This is my opinion on the matter of bed liner on aluminum boats from just what I know of aluminum (AL) in my experience of restoring 3 boats and reading many, many threads here and elsewhere. Others may have differing opinions and observations.
It's all about surface prep when applying anything to aluminum, nothing really wants to stick to it, even the 2 part epoxy like Gluvit or JB weld. The Gluvit adheres well to a clean surface that has been made free of all contaminants and roughed up some with a wire wheel. If anything is applied to aluminum without following the rules then it looses adhesion sooner or later. The Gluvit is only applied to the seams and if you feel the need, rivets 'in the field' between the ribs. When the entire interior hull of the boat is coated with bed liner even if there's proper surface prep there's a huge potential for future issues.
Most times when someone applies bed liner it's because they think it's the easy route to go and take short cuts. If the rubberized bed liner looses adhesion in just one tiny spot, water will get under it, have no way to dry out and become acrid rapidly which begins the process of electrolysis eating away at the the AL creating at best some pitting, at worst holes clear through the hull. I think if the bed liner is applied to a properly prepped surface over SE primer or a factory paint job that's prepped you would have the best adhesion possible for the material but on bare AL it may fail rapidly.
From the Raptor 2 part urethane description...
"[FONT="]U-Pol Raptor Bed Liner Kit Black is a 2-component urethane system designed for application directly to most original manufacturers' paint finishes or any self-etching primer surface."[/FONT]
If you followed this and did not apply the liner to bare AL then your chances of success are greater.
Another reason is that removing the bed liner stuff is an absolute nightmare. Ask
jbcurt00 about his run in with bed liner in a boat.
