First Generation Firebird-L Mailing List ......................................................................... The copper served two purposes. The first is to back up the weld as a heat sink. If you put copper sheet behind the weld, it will help avoid burning through. The weld won't stick to the copper. The copper acts as a heat sink to draw some excess heat away. This way you can get full penetration of the weld without burning through. The weld is much flatter on the back side. Full penetration is important because pinholes through the butt weld will let moisture in behind the paint and cause failure.
The second purpose is for something for the cleco clips to grab onto. Clecos grab onto a hole in the panel. With the panel split at the patch, there isn't any hole for the cleco to grab onto. Since the cleco clips have no hole to latch onto, the holes drilled in the copper serve that purpose. If you can reach the back of the panel, you can use small screws and washers instead of clecos. There are other ways to do this. Some people flange the patch and do an overlaped weld. I think that poses the risk of stress telegraphing through the finish later on as a wrinkle or wave in the reflection. Clecos: http://www.aircraftspruce.com/catalog/topages/sheetholder.php Larry --- On Mon, 3/2/09, Ridell, Niklas (C.N.) <[email protected]> wrote: From: Ridell, Niklas (C.N.) <[email protected]> Subject: RE: [FGF] Rear lower quarter To: "First Generation Firebird-L" <[email protected]> Date: Monday, March 2, 2009, 8:39 AM First Generation Firebird-L Mailing List ......................................................................... Hey Larry, I'm curious about the copper sheet metal you're using. What's the purpose? How do you keep them in position? ...and how do you get them out when done? Please educate me... /Niklas ------------------------------------------------------------------------ Submissions to Firebird-L: <[email protected]> Unsubscribe from Firebird-L: <[email protected]> Help: <http://FirstGenFirebird.org/firebird/Firebird-L.html> Classifieds: <http://FirstGenFirebird.org/ubb/> Owner Pictures: <http://FirstGenFirebird.org/show/> Donations: <http://FirstGenFirebird.org/store/cart.mv?999999> FGF Merchandise: <http://FirstGenFirebird.org/store>
