MOTM

Hi all - I built a two row case (20U in each row) for my MOTM-based  
modular.  In it now are a 900 PS, a 440 and a 110; finishing up an  
800 EG kit and will be adding some DIY modules next.  Right now there  
is a back panel that slides on and off but it is rather kludgey and  
rattles at certain bass frequencies.  I'm thinking of just screwing  
it in place, making the case more or less "air tight", aside from  
whatever air passes through the front panel jacks or tiny "slop"  
spaces between modules.  Will I get too much heat build-up in the  
case with no air circulation?  I'd like to keep the dust out as much  
as possible (and not drill ventilation holes in the back panel).  For  
some reason my studio gets rather dusty, though I take pains to  
prevent it.

Thanks,
ld