I am installing the post war 'D' window channels in my 1941 Cub, and received the new ones from Univair. They are made of very thin steel, a little too thin to be comfortable in using my Tig welder on. It looks like the best way to attach them is to braze them on. I noticed that many of the stringer attachments were brazed on. If any one out there has installed these and has any advise on how did they attach, or know how Piper did it, I would appreciate any info.