The titanium story has been wooing select investors for years now.

After all, they may ask, given the clear strategic significance of the metal, and the undaunted expectations for meaningful future demand from commercial airliner manufacturers like Boeing (NYSE: BA), what's not to like?

These factors have emboldened a loyal flock of titanium investors to expect great things from leading suppliers like Titanium Metals (NYSE: TIE). Accordingly, the investors at Motley Fool CAPS have awarded TIMET a five-star rating, with more than 2,500 members casting their votes. Looking back over the years, it's easy to spot an historical basis for their enthusiasm.

Indeed, for any fortunate Fools who happened to pick up shares in TIMET for less than $0.25 back in late 2002, that investment would have multiplied 80-fold by now. If slightly less dramatic, the long-term charts of competitors Allegheny Technologies (NYSE: ATI) and even recent laggard RTI International Metals (NYSE: RTI) tell roughly the same story.

But the past is, well, history. Following a 150% liftoff of TIMET shares over the past year, it becomes increasingly important for remaining investors to chart the likelihood of sustained strength … and here, we run into a bit of difficulty.

TIMET managed to double second-quarter profit to $0.11 per share, despite logging only a 3% increase in net sales year over year. Gross margins expanded, thanks to higher capacity utilization and lower raw material costs, but spot prices for titanium products unfortunately remain below those of the year-ago period. Competitor RTI International Metals noted a 13% year-over-year slide in realized titanium prices, from $22.23 per pound to an uninspiring $19.33. RTI reported a similar pairing of surging profit with barely improved net sales.

Over in the steel industry, we have seen producers like Steel Dynamics (Nasdaq: STLD) and Commercial Metals (NYSE: CMC) report persistent weakness in demand for fabricated steel products, owing to this never-ending housing and construction slump. Although demand for fabricated titanium reflects upon a completely different set of industries, I can't help but raise an eyebrow when I see RTI's fabrication segment suffering an operating loss, despite a major one-time boost relating to the Gulf oil spill containment effort.

I don't mean to douse titanium investors' fiery hopes. I just want to ensure that the apparent investor enthusiasm in the sector remains entirely well-researched. Reading only TIMET's market commentary, a Fool might expect no hint of softness in the market for this hard metal. On the other hand, RTI warns: "the amount of titanium inventory in the commercial aerospace supply chain continues to negatively impact spot market demand". RTI also states that "near-term, caution is warranted." I heartily agree.

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Fool contributor Christopher Barker can bend titanium with his bare hands, provided it's rolled into a thin foil. He can be found blogging actively and acting Foolishly within the CAPS community under the username TMFSinchiruna. He tweets. He owns no shares in the companies mentioned. Titanium Metals is a Motley Fool Stock Advisor pick. Try any of our Foolish newsletters today, free for 30 days.