Many schools require three rec letters in the application. Would it be ok if I chose all three recommenders who are not from my undergraduate department (ChemE)? The reason is simply that I feel I can't get solid letters from them. The professors currently on my mind include a guy who I did work-study with in a pharmacology lab, a professor who I did research with over the summer at another university (MatSci), and another who I took two courses with (MatSci). I am applying to both chemE and material science programs. Any thoughts are appreciated.
This is just my off-the-cuff impression, but I don't think it will raise eyebrows to have recommenders from materials science, particularly since your interests seem to be somewhat interdisciplinary (since you're applying to both materials science and chem E departments).
what about getting a recommendation from a person who isn't a professor but a lab manager? I feel that he knows me better because I work directly under him and report to him but would his title lower his credibility?
I would have it written by a professor, very preferably -- in many cases, if the professor feels the subordinate (lab manager, postdoc, grad student) will write a stronger letter, the subordinate will write the letter and the professor will edit and send it.
Still, I had a letter written by a postdoc, which did not seem to be a liability for me when I applied.
