Saturday, September 25, 2010

Just a little Mad Kitchen Electrochemistry...

Recently, I ran across an interesting Instructable on Anodizing Titanium. Now, as anyone who has read my website knows, I build combat robots, so I have Ti (or as robot builders call it, "the other white meat") coming out the wazoo. So I thought it would be interesting to try and see how it worked.

The setup is pretty simple. You have a tub filled with an electrolyte solution (I tried 5% White Vinegar, and a saturated solution of baking soda in warm water -- the baking soda works much faster and gives better results IMHO). You then hack together a couple of 9V battery clips so one of them has the black (negative) end connected to a clip, and the other has the red (positive) end connected to another clip.

In my setup, the negative size of the circuit is connected to a large metal plate (it can be any conductive metal; steel, aluminum or even titanium) wrapped in a couple of layers of paper towel. The electrolyte can soak through this, but it prevents a short circuit.

You then connect any number of 9V batteries together in a zigzag manner, and connect the two clips to the exposed ends. This gives you a source of 9V, 18V, 27V and so on. Use rubber gloves and care, because the voltages can get up there!

You then connect the red (positive) side to the item you want to anodize, drop it into the electrolyte, and wait. Bubbles will form; what is happening is that the current is breaking the water up into hydrogen and oxygen, and the oxygen travels to the positive side of the circuit and builds up an oxide layer on the titanium. The more voltage, the deeper the oxide layer gets, and different depths = different colors.

Here are some color results I got; the top row is vinegar, and the bottom row is baking soda. Baking soda is much more conductive, so you get results much more quickly (and the batteries will get warm). I also think it gives a better finished result. Even though I did my tests for 2 minutes with vinegar and one minute with baking soda, you need much less time to get to the point where the color is no longer changing.

As it happens I had some Brunton MY-TI folding sporks lying around. The bowl is made of titanium, and the wire handle is steel. So I decided to see what would happen...

The leftmost spork is untreated, the center one is the result of using 2 9V batteries (slightly used, so about 16v), and the rightmost one required 4 9V batteries (also slightly used, about 34v). Interestingly enough, the titanium stem with the Brunton logo on it has a surface treatment that greatly slows the anodizing process; you can just barely see a hint of color in the purple spork.

All in all, I think a tastefully anodized titanium spork is "an elegant utensil, for a more civilized age" -- and if you sharpen the tines, it's also a weapon!

Thursday, July 22, 2010

High Speed Liquid Observation Platform - Fluid Deployment Bus

As part of my preparations for the September Zero-G flight, I started thinking about improvements to the High Speed Liquid Observation Platform (see 2 posts prior to this one for details on how it works. In particular, I became concerned about the problems of quickly deploying the water globes during the microgravity cycles.

My problem is this: each phase of the flight consists of 5 cycles of microgravity followed by double-gravity. Each half-cycle is about 20 seconds long, so I have 20 seconds to deploy, film, and recover water globes, followed by 20 seconds flat on my back in 2G to reset for the next cycle.

This presents a significant problem, since the reset involves stowing the deployment devices used in the previous cycle, and prepping the new devices (including unsealing them so the water can be released). Not only that, during microgravity, I have to be able to position myself, control the camera, and deploy up to 2 water globes (so I can hopefully collide them).

Yikes. That's a lot of logistics, and since one hand has to control the camera rig, I only have 1 hand and 2 legs remaining with which to do all this.

After a lot of thought, here's what I came up with:

The steel ring is where the diaper-lined plastic bag that collects the water globes will go, and the baby soda bottles are the deployment devices.

Each BSB (these are 2-liter soda bottle preforms, damn near unbreakable) has a rubber stopper in it that has a tube running through it. The tube runs down to the bottom of the tube. The way it works is simple -- you uncork the BSB, and stick the tube that extends past the stopper into your mouth. Gentle puffs then push the water out of the tube.

The tubes are angled and positioned so that a water globe, after being deployed, should float on a path that takes it right through the camera's field of view at the proper distance. And if all goes well, two simultaneously deployed globes should hit each other at just the right place.

During the 2G period, reset involves either restoppering the tube or tucking it through a loop to keep it from floating loose, then unstoppering 1 or 2 bottles and putting the tubes in my mouth. I have timed this process and my first attempt took only 12 seconds.

Of course, I have no guarantee that this deployment method will actually work, so I'll have other methods available just in case. And I also need to think about how to keep myself stabilized and still be able to easily position myself in order to track the wandering globes of water.

But that is the subject of another post.

Sunday, May 30, 2010

T-4 Months and Counting

It's been a long time since I've had anything to report on the blog, but the wait is over.

As readers will know, I have a standby ticket-to-ride on G-Force One. Well, I got a email from ZeroG the other day offering me a slot on one of their upcoming Research flights. These are special flights with fewer people on board, and the ability to deploy significant experimental apparatus. They also do more parabolas than a standard flight (25 vs. 15).

This means I'm going to be able to do more interesting stuff than on a regular flight. The hard part is going to be figuring out how best to use the time.

Which is where you come in.

I talked to the ZeroG folks and they have agreed that I can invite people to build experiments, and if they pass muster with ZeroG, I will fly them for you and film the results. I am particularly looking for projects that involve science outreach to young folks, so this would be perfect for an engineering summer camp project.

If you are interested, please email me ( -- and pass this on to anyone you think might be interested.