How to find a mentor when your PhD advisor isn't enough?

Question

I'm a third year PhD candidate and have been working in a field that is very cross cutting. For context, my department is chemistry, although my research is very far removed from chemical application.

Red flag 1: I was given a topic, not a project.

My main thesis project involves some topics that are not in my or my advisors direct area of expertise. I don't think my advisor understood the breadth and depth of the topic they gave me. As I came to understand the topic better, it became clear the initial goals were out of reach. There was no way a single graduate student working alone could satisfactorily complete this project. I spent literal months trying to find a tangential question that could be turned into a proper research project. Eventually I was able to land on one that I've been working on since.

Red flag 2: My advisor doesn't have the expertise to advise me on this problem.

My advisor has given me very little in the way of advice, excepting the recommendation of often vaguely related papers I've already studied. In our rare meetings, it's just me updating them on what I've learned and them asking me extremely basic questions. Beyond them, I don't have anyone who knows the topic enough to point me in the right direction and I spend a lot of time getting stuck in rabbit holes without guidance. There are no postdocs or other more senior graduate students to rely on. I understand the PhD is mine to do, but I'm feeling more and more incapable of doing a good PhD on my own.

In all I feel isolated, frustrated, and hopeless as I feel my way through darkly. There are others in my university who have the expertise, but my advisor hasn't really helped me to spur collaboration with them.

I came to grad school to be a research apprentice, but currently I'm just an independent researcher. If I ever finish publishable results, I'll just slap my advisors name on the end without them having any idea of the validity or value of the content. It seems like this isn't so uncommon in chemistry, but it just feels like this is seriously wrong.

How do I find people who can mentor me when my advisor is unwilling and unable to assist me? It feels wrong to have an advisor who at this point feels incapable of actually giving advice. I know that with an advisor who has expertise here that I could make much more rapid progress by getting pointers in the right direction.

Of course the people who have this expertise would have to be willing to train someone from outside their area, and without an advisor to spur this on, it feels like a big ask to get supervision outside of my department. Why would a professor take a struggling grad student from another department when they could just train their own to do what I've been trying to do, but better?

Answer 1

The first step I would take is to schedule a meeting with your advisor. The topic of that meeting is that you would like more input from someone specialized in the other topic. How this can be organized is something that differs from country to country, university to university, and even department to department. It could be that your advisor can invite someone from another department to join your committee, or as a co-advisor, or ...

As to why some other professor would want to advise you:

First, that is not your problem, it is your advisor's problem. Let her/him/them deal with that.

Second, regardless of all the horror stories on this forum, most professors just enjoy talking to someone interested in their field and helping those persons get started. Whether they have time to do so is another story, but at least it is a good starting point.

Third, university is a big bureaucracy. It is a big informal market where favors are exchanged all the time. Tenured professors are in the same organization for a long period of time. It is quite likely that situations will come up where it helps a professor when another professor owes her/him/them a favor.