Horizons Unlimited - The HUBB - How to protect your gear from turning black from Aluminum?

Quote:

Originally Posted by Wheelie (Post 619518)

Anodizing is a very simple, dirt cheap and easy process - also for the DIYer (I have never tried anodizin large aluminium items). It will leave a thin layer that is much harder than the aluminium. It doesn't crack or chafe, nor does it rub off or "rust".

You will need:

a simple and cheap battery charger that will not easily turn off the fuse.
A large non-conductive container (plastic) to house the item to be anodised
A anode (your item to be anodised) and one or more sacrificial cathode (i.e. lead plates sourced from an old car battery - thorughly cleaned and sanded (poisenous - cover up and wear a mask)
Conductive liquid (electrolytes) with cleaning and etching propertie, i.e. a caustic soda and water mixture
a non conductive prop (wooden stick) and something to suspend the item to be anodised in the liquid filled container (steel wire)
some copper wire want to

Method:

Suspend the item to be annodiced in the non conductive and liquid filled container
Suspend the cathodes at approximately equal distances on all sides of the item to be anodiced - in your case one on each of the short sides, and one or two on each of the two long sides, and one or two inside the case
Hook the positive lead to your anoode, and the negative to your cathode. You will not want to subemerge valuable leads below the liquid, but instead use a copper wire - this as you don't want your charger cables to be neither sacrificed or annodised

You could if you want, anodice the item with color - i.e. in the color of your bike.

This method can be used to remove paint or rust from metal - leaving a rust protective layer - which is the only thing I have used this method for - even on items as large as a pannier. I have never anodiced aluminium.

For your intents and purposes, you might only want to anodise the inside of the pannier. In this case you would drop the container and only fill up the pannier (which you would have to set on a non conductive material, like a rubber mat).

I don't think lining your bags with anything that is not perfectly smooth, puncture free or waterproof - is a good idea. Water, smells, oils, dirt - will be absorbed into it - and cleaning it will be a hasstle.

Another option is to look into "helicopter tape" (automotive protection film).
This stuff was invented to put on helicopter rotors leading edge to preserve them for all the dirt and grit that pass through them on landing and take offs - significantly reducing the frequency for which rotors need to be replaced. It is tough, is applied and removed easily, and stretches to contours. You can buy it in sheets or tape forms. It is clear. It's not prohibitively expensive. Personally, I think I would have tried this route first - unless you can find a very thorough instructional video on anodizing panniers - and that is easily replicable to you.

If you go down the anodizing route - be very certain that you do not hook up the wires incorrectly - or you will sacrifice your panniers and be left with a beutfylly anodised led plate.

If you go down the anodizing route - the mix of electrical output, time or ammount of electrolyte will vary. If power or electrolyte is weak, you will require more time. It can therefore be a good idea to start easy and add a stronger solution of electrolyte and/or increase electrical output if you see no results after a day or two, and even more on day three or four, and so on. Maybe you have a perfect result in a matter of hours, maybe it will take a week. In any case, go onto youtube and research.

Basically you are right and why I did anodizing years ago, here is what I remember about the process. And it´s also the reason why I would never do it again by myself with panniers. Surfaces are too big and the shape of them is too complicated for surface handling. For panniers the goal must be to reach a really thick anodized coating because otherwise thin anodzing films will be damaged outside by scratches/dust/sand and inside through rubbing of load easily.

Before you can start to anodize all metall area need to be clean, sanded and polished. Every kind of existing surface coating like paint or little scratches will ruin your results.

When you work with Sodium hydroxide and with Sulfuric acid you have to take safety measures. You will need a good ventilated room because during the process Oxyhydrogen will be produced which is higly inflammable and explosive.

After sanding and polishing you clean the metall surface with a mixture of destilled water and drain cleaner (Sodium hydroxide) which you normally use in your household. You can buy special and expensive products for metall surface cleaning and the advantage is that they keep the ph factor leveled. Which will influence the quality of the anodizing process. Also you use Sodium hydroxide to remove an anodization layer if you failed.

A destilled water bath will be needed after every process for cleaning the surface.

Sulfuric acid will be the fluid for anodizing, it´s nothing else than battery acid which always contains 37,5% of Sulfuric acid. For anodization a percentage of 15-20% is needed, so you have to mix it down with normal water. And of course you will need a colour for the coating.

Down in the anodizing bath you use lead which is comes from the roofing business and can be bought in roles. This will be your cathode.

For the anode best to use is a piece of titan in form of a stick. Also for fixating all metall piece you want to anodize you use titan wire. Why? Because all other metalls will react chemically or disolve in the process.

For controlling the temperature of the anodizing fluid, you can use an air pump from a fish tank with a perforated tube. Temperature in fluid must kept under 20°C, if temperature gets higher the anodizing process fails. You can also use thermal packs for this because as colder the bath is as better will be the anodization result.

You need a power supply which is stablized and used in laboratorys. Will cost you starting from 100€. You need a power supply at minimum of 200W++ and it must have the feature to hold a fixed amperage because the liquid resistance in the Sodium hydroxide will change during the process. If your power supply is not stabelized you have to measure resistance and correct the amperage constantly during the process. This is too complicated and a potential failure task.

The formular for calculating amperage is: for 100 square centimeters of metall you need 1,5A per hour. Now think about the inside and ouside surface of panniers to calculate power and size of your power supply! If your power supply is under powered you have to extend the time of process which makes it more complicated. You also need titan wire to supply electric energy and their quadrat diameter has to be in relation to the needed amperage.