The fan housing was just cobbled together from wood scraps with hot-melt glue and the odd nail.

It it an open-sided box against the projector's air outflow grill, with an open top at the front for the 140mm fan. After building it, I thought it looked a little chunky, so I chopped off the bottom corner of the part that sticks out, making it into a 45 degree upward slope. Slopped on some white paint and.. there she be.