-special chemicals or solutions necessary to make the colors; just plain-old fabric dye. (Something like Rit dye, for about $5.00.) Rit offers something like 30-40 different colors, so you have quite a number of choices for what color you want your parts to be. An optional item is nitric acid: about $25.00/2.5 L. (This is used to clean parts prior to anodizing, but there are some cheaper alternatives. See end notes.) This is available at chemical supply stores. Should you not be able to find any, you can try to get on the good side of the high school science teacher. He may help you out since you only need a few ounces.

Safety Precautions:
There are a few precautions I want to go over to help keep you from blowing up the house or trashing the garage. First of all, do not mix or store your anodizing solution in a glass container. Something could happen to make it break, and most households are not equipped to deal with that kind of spill. You also don't want to knock over the container, so a stable, rubber bucket makes a good choice. You will also need to be certain that the part you want to color will fit in the container without sticking out of the solution, and without touching the negative ground in the bottom of the container. Any acid that you don't use, keep in what it came in, or an old plastic bottle, like a bleach bottle. You can also store your used solution this way for doing more parts later. (Make sure that there is absolutely no bleach left in the bottle. Acid and bleach make chlorine gas. Very bad. Don't breath. Poisonous.) Safety also applies to the nitric acid, but in a different way. It is imperative that you label and keep track of this stuff, as it is a stronger acid than sulfuric, and more dangerous. The breakage/spill problem is not as likely since you won't have that much around. (Unless you bought more than a few ounces from the chem store.) The last note about the acids is to mix properly when adding acid and water. Always pour acid into water, never the other way, and do so slowly, being sure to mix in well. There is a reaction taking place and it releases a lot of energy. During the anodizing process, you will be running electricity through a weak acid solution. This creates hydrogen (just like charging a battery) which is very flammable. This stuff burns at the speed of thought when ignited, so do be careful. (Read as Remember the Hindenburg?) Make certain that there is some way to ventilate the project area, and DO NOT let any sources of ignition (NO SMOKING) near the project area. Other precautions you should take include safety glasses, rubber gloves, and maybe some sort of drop sheet under the area.

Preparations:
One of the most essential things you need to do in order to get even color over the whole part is to be sure that the part is absolutely clean. You want it free of all contaminates, from dirt to the oils in your skin. This is where the nitric acid and some rubber gloves will help. A solution of 1-2 ounces of nitric acid in a gallon of distilled water will allow you to clean the surface in preparation for the anodizing. Aluminum oxidizes very quickly when exposed to air, so the easiest way to keep it clean is to clean it just before you are ready to start working on the piece. (You should rinse the part with distilled water before you put it in the next acid solution.) Other options are carburetor or brakes cleaners, or other similar degreasers. Soap and water will work also, or cleaners like Simple Green. These are cheaper, a nitric acid wash is the best. (You decide, it's your money.) =) Make your negative ground with the aluminum wire and foil. Shape the end of the wire into a paddle shape and cover the round part with the foil. What you want to do is create a flat, round shape to sit on the bottom of the bucket, with a lead that comes up out of the bucket. You will clip the battery charger's negative lead to the wire that comes out of the bucket. When you are ready to start, you will want to mix up your immersion solution. In your rubber bucket, combine the sulfuric acid and water to come up with a solution that is about 30% water. (1 part water to 2 parts acid.) Place the paddle in the bucket and attach the negative lead. Then attach the positive lead to the part, making it an anode, and immerse it in the solution. (Remember that thetwo leads the paddle (cathode), and the part (anode) should not touch.) This is the best time to turn on the charger: once the part begins to fizz, leave it in there for about 10-15 minutes. After about this time the part should no longer conduct electricity. (You can also use an ohmmeter to check conductivity, but this is not needed.) Turn off and disconnect everything, and rinse the part in cold water. Don't use hot water! You'll find out why in the next section.

A couple of notes:
I have read some other procedures that say it is important that the copper lead from the charger does not enter the acid solution. The article says nothing about this, and shows a picture with the lead right in there. It may take some trial and error to find out if this is a problem. It wouldn't be a bad idea to get some scrap aluminum and play with it before you start anodizing your parts. You can check out the above, as well as pick the colors you like best. If you test out some colors, you'll also learn just how long or short you need to work with the color solution.

Color:
So now it doesn't conduct electricity, and is ready for color. It's been rinsed and waits eagerly to change to a new look. Don't wait too long to do the color, due to that oxidizing thing again. You want to mix up a strong solution of dye and water, in a container that can be heated. The solution needs to be at low heat, such as on the stove, so bread and cake pans work well. Again, you need something that will fit the whole part, but it's okay if it touches the bottom this time. I would recommend turning parts every few minutes just to make sure that you get all-over color. Inform your mom or wife that the pan can (and will be) washed out. It is important that the heat be low enough. If the solution gets too hot, you will seal the surface, and it will no longer take any color. (See, told you to rinse it in cold water!) Leave it in the dye until the part is slightly darker than you want it. The next step is to seal the surface of the metal in clean, boiling water. This will leech a bit of color from it, thus the slightly darker color in the previous step.

End Notes:
Also, this process is for aluminum. I don't know how, or if, it will work on other metals. (I doubt it.) Anodizing only works well on rock metal like bar or sheet stock, as opposed to castings. If it was forged or machined, it should have the density to take color through this process.
Something to consider when looking for a charger, is how many amperes it puts out. Without getting into any mumbo-jumbo, anodizing relies on 10 to 40 amperes per square foot. For small brackets and such, this is no problem. The larger parts however, may need the higher levels of amperes. The other note about part size, has to do with how long you leave it in the solution. Above it said 10-15 minutes, but that is for a smaller part. The larger parts may not only need higher amperes, but more time as well. I would recommend an ohmmeter, but again, I have one already.

So there you have it. Quick, fairly easy, and not too expensive. If you don't have the charger, then your first anodizing session could cost as much as sending your parts out to be done. But, then you can do it again for much less. Or do your buddies stuff. Or talk them into chipping in on a setup for all of you to use. We all know ways to help make things cheaper.
And the stupid statement required to cover myself... If you try this and something gets messed up, or someone gets hurt, you are on your own. Deal with it, you can't blame it on anyone else.


Mon Apr 04, 2011 6:07 am
Profile
Founding Father
User avatar
Founding Father

Location: Woodinville
Joined: Fri Mar 11, 2011
Posts: 4631
Interesting article but I think I will stick to cloning anodizing by using powder coat instead. Same look but with better durability and no chemicals.

_________________
"There's two things in life you can't take back... Bullets and words. So make sure you hit what you aim at and make sure you mean what you say."


Mon Apr 04, 2011 8:58 am
Profile
Site Supporter
User avatar
Site Supporter

Location: Mohave Valley Arizona
Joined: Fri May 20, 2011
Posts: 13371
Real Name: Casey
COOL!, I'll have too look more into this, I'm not sure why the coloring comes last....you would think it would come first (or during the electroplating???

_________________
Actor portrayal, Action figures sold separately, You must be at least this tall to ride, Individual results may vary, Sales tax not included, All models are over 18 years of age, upon approval of credit, Quantities are limited while supplies last, Some restrictions apply, Not available with other offers, At participating locations only, Void where prohibited, Above terms subject to change without notice, Patent pending.


See my blog: http://tincanbandit.blogspot.com/


Sat May 21, 2011 5:57 am
Profile WWW
User avatar

Location: Rochester, WA
Joined: Thu Aug 4, 2011
Posts: 84
You can get battery electrolyte at most auto parts stores, they have it behind the counter in boxes and you have to ask for it. I bought some a few years ago for a motorcycle battery and it was about $20/gal.

_________________
The trouble with quotes on the Internet is that you never know if they are genuine. —Abraham Lincoln


Sat Aug 13, 2011 11:45 pm
Profile
Display posts from previous:  Sort by  
Reply to topic   [ 4 posts ] 

Who is online

Users browsing this forum: No registered users and 23 guests


You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum
You cannot post attachments in this forum



Rules WGO Chat Room Gear Rent Me NRA SAF CCKRBA
Calendar


Powered by phpBB® Forum Software © phpBB Group
Designed by ST Software for PTF.
[ Time : 0.622s | 16 Queries | GZIP : Off ]