Removing Anodization

[adairjs]

I have some nice metal pipes with anodized finishes. The only problem is that the anodized finish is coming off at the bottom of the bowl where the tobacco is burned. Don't wanna get that metallic stuff in my lungs. I'm guessing some of you have removed anodized finishes from the aluminum handle scales on knives before. Can anyone suggest a method?

[The Deacon]

You can sand it off, but anodizing is typically harder than the aluminum or titanium under. So, you'll still be getting metallic stuff in your lungs. You might want to consider switching to a wood, meerschaum, or corncob pipe. Or ceramic, if you're smoking something other than tobacco.

[Evil D]

Oven cleaner. Get yourself a can of Easy-Off. I once stripped black anodizing off an RC car chassis with the stuff.

[adairjs]

Thanks to you both. The metal underneath the anodizing is supposedly a zinc alloy.

[Donut]

You can sand it off, but anodizing is typically harder than the aluminum or titanium under. So, you'll still be getting metallic stuff in your lungs. You might want to consider switching to a wood, meerschaum, or corncob pipe. Or ceramic, if you're smoking something other than tobacco.

From what I read, anodizing on aluminum is a coating like you describe, but anodizing on titanium is an entirely different animal.

I've removed it with steel wool, but it takes a lot of work. I've read oven cleaner works good.

Anodized Zinc? hmm, I don't know anything about anodized zinc. =\

[Evil D]

Anodized zinc sounds like a coating over a coating. Never heard of that before.

[SolidState]

1. Zinc anodes are incredibly common - key to the process of galvanization. They can be found as sacrificial anodes in everything from bridges to the towers that hold up power lines. Most chemistry classes teach intro to batteries by placing a zinc electrode (anode) in zinc sulfate, and a copper electrode (cathode) in copper sulfate connected by a wire between the electrodes and a salt bridge between the solutions.
2. "Anodizing" is typically defined as the electrically-activated process of reacting a metal with oxygen to generate a metallic oxide coating.
3. Combustion is generally defined as a process of reacting a chemical with oxygen in the presence of gaseous oxygen. This process often promotes high temperatures in the surroundings. High temperatures speed up the process of reaction.
4. Any pipe is likely to react with oxygen until its surfaces have developed a coating - be that coating non-combustible resins, or metal oxides. Wooden pipes burn until this happens, as do horn. Glass pipes are already fully reacted with oxygen (Silicon Dioxide) so they do not burn. Ceramic pipes are in a similar category, but can release particulate of the ceramic into the smoker's lung.
5. The great majority of metals exposed to oxygen will have at least ten nanometers of oxide coating just by being exposed to air. If this coating does not form, you can brilliantly burn metal - it is a really neat thing to see.
6. The only thing in the anodized coating that might hurt you worse than smoking the clean pipe is any dye within the coating. Adding carcinogens probably goes in the face of your ideas about what you want to inhale.
7. The anodized coating may, in fact, be a galvanic coating, in which case the metal underneath may be worse for you than the zinc oxide coating. Zinc oxide is relatively harmless and can be found in a great deal of sunblock.
8. Zinc oxide is soluble in acid and basic conditions, but a zinc oxide coating will immediately form on the metal during the process of dissolving the old coating off.
9. From the MSDS: Zinc oxide takes almost 8 grams per kilogram of bodyweight to kill 50% of mice. That means that a 220 lb man would probably need to ingest about one and three-quarter pounds of the stuff to face a 50% risk of imminent demise. It isn't super dangerous stuff. It doesn't even melt until over 3000 degrees Fahrenheit, so it is not vaporizing significantly while tied to the metal heat sink of the rest of the pipe.

I hope this helps.

[The Deacon]

You can sand it off, but anodizing is typically harder than the aluminum or titanium under. So, you'll still be getting metallic stuff in your lungs. You might want to consider switching to a wood, meerschaum, or corncob pipe. Or ceramic, if you're smoking something other than tobacco.

From what I read, anodizing on aluminum is a coating like you describe, but anodizing on titanium is an entirely different animal.

I've removed it with steel wool, but it takes a lot of work. I've read oven cleaner works good.

Anodized Zinc? hmm, I don't know anything about anodized zinc. =\

There are coatings and there are coatings. Paint is a coating but, at least when applied to metal, it just sticks to the surface, it doe not chemically bond with it. Rust, verdigris, and other forms of oxidation are also coatings, but they form by chemically changing the outermost layer of the metal itself into an oxide of that metal. I'm fairly certain that anodizing, regardless of whether the metal being anodized is aluminum or titanium, is closer to the second than the first. Will say that, like you, I've never heard of anyone anodizing zinc before.

[Stuart Ackerman]

From Wikipedia...
Anodized zinc

Zinc is rarely anodized, but a process was developed by the International Lead Zinc Research Organization and covered by MIL-A-81801.[11] A solution of ammonium phosphate, chromate and fluoride with voltages of up to 200 V can produce olive green coatings up to 80 μm thick.[11] The coatings are hard and corrosion resistant.

Zinc or Galvanized steel can be anodized at lower voltages (20-30 V) as well using direct currents from silicate baths containing varying concentration of sodium silicate, sodium hydroxide, borax, sodium nitrite and nickel sulphate.[12]

Which comes from this page...
http://en.wikipedia.org/wiki/Anodizing" target="_blank

[JD Spydo]

You can sand it off, but anodizing is typically harder than the aluminum or titanium under. So, you'll still be getting metallic stuff in your lungs. You might want to consider switching to a wood, meerschaum, or corncob pipe. Or ceramic, if you're smoking something other than tobacco.

Hey DEAC from what I can remember anodizing is pretty much the same as bluing a gun barrel from what I've been told. If that's the case then it is actually impregnated and virtually part of the metal itself if I'm correct?

You could use something extremely fine like Crocus Cloth>> because it has a bit of a polishing effect to it as well as a light abrasive action. I wouldn't use anything coarse or even medium because metal scratches are **** to remove.

[bdblue]

2. "Anodizing" is typically defined as the electrically-activated process of reacting a metal with oxygen to generate a metallic oxide coating.

Yes and I believe it is then dyed to whatever color is desired.

[Crazy Fox]

Yes, anodized coatings are a step beyond a paints so they are more resistant to removal.

The whole point of anodizing is that you are GROWING a mechanically strong, chemically inert, and well-adhering coating on the surface of the metal rather than slathering on a paint coating. The anodized coating is a passive film which protects the metal underneath from corrosion, so it will be difficult to remove by chemical means.

Ordinarily, I wouldn't worry about the health hazards of anodized coatings because, being oxides, they are very inert (isn't sand just a mixture of aluminum, titanium, and silicon oxides?), but it would be a different story here since it would be getting small particles of it in your lungs. Hence the concern in earlier posts over using abrasives to remove the coating. Also, if your coatings are made with a dye step for coloration, it may pose additional health issues (toxicity).

I suppose you could remove the coating electrochemically by building a rig with a battery charger, wires, and a tank full of electolyte, but it would be more effort than it's worth.

[JD Spydo]

Oven cleaner. Get yourself a can of Easy-Off. I once stripped black anodizing off an RC car chassis with the stuff.

I've also been told by a mechanic friend mine today actually that Brake Fluid will do the trick if you soak it overnight he says>> he says it will also remove clear coat and laquer finishes as well. I don't think he's lying to me because he is a great mechanic and a very smart guy.

[Evil D]

Oven cleaner. Get yourself a can of Easy-Off. I once stripped black anodizing off an RC car chassis with the stuff.

I've also been told by a mechanic friend mine today actually that Brake Fluid will do the trick if you soak it overnight he says>> he says it will also remove clear coat and laquer finishes as well. I don't think he's lying to me because he is a great mechanic and a very smart guy.

It probably would...brake fluid is nasty stuff, it'll eat the paint off a car door.

[The Deacon]

It probably would...brake fluid is nasty stuff, it'll eat the paint off a car door.

And then start eating the car door, if it's steel.