Rain Gutter Sealing

Here is how I did this one. First use a heat gun to soften the old seam sealer. Once you get a piece started you just pull with light pressure while heating and most of it will come out, even out of the nooks. Next I used a wire wheel on the grinder to get all the remnants out. Next I hit it real good with some 60 grit by hand to get most of the rust and any remaining loose stuff. Then I treated it with Ospho before applying epoxy primer. I made sure to put excess primer in the trough so it would seep in all the seems. Rags at the ends to catch the runoff. Let it flash then put on a second coat.
So to replace the seam sealer you can use seam sealer like original or you can use a waterproof body filler like "metal 2 metal" or glass reinforced filler. Im using metal 2 metal on this one. Stay away from USC all metal filler, its not very good.
When applying the filler keep in mind if your car has drip edge moldings or not. If so you need to keep the filler/seam sealer down off that vertical lip that the trim clips on. If it doesnt you can bring it almost to the top.
I recently found a brand of seam sealer and weld through primer that is really good and a very decent price. I typically only use 3M seam sealer but this stuff is just as easy to work as the 3M. Have to go to garage and look at brand name but I will post back later.