Aluminum Can, Saltwater and Charcoal Battery

Step 2 Preparing the Anode

Okay, first we're going to remove the surface treatment from the inside and outside of the can. It's not clear to me that the outside really needs to be stripped but hey it looks cooler that way. There's another instructable in which the author demonstrates a really cool way of cutting the bottom off of a soda can smoothly. The arrangement is shown but didn't work very well for me so I resorted to using household scissors.

Cut the soda can by whatever means about 1.5 inches high or about 1 inch above the lower rim. Using your sandpaper sand the inside lightly to remove any anti-oxidant coating.

Prepare enough warm salt water solution to fill the container. Use warm water and enough salt that it won't dissolve. Stir the solution to faciltate dissolving the salt and set aside.

In the Mark II I will be attaching a copper lead to get a good electrical connection with the can. Since aluminum cannot be soldered we're going to secure our drain mechanically with tape. We're going to use Duck Tape which was invented during WW II by Johnson and Johnson when the U.S. Navy needed a durable waterproof tape for use in the field. I understand this position is akin to posing a solution to "who writ Shakespare" but there you have it.

Comments

[Aritusa]

Actually aluminum can be soldered, check out this site for an easy solution www. solder-it. com they have an aluminum soldering paste that also works with soldering aluminum to dissimilar metals. There are also special brazing rods for aluminum.

[egbertfitzwilly]

How to solder some of the more difficult metals such as aluminum would make an excellent and extremely useful instructable. I don't think most of us have ready access to welding equipment unless I can make an easy arc welder from like a boatload of aluminum cans....

[steam_cannon]

Here ya go. :) Quick and easy brazing aluminum, copper and nonferrous metals

[Speedmite]

Aluminum has a extremely low melting point. You can melt it over a small fire. If you had a really hot soldering iron, you could probably work with that.

[static]

The AlL "brazing" rods available only need a common simple propane torch to use, for small projects that don't sink the heat away fast. Their down side can be cost. Unless you find a motivated carnival/fair demenstrator with a large stock of the stuff to move. For most tape or alligator tips would work well enough.

[germeten]

Alumalloy welding rods, let you weld AL with just a propane torch. Bend-&-crimp works too.

[minkette]

Possibly the sanding down of the can is required to get to a layer of 'pure' aluminium - I vaguely remember at school learning that aluminium is naturally soft and reactive, but the reason we can use it for its strength is that aluminium oxide naturally forms all around it like a protective shell and aluminium oxide is really hard.
So it's like you're cleaning the rust off ^_

This is just a hypothesis though, I'm no chemist!

[themaninthemoon]

Upon failing to find a suitable solution to soldering a wire lead to the can, you can bolt it on, but please be sure to use a stainless steel bolt, nut, and washer. It will cause an adverse chemical reaction to utilizing a regular steel parts. Or you might try to use a two-part epoxy, and a clamp to secure the lead. I used a cut and flattened aluminum pop can to cover a T-shaped hole in a 12' aluminum rowboat. The hole had been caused by someone not cleaning the hull after a 12V, acid battery had been spilled into the boat by accident. Like water it sought the lowest level to accumulate. It has not leaked for the last four years, (at least not from that spot). I smeared the inside of the hole with the epoxy, placed the semi-flattened can (face up) over the hole, placed more epoxy on top of that, then used the plastic bag from the store to cover it with, and placed a large and heavy weight on top to completely cover the area. The next evening I returned, I took off the weight, peeled back the plastic bag, and voila! I didn't even have to sand the patch, it was that smooth. So, I believe that you could use a pair of small, needle-nosed vise-grips to clamp the wire lead into place, and epoxy either side of the vise-grips to get a secure connection. Great article, how many of these do I need to recharge my 12V deep-cycle batteries that I use for the trolling motors on my boat?