I am hard at work on a pile of ideas for the new year. I was working diligently on one of them, a piece which is arguably more complicated than what I have to share with you today, but I was forced to take an unscheduled break to order some last minute tooling. So while I waited for the mailman to bring me my supplies, I took a small detour, and now here we are.
So although a bit unintentionally, my first work of the new year is an experiment using Titanium. It is a metal I have never used before and I have been wanting to experiment with for some time now. It has some very interesting properties, some fun, and others just a bit scary. But I took the leap and bought a piece of titanium stock a few weeks ago, and so it is what I turned my attention to in my down time.
Lets start with scary properties first, as it is still really interesting. Unlike every other metal I use, it turns out that titanium can catch on fire while being machined!!!! The metal is a very poor conductor of heat and because of this, a dull cutter can readily create enough friction to heat the metal to its flash point.
To top it off, since it is a combusting metal fire, throwing water on it, or using a fire extinguisher will actually make the fire much worse, so there are very few options if it does start up, except to spread out the turnings and let it burn itself out. So keeping the turnings clear so as not accumulate much of a pile, lots of extra care, and plenty of coolant were the rules of the day for this experiment.
I did have one small incident when a cutter chipped and a small turning went up, but it quickly burned itself out, sort of like a small firework coming out of the lathe. Luckily we are talking about really small amounts of the stuff for this project, so there was never too much real danger of things getting out of hand, still very interesting to work with.
Although it is a rather light weight metal like aluminum, It is a great deal stronger and rather tough stuff to machine. Also, being such a poor conductor of heat, drills and cutters heat up rapidly, which shortens their life if not properly cooled. But again for a small project like this, I just took my time, and lighter cuts, and it went pretty smoothly.
The last and arguably most interesting property of titanium is that it can be anodized. The process is a bit different than the aluminum anodizing that I am used to. It differs mostly in that there is no dye involved, and that the color actually comes from light bending as it passes through the oxide layer thats created in the anodizing process. Often described as how a slick of oil on water creates the rainbow effect we are all familiar with, the color you get is dependent on the voltage used during anodizing.
The range of colors you can achieve tracks very closely with the oil slick analogy. If you are interested you can read more here.
In any event, i had never tried anodizing titanium before and this first attempt was reasonably successful. I did learn that waxing the finished part will mute the color quite a bit, but I am still quite happy with the final results, I was able to get a blueish hue on the work on the left, and a deep purple on the right.
(Dimensions on these are 1.5" Diameter by 2.2" inches long)
With that little project complete, I am back to working on my larger project, the parts pile I have started can be seen above. I hope to complete this project in the next 3-4 weeks.
Some additional work in progress shots from yesterday. It is quite an elaborate set up to hold these pieces in place for machining, which gives me a number of ideas for future works.
Anyway, see you again when this next one is complete.
As always, comments and questions welcome.
