On trick I learn in making underwater enclosures to keep the epoxy out of the treads is to get a few extra screws and coat the screws with silicone grease or petrolium jelly and tread them into the T-nuts. When you are done the screw will come right out and leave the treads un-clogged. One thing to watch is not to let the epoxy build up around the screw. If this happens and before it sets off you can remove the excess easily with a cotton swab. Hope this helps.