Monday, 6 November 2017

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...

Monday, 23 October 2017

Two is company

After another few weeks of part-time garage tinkering the other cross member has now undergone its wondrous transformation to make it '65 accurate:

I followed exactly the same process as before, so see my previous post if you would like the recipe and wish to indulge yourself with countless photos of metal fettling. 

I now present the two modified cross members together for the very first time:

A very fine pair indeed. Although they are now complete, the rear reinforcement panels do still need spot welding into place. As I am sure i've mentioned previously; I don't want to commit and attach them together just yet as I'm keen to have a proper test fit with the chassis and rest of the shell before finalising. Just want to ensure that I have some wiggle room if things don't line up right (which I am half expecting things not to!)...

Saturday, 30 September 2017

Modifying the new cross members

As I mentioned in the last post, I now have some new 'German' cross members which I am going to be using as a foundation to produce some year correct ones (i.e: '64 - '66 Beetle). They will not be 100% accurate, but will come pretty damn close. I have given this a lot of thought and it seems like the best approach as mid-sixties cross members simply don't exist as a repro item. Cross members commonly rust out on a vast majority of old bugs, so getting hold of a rot-fee OG section is almost impossible and only exist on rare foreign cars that have been driven exclusively in dry climates. Anyway, I have not seen this particular modification done before, so hopefully this detailed overview will be of some help to others who may be interested in doing the same... 

I began by drilling out the spot welds and separating the reinforcement section from the main panel. This gave me better access and allowed for a neater job:

On the main panel I smoothed out the unnecessary hump by simply cutting around it and welding in flat sheet steel:

These repros include an access hole to the heater channel. This was not something that mid-sixties cross members had, so I welded it up:

The rear edge needed a new profile adding to accommodate the correct upward angle of the heater pipe. After careful measuring and scribbling a few notes I mocked up a cardboard version of the hump I was trying to recreate:

I then transferred the measurements to sheet steel and cut out the geometric net:

After some folding on the vice and a quick zap of the MIG welder to close up the slits:

Linished back and compared to the original:

tacked into place on the cross member once the appropriate recess was measured and cut out:

After being fully welded, tweaked and dressed:

Just after the hump is a small section that is bent down on the original. I had to improvise around this section as access for clamping was tight. After some careful tapping with the hammer (remember that man light taps are better than fewer hard bashes), I got the 90 degree bend I was after:

Next task was to alter the heater pipe hole to the correct oval shape:

And trim the return flange to match the original (which terminates about halfway down):

At this point I roughly bolted up the heater channels to the pan and added the crossmembers. The fit wasn't as good as I had hoped and I was unsure at this stage if this was due to the restored pan being off or it the location of the mounting holes in the new panel were incorrect. After some head-scratching I discovered that the lower holes were not spaced apart close enough. There was a 5mm difference compared to the OG spacing. 

To correct this I elongated the hole;

Then using a copper backer I welded the other end to close up the gap slightly:

After some Dremel tool action I had it all looking correct again:

I then shot blast the entire panel before plug welded the mounting reinforcement sections back into place:

Moving on to the thicker supporting rear panel that I removed in the first step, I proceeded to cut out the unnecessary hump and chopped off the rear section that I assume adds strength to the underside of the boot corners. However, this was not present on the originals so I determined that it was surplus to requirements:

Welded in some flat sheet to replace that bump and welded up the access hole that was also present on the main section:

I welded up this little join to add a bit more rigidity:

Shaped the mating flange that will eventually fix to the inner side of the rear wheel arch:

Shot blast the reinforcement panel and got it realigned the best I could to the main section. I decided not to plug weld the pieces together at this point, just in case I needed to adjust anything further down the road. So, here is the nearly finished article just prior to spraying with zinc primer:

Now to do the same on the other side...

Friday, 8 September 2017

Rethinking the rear crossmembers

Although I had previously acquired a pair of genuine VW rear crossmembers I have since decided to take another route. Those Mexi ones could be made to work but have a different overall profile to the mid-sixties ones and are more square/angular looking. They also lack the mounting stud that locates the bottom hole of the rear wing as they are designed for later cars. One other annoyance is that they don't fit up to the Klassic Fab heater channels without trimming down the mating flange (located at the and of the channel) considerably. Those channels were expensive because they are high quality and accurate; I really don't fancy chopping them about!

Fortuitously a new reproduction crossmember has recently appeared on the market from out of nowhere and is supposedly 'German' quality (always a bit sceptical about that term) and made from factory gauge steel. I have seen them being used in a couple of other restorations, but have been unable to find out a lot of information about them. So, I contacted VW Heritage (one of the only UK stockists) to see if they had more about the manufacturer and swiftly received the following reply; "We don't have the manufacturers name, but we source them from a German supplier". Oh well, despite being no clearer about their origins I took the plunge and ordered a pair. I knew that they would still need modifying as they are made for cars up to '63, but in general they are a lot closer to mid-sixties OG ones and therefore a more logical basis to start from. I was quite impressed when they arrived, thick steel and super crisp pressings. Here is how they visually compare against the genuine Mexi (grey) ones, you can clearly see how much they differ:

I salvaged a few things from my old crossmembers that will be transferred over to the new ones. Firstly, I needed to remove the heater pipe. I shot blast the area so that I could reveal where the factory welds were:

I then carefully worked my way around the pipe (on the front and backside) with the Dremel tool equipped with a small cutting disc until it came free:

Next task was to separate these little reinforcement pieces from the top of the bolt holes using the spot weld cutter:

After a quick clean up they are ready to be reused:

Utilising the remains of the old crossmembers as reference I am able to study what I need to do in order to make the new panels close to OG and devise a plan of action. In the next post I will go into detail about how to adapt the new cross members to make them correct for a '64 - '66 Beetle...