Thread: C5 gto
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Old 08-04-2017, 09:57 PM
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heinke heinke is offline
MetalShaper of the Month Jan 2018
 
Join Date: Nov 2009
Location: Livermore, CA
Posts: 381
Post Making GTO trunk lid (cont.)

The GTO trunk lid is now complete. I got it 90% complete and then had to step away for a few days to help at Boy Scout camp for my sonís troop. Iím back, recuperated and finished up the trunk lid.

Hereís the detail. First, let me give some context. This trunk skin is a very low crown panel. I already talked about the challenges in shaping the skin to achieve this crown. What I didnít talk about is that there were several things along the way giving me doubt about how well this would end up.

Firstly, as I was annealing the edge prior to flanging, the skin would oil can and loose the crown just from heating an edge section. After the heated section was quenched, a small press on the skin backside would ďpopĒ the crown back in place. While I understand the physics at play, having a piece of metal continually pop out of shape doesnít instill confidence.

Secondly, while installing the skin, it oil canned many times losing the crown. Again, a small press on the backside and it popped right back in place. I finally set a sandbag on the backside middle to keep the crown from oil canning while I was installing the skin. Again, the fact I needed to do this did not instill confidence.

Hammering the flange over to close the hem was mostly straightforward. I started in the middle of the long sides and worked out to the corners so I wouldnít trap any metal. The inward curved section that goes around the fuel opening was different though. I couldnít just flange it to 90 degrees, anneal, and then close the hem. It would have required a big shrink and then re-stretch to do it that way given the inward curve in this section. I decided to do it in a continuous/flowing roll to keep the arrangement as close as possible.





Then the hem was closed out at the bottom corners.



The trunk lid fits great and the gap came out nice. I had to do some hammer and dolly work for edge height adjustments but I was able to match the surfaces all around.



The skin came out smooth with the desired crown. Once the trunk latch was installed, the underside latch support bracket prevents the crown from oil canning out. I didnít have a lot of confidence but it seems to have turned out fine in that regards.



I do like how the trunk lid underside turned out as well.



There were some challenges with this one, but allís well that ends well
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