What is your experience/advice/opinion on working 2 FT jobs?

I currently work as an analytical chemist (my official job title is SR Lab Tech). I’ve worked in my current position for a little over 3 years (including 6ish months as a contract worker). Long term I have aspirations of becoming a Forensic Scientist, and I have been applying for jobs in that field nationwide for some time, as well as educating myself more on the field via classes and textbooks. I have also maintained a part time job on the side, working about 20 hours a week (when you include drive time) tutoring an autistic boy. I need the part time job in order to afford my extensive student loans.

In my recent string of searching for forensics jobs I found a chemist opening locally. It’s a job doing work similar to what I’m doing now (I do more physical chemistry, working with metals now, this would be more organic/pharmaceutical, but still doing QC work using similar principles). The job pays slightly less than I make now, and would be full time like I have now. The catch that has me interested is that they offer second shift. Meaning I could feasibly work my current full time job, and this job.

Originally (and admittedly still now to some level) I was not that serious about the idea of working two full time jobs. But it has dawned on me that with no free time to spend the money, and nearly twice my current income coming in, I could potentially pay off my student loans in 4 or so years, or at least bank some money.

In reality I doubt I would handle such a workload for 4 years. Though I haven’t worked less than 60 in pretty much 4 years, and have often approached 80 when you throw in other commitments; it’s much more spread out (I work weekend hours or have breaks in my day). But the thought occurs to me that I could work the two jobs temporarily while still looking for a forensics position. If I found a forensics spot within the next 6 months, I would be fine dropping both jobs like a bad habit… and I’d be lying if I said I couldn’t use the extra cash it would afford me.

What do you guys think? I have an experience working more hours than this for one extended period in my life, and it was miserable. But the work was far more strenuous, and the money wasn’t even comparable. What’s your opinion, is the half of my brain that says this is stupid right?