<p>I'd like to attach a piece I printed out of PLA to a small titanium rod. I've previously used Superglue (cyanoacrylate) to glue PLA pieces to each other with great success, but the problem is that if you don't apply it perfectly cleanly, it leaves very noticeable stains on the PLA.</p>

<p>Can anyone recommend a good glue for this application that won't leave stains like that? </p>

I've been a fan of epoxies for unusual adhesion problems. I found on
Amazon a product with titanium
in the name, but there's a caution regarding polypropylene plastics.
PLA is not of that family of plastic, which gives it a good chance of success. Epoxy is typically more viscous than cyanoacrylates, giving you a bit more control of the application, but also creating the need for care with "ooze-out."
The big glue company, Gorilla, also makes an
epoxy
that includes plastic and metal in the adhesion listing.
As PLA is somewhat sensitive to heat, one would consider that fast-cure epoxies generate more heat than slow-cure epoxy, but the amounts you'll be using are not likely to create enough for concern.