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Why Not A One-Piece Rear Window Corner Patch For All?

posted Sep 5, 2017, 5:12 AM by Dane Belden   [ updated Sep 5, 2017, 5:13 AM ]

We get asked the question “Do you make a one-piece corner and window channel patch?” on a pretty regular basis. It’s a very reasonable question and there is a simple explanation as to why we do not provide one as a standard do-it-yourself patch. It has to do with the manufacturing process employed back in the 1960’s and 1970’s. 

While the cars all appear very similar to each other, there were “liberal” manufacturing tolerances that when you go forward 40-some years to place a patch into a body panel making things fit can prove to be a challenge. The main focus for the installation of a one-piece corner/channel is the window channel depth dimension. 

Because the patch will be plug welded to the existing B-Pillar structure, the height of the channel is critical. We have found this dimension to vary as much as .040” from car-to-car. So, if we provided a one-piece patch with a fixed channel height of say .750”, but the car receiving the patch has a height of .720”, then our one-piece patch will sit high from the surrounding metal by .030” and that is a problem. If the dimensions were reversed then the newly-installed patch would sit low by .030” and then you could make that up with filler, but why do that? 

So our method allows for as much as .1875” of variation and you can still have the corner patch match the surrounding sheet metal. Yes, there is an extra step of butt-welding the seam, but our design hides that under the stainless trim once it’s on, so that amount of bodywork after installation can be minimized. As you see in the pictures attached, we do make one-piece corners from time to time for cars we work on, but to provide a solution to the restoration market in general it’s just not the most practical way. Now you know the rest of the story!