On 27 May 2016 at 07:21, V G wrote: > - Anyone have any starting advice? I've copied to a friend with some experience with similar. I'd use FR4 if dust was the only issue and add an extraction system that met my needs BECAUSE FR4 is specified for it's characteristics and anything of lesser rating is liable to be also less useful. These may not matter to you but: Fire retardant Good mechanical stability against warp and bend and ... (not perfect) Strongish stiffish - flex depends (of course) on thickess and loading, but good stuff. Dielectric constant probably doesn't bother you, but maybe. Good longevity - water / humidity resistance , ... more ... Russell --=20 http://www.piclist.com/techref/piclist PIC/SX FAQ & list archive View/change your membership options at http://mailman.mit.edu/mailman/listinfo/piclist .