White paintable sealant is part of the finishing materials in my purchase records.
The featured Amazon option is DAP ALEX PLUS White Caulk.
Where it fits my build
I marked the opening beneath the passenger seat and used a drill, reciprocating saw and grinder to make it. I then drilled the mounting holes and sanded the cut area.
The finishing sequence included two coats of primer and two coats of white paint. That put the cutting, abrasive preparation and coating into distinct steps before the heater mounting continued.
The cut heater-opening area during finishing work.White paint around the heater mounting opening after preparation.
My build notes
The opening changed from marked sheet metal to a cut edge and then to a painted mounting area. The sequence in the photos explains the role of the finishing supplies alongside the cutting tools.
Cutting the opening was followed by abrasive preparation and coating before assembly continued.
Alternative products
Two alternatives to compare
DAP ALEX PLUS combines acrylic latex caulk with silicone. ALEX Fast Dry and Sashco Big Stretch provide two other white paintable-caulk options.
DAP Alex Fast Dry White Caulk
This white acrylic-latex caulk comes in a dispensing cartridge. Its nozzle provides a way to lay a bead along trim joints and small gaps.
