Hey, Guys - I've had the looming project of wanting to enclose and vent my FT5, and after acquiring a second I decided to tackle this project.
My specs were; inexpensive, non-flammable, minimum footprint, easy access and venting. I decided on using a typical wheel blower, the kind on wood stove heaters - continuous duty, low amp, around 50 watts.
I used single strength glass (please don't quote safety requirements for glass cabinets) everywhere, and sanded all the edges dull with a wet diamond stone. In my youth I spent summers cutting replacement glass, so I'm mildly skilled at glass cutting - something any of you could do with a little practice.
I bought all of the glass for both from the local Ace hardware in 24x24 and 24x30 stock sizes. At roughly 1/3 the price for the same stuff from a local glass "company". Any price around $2 a sq foot is great, the "company" wanted $6 a ft, ridiculous. I've got about $140 in glass for the two.
I used double sided tape to hold the panels in place on the inside of the gussets. Piano hinge for the doors and HDMW for the sliding door tracks.
As you can see, my preference for the spool is on the ground and extruder being fed by flex-tube. Works perfectly, never a broken filament and the machine does not have the inertia of the spool moving around on the top. So I made an enclosure for that as well on the top.
My goal was not an airtight unit, there are small gaps everywhere, but the blower keeps a slightly negative pressure on the cabinet and ultimately everything inside is vented out. There's not enough air movement to pull away heat from the bed or end, nor enough to bring in an undue amount of dust.
I'll answer any questions I can. Please don't ask for all the glass measurements - I cut them on the fly and don't have a list. The process of cutting the glass is slow enough that you'll want to confirm your own measurements along the way.
All the best, Don