Hi, i have 4 TP-Link Deco E4's & on is in my brick built garage that backs onto my garden. I would like to mount a unit on the outside wall of the garage for better signal but wasn't sure what the best material to mount the unit inside of. Now, i assume plastic, but is there better plastics than others.  I do have some spare 110mm waste pipe with a blank end & a screw on cap that would be fully waterproof. Would this work. ?? The reason i am asking is i am building a model garden railway & at least 18 item will work of WiFi.

Thanks