ok so heres how I made the repairs for my rear inner arch. there may be other ways of doing this or quicker ways, but this is what I did and you may or may not find some of the tips useful. In fact it may be worth buying a complete inner arch - wish I had : enjoy ......... having chopped off the outer arch (as there was a few small rust bubbles) I realised I'm going to have to do some repairs to the inner arch Its not too bad but there are a few holes - the black is paint where I had wire brushed off some surface rust to see how much I needed repair, I wanted to protect it again now it was bare metal I'm going to make a repair panel for the inner arch, there is a few ways of making this bit, such as beating a flange around a curved edge .....but I've yet to master that art so I'll show you how Im going to do it. I started off with with a length of 1.2mm steel approx 1.5mr long- I was given this with a lip already bent into it, so although the lip is a couple of mm narrower than I would like Im going to use it because its free. There is a bit of surface rust which I will clean up at the end. This is the off cut so you know what Im talking about next I offered it up to the inner arch making sure it would cover the repair along the top of the arch opening and marked where it would start to bend. I then made some straight cuts down to the lip from where it would start to bend ...like so I then clamped it on top of the inner arch at the furthest end from the bend Im making and gently pushed into the corner, I could then get another clamp just in front of the bend you can see that as the panel is pushed into the bend, the straight cuts I made open out into triangular gaps and allow the metal to be bent into the shape of the arch
Next I got another clamp on just where the bend starts but you can see that the bottom still wants to come in a bit as its sticking out too much so I cut into the lip slightly like so this relieves the tension in the metal enough to ease the bottom in a bit using a wide jaw clamp and by hand without buckling to get the curvature even tighter and closer to the original gently hammer the lip and side of the repair looking much tighter now
plenty of clamps supporting the panel in place are essential, you also dont want them clamping too tight other wise the repair piece will not move when you try to form it to shap - too loose and the repair panel will fall off. Obviously all this cutting has made the repair piece very flexible but very fragile. The more cuts you make the smoother the curve will be but be careful not to weaken it too much at this point. So to firm it all up I tack weld at the end or the slits along the bend, the trick here is to use a low power setting .....blobby welds with poor penetration are perfect here as you dont want to weld the new repair over the top of the rusty bits.....we will be grafting it in that should hold the shape of the bend if I have to take the repair bit off at any time. next I use a large pair of long jaw grips like these I adjust them so they dont clamp the new repair to the original so you have to use your hand to grip the panels together and not the "lock" on the locking grips, and gently work my way over the top bit of the repair where it starts to curve back to start forming it to shape. The key is to gently roll the grips in the direction of the bend and not just clamp them straight down - sort of gently rock the grips so the metal slips a little between the jaws
next I make some little filler bits for all the gaps I find it easier to form the metal before welding in the filler bits although keep adjusting/ hammering the panel as you go thats a few of them welded in. then a few more welded in and trimmed down a little (always make your repairs bigger than you need so you can adjust as you go) unclamped, it now it has its rigidity back, and held next to the original to compare profiles not bad so far - still a little bit of work yet next I will clamp it in place again and do any more tweeks nesecary and weld part of it properly from the rear. I still need to form part of it into the seal channel though so I wont weld it all completly
I clamped it up to the bus and marked a bit more to cut off (still leaving it larger than I need) Then I decided to bend the long straight bit to slope back in. Just having the lip on the bottom at 90 degrees would have meant the inner repair would want to go straight up like the outer panel so this bend was needed. Not sure if you can make it out in the photo you can see the profile getting closer trouble is now I've bent the long bit when I clamp it up the bottom is now out slightly clamping it tight so its in the right place throws the straight bit out holding a straight bit of metal against the long bit you can see that I have curved to repair slightly when putting in the last bend so I put a couple of slits in the lip to bend it straight again and clamped back on the bus.....
after another 3/4 hr of bending and tweeking, bending one bit would throw it off some where else I decided that it was close enough and I would do any more tweeks after I welded it up.......which I did, ground them down and offered it up to the bus again the welding had distorted it slightly so using my long jaw clamps I "rolled" it back to close to the right profile. I meantioned in the last post how I did this, I tighten up the locking clamp so I cant lock it, so I can only use my hand pressure to clamp down. I then start with the jaws 90 degrees to the repair piece like this and then roll it upwards to bend the metal in like this doing this all around the area you want to form next I scribed around my repair peice and removed from the bus so I could see how much I had to play with
Obvoiusly I can only do so much with the rotten bits left on the bus, so next I cut out the rot well within the line I had scribed around the repair piece and removed it carefully as I may have to refer to it as a template ....this is what I took off from here..... and laying over the out side of my repair bit pretty close, but it looks even closed laying on the inside of my repair really please with the shape so far next I clamped the repair back on the bus ....you can see that now I have removed some of the rot, the repair sits slightly differently against the bus..... when I was happy it was in the right place I scribed the back of the repair along the lines of the rot I had cut off. removed repair from bus and cut just out side the lines, offered it up again to check, cut a little more off until I've got this... you can just about see that the panel is just about cut to size, its actually still a little big as it is still clamped over the old panel at either end as can bee seen when I lay it against the bit I cut off
I bent over part of the repair piece to lead into the foam seal chanel - not sure if you can see it very well in the pic....I cut most of it off in the end. Of course bending again twisted my repair panel so I had to make a few more slits to bend it back at this point I decide to weld up the slits to stop it moving again but before I do I check against the old bit I removed offering it up again to the bus and groping behind to mark for the next cut......at this point Id like to remind you that after cutting metal its a good idea to get rid of the sharp edges!!! I cut my finger tips several times. once cut I clamped back on the bus to check how it fits At this point I only take off a tiny amount at a time as each time I remove a bit and offer it up it sits slightly differently until you get it right all the way around pretty happy with the fit now so off it comes for some wire brushing to get rid of any rust finally I can tack weld it on then weld properly just got to finish of the last little bit at the end then tidy it all up
just had the little bit at the bottom to finish off so I made a slit here and here so I could bend it in and get that funny little point like the original then weld up the cuts and grind down to shape then cleaned up, a little more tweeking then a coat of epoxy mastic..... thats pretty close to original I'd say ....phew hope you enjoyed it or got some use out of it
It ended up ok chap, but the thread would be better titled "How Not to...". Not meant to be offensive but you know what I mean - you lived it!
thanks guys .....I do know what you mean zed ;D just thought some of the methods might be useful for any one starting out, but your right, there are easier ways like buying another panel ;D
Great thread I have the rear inner to repair this week. still not made mind up about fabbing up from sheet metal or cutting piece from another outer panel to get the shape. Its a shame there isnt a repair panel for this as its a common rot spot. dont want to have to buy a whole tub.
I did similar thing doing my home resto. Then when I started charging people, I had to become way more efficient. There are certain panels when you start, you don't even think of as one piece, and they can seem daunting to replace - rear tubs are a good example. Don't get me wrong - everything still takes far longer than I'd like.
