FTC folks, I have converted a 2013 XLT into a micro camper. It started out as a cargo van with only two cab windows. I have installed a van in the roof and small RV window in the rear doors using butyl tape as sealant. Now attempting to install an RV window in driver side ”second row” sliding door only to discover that the portion of the door where a window would normally be in a passenger van is not steel. Does anyone know what this material is? Looking for ways to build out the window trim and appropriate sealants. Thanks in advance!
