That all aside, the next print failed about 10 layers in
The sooner I get those screws the better!

one word: ebay.

Honestly didn't even consider eBay for screws o:
I'll get right on that

Whilst this is entirely speculative, I'm thinking my filament jams coincide with the zen-drive motor getting quite hot.

Thoughts?

maybe: I don't worry about it. However, others have pointed a CPU case fan at it and are happy with the result (could be a placebo effect though).

From my experience the motor was getting so hot you couldn't even touch it for more than a few seconds and it seemed to jam all the time, as soon as I put the fan pointed towards it the motor just barely gets hot and I have had only a few jams and those seem to be from the back plate on the frozen being too loose but I have since fixed that and I'm happily printing without jams now. This only really seems to help on really long prints, short prints the motor didn't seem to get too hot. I guess this largely depends on ambient room temperature also, my room is a bit warm with all the stuff I have going so my motors may be hotter than most.

If I attached a CPU fan's black/red wires to the 5D board,
where the hot bed power would go, would that blow it up or power the fan?

Could probably find a fan around here somewhere. Just need to figure out how to power it.
If needs be, I could just solder it up to a battery & switch, point it at the zen motor and turn it on/off manually.

If your not already using it there is a fan plug on the D8 that you could use. I don't know that I would try to splice into the hot beds power but I'm sure someone a bit more knowledgeable on the subject would know. I use an old power adapter from a router I had that had the right specs for the fans I'm using and that seems to be working perfectly for me. If you list the specs on the fan you plan to use I'm sure someone could give you a good idea of what your options are.

If you just need permanent on, then solder to the power input board (which I did for the E3D). If you want on/off control, or possibly (fan dependent) PWM control, then use the fan pins on the D8/printrboard .

You can just wire it straight to the power board without anything? And how many fans could you wire to it, I have three fans total and I would rather it all be hooked up to the box instead of having to use a aeperate power source.

Just rummaged round in my box of bits & found an old motor, a broken graphics card fan, a 4.5V battery, some wires & a led light thing which I'm gonna de-solder a on/off switch from. Gonna have to do for now

Time to tear things apart, solder them together & hope.
Hope it works & hope I don't kill myself in the process.
As usual, I'm making it up as I go with very little knowledge of electronics.

A simple circuit shouldn't be too hard, right? *bszzzzttt*

black to black, red to red, no fingers in the circuit!

That was easy.
Need to design a mount, see if I can print it whilst holding the fan.

what kind of strange fan is that? It didn't come out of a PC surely?

T'was from a broken graphics card. I took it apart ages ago but kept the fan
Sadly the motor attached to said fan no longer worked, hence why its jammed onto the end of that random motor I found.