Hello everyone I have been doing some body work on my car. Overall the car is pretty solid and has never been driven in the winter. Im not a body work expert but have done enough over the years to keep my vehicles solid. I found some rust under the seam sealer at the point between the the firewall and cowl. I have welded some new metal and applied duraglass on another area close to the cowl right next to the door jamb.
My problem is that I can’t access the area inside the cowl to apply some seam sealer and por15 after I potentially weld new metal in. I’m not looking for showroom results as the car has 220k. Im thinking I could maybe access the area after I remove one of the wiper linkages and fish my hand in there with a camera scope. I just don’t want the cowl to rust any further and not drain water into the car. I’m thinking of just filling the back side of the seam with some homemade cavity wax that I made out of diesel sae30 oil and pariffin wax

Here are some pics of the work I done so far I would greatly appreciate some help, sorry for all pics

 

Hello everyone I went back and took some more pictures. I thinking of leaving the bottom of the patch open where I am pointing with the screwdriver and the water would roll down the wheel well . Also I would duraglass the backside inside the car so no water would get in the car fill the open space with cavity wax where it welds to the cowl well

 

Hello everyone, I have some more pics. I think I rushed in to this patch as I wasn’t visualizing the intricacies of this area. I already put some chassis saver in some spots I will remove it and start over. I also cut the section out as I was struggling to get into this tight area, I will reweld it back and use a mirror to seal the backside. I’m still learning with body work as it was never my specialty.