Some questions of my DIY project

Rhino gave away plans for a $75 DIY slider, using skate wheels, 2 alum tubes, cheap steel angle all simple parts, choose your parts quality as well, but was purely manual push, a good base to add motorization though. Google photo slides.

http://rhinocameragear.com/

If you look at the basic Rhino slider, the movement motor/elec is mounted on the end, and moves the cam via rope/cable, very simple!!

Here is wonderful use of sliders - http://timescapes.org/ It also was the very first 4khd video I saw, He used and wore out several 5DIII (shutters at least), also used HD video cams.

If the components only move at the pace of a snail then thermal worries make little sense, much like drive motors for telescopes or even gimbal systems for video.

As to a cover, put no bottom on it, that way it is shielded from moisture but air can cool it.

OTOH, if it is in the sun for hours, then thermal shielding is wise, all parts w/ electronics including cam and lens !!

But small ac or servo motors moving slowly will produce little to no heat, a few degrees above ambient, unless under constant strain of a load (then maybe too small for job), which I find hard to imagine with just a DSLR & lens.

The control electronics, assuming, should also not produce much heat, but shielding from the sun is again wise, but simple reflective foil (like on moon/mars rovers) is all that your need, as all parts must be able to operate in the ambient temp w/ no issues of course.

GL!