Fan for mirror Surface on Solid Tube Dob

Does anyone have any experience/recommendations/or other about mounting a fan on a solid-tube dob to blow across the mirror face? Seems it was discussed a while back, but I cannot resurect it.

Jud Mitchell

HI Jud,
Better to force air from below and that will make a vortex on the mirror edge that will scrub the mirror.
The fans is mounted on the end with a plate like this one. The plate seals the tube so that all air that goes in must go by the mirror around the edges, which then carries the warmed air up the scope like a chimney.

Attached Image: