Looking at pictures showing the breakdown of standard window parts, I think I have the term right. What I want to know is how to properly seal the spot at the bottom where the jamb meets the sill. There is a small slit where the vertical jamb and the horizontal sill meet and I want to be sure that any water in the sill cannot seep into those spots and into the wall cavity. I have caulked those corners on either side, but the caulk gets quite dirty and when opening the window a bunch, the caulk can come loose. Rather than go through and pull out that caulk every year and re-do it, I wanted to get some opinions as to whether there might be a more permanent solution that wouldn't require me to redo that every year.
I'm envisioning something like a solder that can seal the metal slit permanently, would be black or dark in color so it wouldn't show dirt and could be precisely painted on or something so that it could be easily applied and not make a mess. In that way it would be sealed, I could just wipe the inside of the window sill each year and make sure nothing is blocking the majority of the water from getting out of the sill through the exterior facing sill openings and be good to go for another year.
Does that make sense? I attached two pictures to try and make it a bit more clear. Thanks ahead of time for any info/suggestions.