hi:
I am planning to run the dust collector duct work for a future table saw under a concrete slab. Just dig a trench, place (sealed) duct work and fill over with sand? I suspect the sand fill is tantamount to a liquid over the long term so if the ductwork doesn't crush in say 24 inches of water, it won't crush in a few inches of sand under a slab. Is my thinking correct here? Or are there any gottchas? Ductwork is 6 inch diameter 30 gage.
Thanks
Jonathan