Anodizing Aluminum
Contents |
Meta-Bits
- Organizer
- punkin
- Participants
- Date
- (Date not set) 2010
- Comment
- This document is a very messy, poorly edited, and unreliable work-in-progress.
Goal
Aluminum is cheap (yay!), but its also soft, and worse, its dirty. Through the magic of electricity (and a wee bit of chemistry), we can harden aluminum's surface, increase its resistance to corrosion, and as a by-product, persuade it to take up dye -- pretty!
Theory
Preparing the Aluminum
Sodium hydroxide reacts with aluminium and water to release hydrogen gas. The aluminium takes the oxygen atom from sodium hydroxide(NaOH), which in turn takes the oxygen atom from the water, and releases the two hydrogen atoms. This reaction can be useful in etching, removing anodizing, or converting a polished surface to a satin-like finish, but without further passivation such as anodizing or alodining the surface may become degraded, either under normal use or in severe atmospheric conditions.
Anodizing the Aluminum
Dying the Aluminum
Sealing the Aluminum
Practice
Materials
Safety Equipment
- Sodium Bicarbonate
- nitrile gloves
- safety glasses
Preparing the Aluminum
(Sodium Hydroxide solution can be re-used for years, if protected from cross-contamination between steps. Add more water to bring the level back up as it evaporates)
- Sodium Hydroxide (NaOH) solution
- dish soap
- 5 gallon plastic tub or cooler
Anodizing the Aluminum
(Sulfuric Acid solution can be re-used for years, if protected from cross-contamination between steps. Add more water to bring the level back up as it evaporates)
- 15-20% Sulfuric Acid solution
- Sulfuric Acid (H2SO4)
- 12 volt power supply
- 5 gallon plastic tub or cooler
- lead cathode
- aluminum wire
Dying the Aluminum
(Dying solution can be re-used for years, if protected from cross-contamination between steps. Add more water to bring the level back up as it evaporates)
- prepared fabric dye solution in desired color (i.e., Dylon)
- large container (metal pot, plastic storage container or cooler)
- heat source (burner, if using a metal pot; aquarium heater, if using plastic)
Sealing the Aluminum
- distilled water
- large pot
- burner large enough for the pot, and hot enough to bring water to a boil
Method
Preparing the Aluminum
Anodizing the Aluminum
Dying the Aluminum
Sealing the Aluminum
Safety
This project involves working with chemicals that can hurt you very badly and very permanently. Before you begin, make sure you have a copy of the MSDS from the manufacturer of your chemicals, have read and understood it, and are following all of the recommended guidelines for safe use, safe storage, and safe disposal. Use protective equipment (gloves, safety clothing, and eye protection) at all times.
Sodium Hydroxide (NaOH)
Sodium Hydroxide is corrosive; if it comes into contact with unprotected human tissue, it will burn very badly, and cause permanent scarring.
- MSDS
- JTBaker
- R-Phrases
- R35
- S-Phrases
- S1/2, S26, S37/39, S45
Sulfuric Acid (H2SO4)
Sulfuric Acid is corrosive; if it comes into contact with unprotected human tissue, it will burn very badly, and cause permanent scarring.
In addition to being corrosive, sulfuric acid has a highly exothermic reaction with water. If you get it on your skin, the heat created by this reaction will cause further burning.
Finally, it will also suck out enough moisture from your skin to cause tissue damage.
- MSDS
- Wikipedia
- R-Phrases
- R35
- S-Phrases
- S1/2, S26, S30, S45
Resources
Materials
- Sodium Bicarbonate
- Any grocery store will sell this as baking soda. We want to have lots on hand, just in case, so look for grocery stores which will let you buy it in bulk. I.e., The Bulk Barn.
- Sodium Hydroxide
- Home Hardware sells a product called Home Lye Crystals (available with the drain cleaners), for about $22/3Kg container. This product is guaranteed to be 90-98% pure Sodium Hydroxide; it contains trace amounts of "something to keep it from clumping", which is not a problem for our purposes.
- biobar/Tekniscience, out of Quebec sells different concentrations of Sodium Hydroxide online. I have not purchased from them before. There may or may not be a HazMat handling fee.
- Sulfuric Acid
- biobar/Tekniscience, out of Quebec sells different concentrations of Sulfuric Acid online. I have not purchased from them before. There may or may not be a HazMat handling fee.
