I have a part-time outside job in addition to being a full-time professor. I'm struggling with performing an analysis that I believe a graduate student would be able to help me with. I suspect the student would be happy to do so, both because of having a nice demeanour and also they enjoy interesting problems and are also applying to PhD programs, so being able to state that they helped me with my research would be to their benefit. I'm not able to easily get my outside employer to hire them as a consultant. Would it be ethical for me to ask for their help with this problem? If I did, should I offer to pay them out of my own pocket (outside salary)? Should I insist on doing so? I'm thinking it would take a few hours. FWIW, I'm not their official advisor, although my colleagues and I share that role in practice.
FWIW, one of the two outside organizations involved in this project is a non-profit, for which some people volunteer the time. (I'm being paid by a for-profit company to do work with a non-profit organization they support.)
UPDATE
After posting the question but before getting any replies, I emailed the student, asking them if they wanted to help, including a link to this question and cc'ing the director of the graduate program and the Provost, as a check on myself.
I just figured out the technical problem I was struggling with, so I no longer need help, and this question is moot. I'll leave this question up, in case it's useful to future readers.