Once the inner fender is rejoined with the body and the weld is ground down, you will need to use a body seam sealer to keep water out of the Jeep. We got this saBesto sprayable seam sealer from Wurth at a trusted body shop and it's awesome. We mentioned that we were doing this project and that we wanted something better than the stuff we'd used last time. The saBesto is easily spreadable and takes paint well. The stuff we'd used last time was a lot like regular silicone, whereas this stuff is just like the seam sealer the factory uses.