I think I could make this one a little better, but only at the cost of making it much harder to watch prints in progress.

It’s got an outer frame of bent 3x12mm aluminum strip that clamps itself to the the top of the printer, and then an inner chamber of mylar over coathanger wire that rides on the x-gantry and keeps most of the hot air down next to the bed and the print. The cooling fans for the hot-end(s) and the print itself take their air from the outer chamber, which is noticeably cooler than the inner one, at least in my cold basement.

I’m particularly proud (which probably means it’s a bad idea) of the clip that holds the front of the inner chamber. It’s made of PET, so it has enough elasticity to clamp around the huge linear bearing at each end of that big plate, and it’s shaped so that it fits between the body of the printer and all that nasty moving stuff.

So, does it make any difference? Absolutely. With no chamber, the area around the extruder during a print gets up to about 25C. With the outer chamber in place, 30-35C. With the inner chamber in place, 45C.

Oh, does it make any difference in how the prints turn out? That’s harder to tell. I did some quick test pieces and saw less warping, slightly better surface finish and lots better adhesion to the bed (which was at the same 100C with Elmer’s glue stick each time). No cracking, but that might just be because I finally got this roll of ABS dialed in.

Maybe now that I’ve finished documenting the thing I’ll have time for some longer prints (Although I don’t really want to bother doing really long control prints with the chamber off because I already know those don’t work so well.) Anyone else wants to try one, it’s over at Youmagine. Let me know if the instructions make sense.