Here is a New System to install a glued on skylight for an ALiner, Flagstaff, Rockwood or any camper that uses this mounting style. This is quicker and easier than the other system I previously posted, and should be even more secure and leak proof.
In Video Links -
Custom high grade skylights - https://www.eztopsworldwide.com
SikaFlex 221 Adhesive/Sealant - https://www.amazon.com/dp/B00NW5LWHA?ref=ppx_yo2ov_dt_b_product_details&th=1
Eternabond Double Faced Tape - https://www.amazon.com/dp/B004IZCRGS?ref=ppx_yo2ov_dt_b_product_details&th=1
Note - This is an experimental system to replace a skylight. I cannot guarantee how effective it will be for you, or longevity of the seal integrity.
