Lovely standard shape rear arch.
make a nice big cut down the centre of the inner rear arch, then cut around the edge on the seam on the rear quarter then cut accross the front and the rear of the inner arch to join the other two cut up.
You will also need to cut the bottom bit of the side of the rear seat back out where it's spot welded to the rear inner arch.
This is what the piece you cut out should look like (note at this point the arch in the quarter panel is the standard shap with the lip removed.
this is what the hole you have left should look like
The piece of inner arch that has been cut out can now be used to mark the outer bodywork for cutting, put the inner arch side against the panelwork and mark it out. I used my finger and the dirt that was on the car.. lol..
Remember this is not a precise line for cutting, it's a rough guide, use some cutter to start cutting the bodywork out (i always use aircraft style snips) cut it slowly and keep looking at it to make sure that you have not started to cut too much out. i use a small piece of box section rest it on the piece of the inner arch thats left and the outer bodywork where your cutting, make sure it sits horizontal, if it goes up you have cut too much out , if it goes down yo need to cut a little more out.
I would strongly recommend that you don't use a grinder (unless you are extremely good with one)
This is a pic of the other side of my car, you can see where i have marked it out around the inner arch piece i cut out.
you can also see where i have cut it smaller than the marked line and gone back and cut it higher (it's easier to cut more out than it is to put it back)
Once thats cut out get your peice of steel that you are going to use for the new arch and roll it untill it's a slightly smaller radius than the newly cut arch, make sure it's wider as you can cut this and trim it down after.
Start by tacking this in the centre of the arch, tack it on the inner arch as well as the outer arch
Keep taking on untill you have got full arch tacked into place all the way round, tack from the centre and work your way to the edges. Keep the tack close together, the quarter panel will distort a bit around the welded area but this can be kept to a minimum if it's tacked close together
Once it's all tacked you can start seam welding it all the way round, once welded you can trim off the excess metal.
One tubbed arch...
Just remember if you are going to slam your car you will need to move the brake line bracket off of the top of the radius arm and peen the inner arch lip over.
