3D printers can't print nuclear weapons - but they can cause a lot of public confusion

Imagine my bemusement when I saw this Washingon Post article on Twitter, titled "You can print your own guns at home. Next it will be nuclear weapons. Really.", written by LSU political science professor Daniel C. Tirone and his graduate student, James Gilley. Here's the relevant paragraph:

When should we expect to see WMDs that can be printed at home? 

...Most important, laboratories have already printed at the molecular level using base atoms — which can lead to printing nuclear materials. Such printing will probably migrate out of the lab within 20 to 30 years. These trends will accelerate with improved printer resolution and advances in the types of materials used. Within the past two decades, 3-D printers have gone from being formidably expensive laboratory instruments to desktop boxes that cost less than $1,500. Prices will keep dropping as the technology advances, so private users will one day be able to afford more complex printers that can produce chemical, biological and nuclear weapons.

After some conversation on Twitter where chemists (including Barney Grubbs) began to critique the author, the article was changed to read the following:

...Most important, laboratories have already printed at the molecular level. Continuing progress in this area could allow for subatomic printing using the basic components of atoms – which can lead to printing nuclear materials. Such printing will probably migrate out of the lab within 20 to 30 years. 

You will be wildly amused to discover that the link to "printed at the molecular level" links to an article in a student newspaper describing UIUC chemistry professor Martin Burke's flow synthesizer in rather breathless terms as a 3D printer of molecules.

Where to start?

First, Tirone and Gilley's prediction is very, very unlikely to come to pass. It belies a complete lack of understanding of the science behind 3D printing. I think Prof. Grubbs has done a much better job explaining it than I ever could, so I think folks should go over there for his explanation.

I have a different question: why does 3D printing make people speculate so wildly?

This is not the only case. Prof. Lee Cronin's work making 3D printed reactionware set off a lot of press about the 3D printing of medicine. I learned about Cambrian Genomics' technology because a Wall Street Journal interview with a manufacturing expert described them this way: "They built a machine that 3-D prints DNA."  Nope, not so.

I think the answer may be that 3D printing seems both futuristic and tangible enough that people can imagine the different things that can be done with it, even if they are not economically feasible or even scientifically plausible.

The Burke team did indeed reference 3D printing in both the HHMI and UIUC press releases. They did not make the claim that the Burke synthesizer was a 3D printer, but that did not stop the popular press from running with this incorrect analogy. Should we ignore the inevitable misunderstandings, or should we prevent them from happening in the first place? What words should evince caution before they are used by public information officers and principal investigators? "Cure" is one - I think I have a case that "3D printer" is another.