Originally Posted by Humble Leader

I have two pelican cases I've drilled through and have had zero leakage. people if you use proper mounting hardware you should not have any leakage. inside of the case use EPDM washers followed by a regular hex nut. 2 cases, 8 mounting holes, zero leaks. EPDM washers are made for applications where weather and moisture resistance is required and will not degrade. do not use silicone, do not use rubber gaskets or rubber washers

if you mount properly your biggest risk of leakage will be through the seams in the case. the pelican protectors are a great case through cold winter and hot sun they have kept their form and never leaked