Bulkhead repairs with Mexi steel

Made another thrifty eBay purchase, which came up for sale right when I needed it (what timing!). It's a genuine VW front firewall / bulkhead / cross panel;

Despite being for a '68 and later car I figured I could use generic sections of it to repair my original. Before cutting it up I couldn't resist a quick layout of my Mexi steel collection:

I must confess that I do get a mild thrill when I acquire these Mexi panels. Although they are not as crisp as original German stamped parts, they are still vastly superior to the usual repro options. Talking about repro alternatives, I did actually purchase a Klokkershite panel a while back as I thought I could rework it with some effort into something half decent. My enthusiasm was quashed when I received the panel and I promptly sent it back for a refund!  It was riddled with defects with the spot welds literally coming away at one of the seams. The two sections of the panel were clearly misaligned. Additionally, it was apparent that it had been returned before by someone else as there were pencil marks on it as well as a lot of scuff marks & scratches to the transit paint. I was glad to see the back of it;

Back to the Mexi panel and I carefully drilled out a bunch of spot welds and separated the inner section from the main panel. They were pretty beefy spot welds and I had to drill out to 6mm to get them loose:

Note the small patches of rust already getting a foothold in between the seams - it goes to show that just because the panel is NOS doesn't mean it is corrosion free! I figured I would start with the inner footwell section first as it is thicker steel than the main panel (which is a mere 0.7mm) and therefore easier to weld. I think subconsciously I was after an quick win to boost my confidence before embarking upon something I knew would be tricky. Anyway, I blasted my original so I could make an assessment of its true condition:

Believe me, it was even worse than it looks in those pics. Quite a lot of pin holes and thinned areas of steel along the bottom flange where water had got inside and worked its corrosive magic. I marked up some cut lines and trimmed off the bad sections:

It was then a case of marking up the corresponding sections of the Mexi panel and chopping those out accordingly. I cut them a little bit oversize so that I could finely trim and file to the perfect fit:

Once trimmed up I blasted the donor sections. Here is a comparison between the old and the new. This illustrates just how much of my original had rotted away on the bottom corners:

After a lot of trail fitting, more trimming and rechecking I had the repair sections prepped and ready to weld:

welded, linished and finished (note that I also welded up those unneeded holes):

I did not smooth the welds on the rear side as this wont be visible and will add a little extra strength to the repaired areas. So, that's it for the front panel and I am fairly pleased with how it turned out. 

Still debating the best approach for the main panel, but have a few ideas that are percolating in the back of my mind and work will commence shortly...