I'm preparing to patch in a short preformed metal patch panel at the front cab corner and cowl on my 53 F-100. From the various illustrations in the catalogs from vendors of these body patch pieces, I see where bent surfaces of the new patch piece get welded on to the existing intact sheet metal parts of the cab. What puzzles me is: what is used to close the back side of this patch panel? I see that full-legnth rocker panels repacements have the necessary material to function as the back side of the corner. On my truck, the rocker panel (which doesn't seem to be a separate piece at all, but rather part of the cab floor sheet metal) is rusted so that there is no material to close the back of the cab corner. I don't want to purchase rocker panels just so I can cut and use the forward-most four inches. I guess I will have to bend some sheet metal to close the cab corner front, but before I do, I wanted to see if anyone has dealt with this issue in a way that I haven't considered.
jvmcc

 

I'm in the process of doing this now Mine was rusted out as well. my biggest problem I ran into was where the cab support meets the floor I didnt want to replece the whole floor board so I did the best I could in fabbing one up since no replacement could be found . A vice wil probly help you out in yoursbends its not that diffucult and no one will ever see it if its off a bit. check out 1955 f-100 on facebook

 

I'm not sure from your description, but here's what I did:
1956 Ford F100 4x2 - Cab Cowl Patch

 

looks like you did a good job.

 

Have you already purchased the cowl corner? Mid Fifties has a new item in this years catalog. It is the cowl corner patch with the front part of the rocker panel made with it. I just saw it AFTER I bought both the cowl corner and rocker panel. I just needed the first 4 inches or so of the rocker panel. I cut the rocker out at the 90 degree bend and the new panel lapped over perfect. Hope this helps.

 

Make sure you line up the patch [gap and curvature ] with your door and fender. Im redoing mine now on curvature to match.