Reply to "GT5 flare installation durability question?"

Lap joints for Skoda's, butt joints for Pantera's.

Lap joints are rust traps. If the overlapping sheet metal is not 100% sealed with seam sealant, the resulting rust will cause the joint to bulge as the steel de-laminates.
Once this starts, there is nothing you can do but cut the whole thing off and do it properly.
Lap joints prevent metal finishing. It is not possible to beat the perfect panel if there is there is a lap joint in the way.

A butt joint is the only way to join body panel. It does take a lot more skill, and probably 10 times longer. If the two edges are not perfectly aligned, you will get thin spots when you polish down welds. This process is a lot easier on an aluminium body because the ally is nearly twice a thick. The weld should look the same on both sides of the panel. After polishing it down on either side I beat the panel into shape. The heat from the welding causes distortion but does not stretch the metal. Stretching either happens in the panel beating process, or there was simply too much metal there to start with. This is soon corrected by shrinking.
I heat a small spot in the area I want to shrink with the gas torch, wait for it to pop up, then quickly beat around it with a body hammer working the metal into the red-hot centre (kind of like squeezing a zit) and then give it one tap in the centre and let it cool.

Comp 2, you're doing a great job of correcting someone else's work on those arches. Make sure you seal it well from the inside.

I wish I could go back to the stage you're at with my car and improve on a few of the things I did. I was 22 at the time and on a steep learning curve. 13 years on I have a lot more experience. If you haven't already done it, I suggest reinforcing the joint around the rear tail lights. This is brazed from the factory so is very difficult to weld. When I redo my paint someday I am going to put a gusset in behind and weld it solid. I will also do the same in the rear deck lid opening where it curves up towards the roof. This will spread the loads over a wider area and hopefully prevent cracking. I am also going to strengthen the windscreen pillar A post where it connects in the front fender. I intend to insert a steel reinforcement about 6" up the pillar, and plug weld it in lots of places and then attach it very solidly to the inner fender/A post area.
I have done about 15000 miles since I finished my car. It didn't take long for the cracks to show around the tail lights, although they are hard to see. I have just noticed a very fine crack in the deck lid opening. This took about 12000 mile to appear. I have not yet got any cracks at base of the A pillar. I think if I drove it on a track a few times these would appear. I lead loaded all of these stress areas and also the B post area. I do not believe in using lead in any area where it is not necessary, like wheel arches.

My mate Kirk Evans reckons the cracks around the rear tail lights are caused by the fact that the rear panel is not supported properly in its lower outer corner (the sharp corner on the outside of the silencer box) He suggests attaching a rod to this area and taking it up to the chassis. I am going to do this also. If you crab that area with your hand, you will see it flexes up and down quite easily.
Please keep the pictures coming. I always enjoy them!

Johnny