MrTitanium with a Lead Pipe on the Patio

March 17, 2009

Original Clue Board GameIf the title didn’t give you a Clue, then I just have to tell you that I like metals. I like melting metals. And I finally did a video of  metal melting.

Why? People are always asking me about how light titanium metal is. I was inspired by Theodore Gray and his Periodic Table Table to collect a set of samples of representative metal bars so as to show people. To let them feel for themselves. I now have a small, portable Metals Museum.

I started with Tungsten, because it is as heavy as gold and the hardest one to shape. I then collected and shaped matching bars of aluminum, titanium, bronze (95% copper), steel (97% iron), and magnesium (lighter than carbon). But absent the lead, I can’t illustrate how much heavier tungsten (gold and platinum) are than lead. Pity I don’t dare use silver, gold, or platinum bars. They would be fun exemplars, but I fear short lived.

But lead (Pb from the Latin Plumbum, as in plumbing, plumb-bob, etc) is now harder to get. This useful material has been in household use for almost 6,000 years. Children who likely drank from lead vessels gave us every advance in our civilization. But about a generation ago, it was declared toxic. So now it is getting hard to find outside of radiation labs, and expensive there.

So, I decided to cast my own piece of fresh lead plate from some crusty and oxidized 19th century lead pipe. To feel the pipe is to understand its utility as a weapon; heavy and rigid, yet soft.

Unfortunately, I didn’t set up my camera to show me chopping up the lead pipe. I used a hammer and chisel to get through the crustiest parts (hundred year old drain pipe, eww). But tin snips work well on 1/4″ thick lead. It cuts like cold butter. But shiny.

And the piece I ended up with evoked a geological feature I’d visited: Shiprock in New Mexico. Magma oozed up through a crack in the Earth’s crust forming a vane much like you see on my cast plate.  An accidental demonstration in practical geology.

Can Titanium Be Worn with Other Metals?

June 3, 2008

I received this email:

Dear Sir,
I would like to know when titanium and gold accessories are worn together, will there be any chemical reaction affecting both metals. I am wearing a Gold Chain now and I wish to purchase a Titanium Chain but I do not know whether there will be any adverse reaction. As I know Gold and Silver accessories can’t be worn together, so how about titanium and gold?

I hadn’t previously considered that gold and silver might react on the skin. But, yes they do. It isn’t much of a reaction, but it is to the detriment of the silver.

I replied:

Titanium is safe to wear with other metals.
Titanium always has a protective oxide coating that prevents any electrolytic reaction with other metals. Basically, moisture cannot reach the metal itself in order to complete a reaction. If it is scratched, the protective coating immediately re-forms (unless in a perfectly inert atmosphere (argon, krypton, etc) or a vacuum). That’s part of why titanium is such a good candidate for medical implants.

Go ahead and try it:

In detail, any two metals in a conductive solution (impure water) will exchange ions. If the metals touch, then an electric current forms, eating away at one of the metals. That’s how a battery works. Body moisture acts as an electrolyte between silver and gold, and hydrogen is produced at the gold side, and oxygen on the silver. Silver oxide is black and soluble; it tarnishes and eventually eats into the silver.

But for the reaction to continue, neither metal can be allowed to grow a continuous, non-soluble insulating layer. Titanium and niobium grow very good insulating layers when just exposed to most electrolytes. In fact, I force this insulating layer with enough voltage to produce the colors. That’s called “anodizing.”

Hypoallergenic: Titanium versus Niobium

April 2, 2008

There is a bit of confusion about which of these metals is safer for sensitive ears, or wherever. Niobium is generally available only in a chemically pure form, whereas titanium is available both pure and in a bewildering list of alloys (such as many surgical implant grades).

I list a few of the more popular grades and designations of titanium here. Most of them are hypoallergenic. Most of the jewelry that I sell is pure grade #1 or #2 titanium. Some of my ball posts are an alloy, medical implant certified, and with no detectable trace of dreaded nickel.

The etching and anodizing process strip the few percent of non-titanium elements from the surface, and then create a protective shield of titanium dioxide.

Chemically speaking, titanium is less likely to be absorbed by biological systems than niobium. Neither should cause an immune response or allergic reaction.

But when it comes to piercings, part of the issue is abrasion. Titanium is a hard metal that could have a slightly rough surface on the microscopic scale. The act of putting it in might abrade a tight hole.

Niobium is a softer metal, so the surface will yield more to pressure. This might make it better for extremely sensitive skin. The same softness is why the initially brighter colors of niobium don’t last as long as titanium colors.

Whereas I am distinctly a titanium partisan, my colleague at prefers niobium, from her personal experience.

When in doubt, try both. If both work, then choose only by price, color and design.