Entry: 2/1/06 - Today I moved to a new section, the suspension pan below the front nose panel I just finished. Here's a shot showing the parts involved and the rotten areas outlined in red:
Since the front torsion bar pivots are anchored to the ends of the box section formed by the front fuel tank support spotwelded to the front suspension pan, structural integrity of this section is critical. I did some exploratory surgery on the box section between the two front torsion bar mounting points. I found some rot but it was limited to the flat portion in the bottom of the channel, where water had pooled over the years. This rot was even more evident once I had stripped the heavy undercoating off the steel and wire-brushed it to see where the sound steel is. I decided to replace this section one side at a time and preserving the original front towing loop which is still very sound steel. I cut out the rotten sheetmetal, first on the passenger side, and made sure there was plenty of overlap into the sound steel higher on the channel walls by using my flanging tool to create a flange that I'll weld a replacement panel into. I made a pattern from the rotten piece I cut out and fabricated a replacement piece from a sheet of 20-gauge steel. You can see the rotten panel and the replacement panel side-by-side below, as well as how the replacement panel looks being held into place using a drift punch. I think I'm going to get another nice clean patch that won't be detected once the Wurth high-build underseal is applied over the repairs.
Entry: 2/2/06 - Today's labors continued on the front pan box section. Final fitting of the passenger side piece went quickly and it was welded into place using a series of hundreds of MIG spot welds sequenced around the panel, closer with each iteration. This technique allows good weld penetration without heating the panel and warping it. Quite tedious work and requiring a bunch of grinding to dress the weld but the result is a very strong weld due to better weld penetration into the overlapped flanges instead of a thin butt weld. Once the passenger side channel was welded-up, I wire-brushed the drivers side down to bare metal, cut-out the rotten section of the bottom of the box channel and made a pattern from it. As you can see from the following photo, I'm well into shaping the replacement panel and should be welding it in within a couple hours of work. Next project will be doing the last bit of collision repair on that lower, front passenger side corner.
Entry: 2/3/06 - This day was spent finishing the driver's side front pan box section repair. After a couple hours of snipping and hammering the replacement panel into a perfect fit (compare today's patch panel photo below with the how it progressed from yesterday's entry), it was welded in and the front side welds dressed. The back side weld is still just tacks and will need to have the final weld and dressing work done there before the external part of this project is complete. The top of the box section, the fuel tank support pressing inside the front trunk, needs to have some rot removed with some replacement sheetmetal fabrication and then the whole panel welded back into place. Then I will address the final details of that front nose clip, that lower front edge of passenger side. Big winds are supposed to hit here tomorrow and Sunday is the SuperBowl... looks like I'm taking the weekend off.
Entry: 2/6/06 - After surviving both a windstorm that knocked-out power and a heartbreaking Superbowl loss by our Seattle Seahawks on TV powered by portable generator, it was nice to get back to work on the 912 today. First job this morning was doing the final weld and dressing of that weld on the inside (trailing) edge of the box channel patch panels on both sides. As you can see in the following picture, they come very close to the original pressing pattern and will be totally undetectable once the "chunky" undercoating is sprayed on them.
Once the external repairs were done, it was time to deal with the small section of rotted metal on the backside of the tow loop reinforcing panel I had welded the patch panels to. I had already attacked the rust by grinding, chipping and wire brushing it to get all the scales removed, then neutralizing the remaining pits with several coats of SEM Rust Seal. Final step was sealing the Rust Seal surface under several thin coats of JB Kwik Weld epoxy to strengthen and seal out any water that might stand on it. The sheetmetal is rock solid on thicker outer layer of the tow loop reinforcing panel so sealing the surface rust on the thinner inside layer seemed like an acceptable method of preserving the original tow loop. Days earlier, I had cut and bent the lip of the fuel tank support panel that forms the top of the box channel back to get access to the inside of the box channel so today I bent it back into position and prepared to patch it. I've started making a pattern for a patch panel to completely replace the rusted front edge of the fuel tank support and need to decide how much of more of the surrounding rusted areas need to be cut out. Other than one small rust-thru area the floor of the front panel, the majority is all healthy metal to spot weld to so this should be a nice clean patch. I should have all the remaining work on the entire nose repair completed by the end of the week.
Entry: 2/7/06 - Spring fever struck today, it was sunny and beautiful and all the storm clean-up work was done so why not bag the 912 project for the day and take "the Mrs." out for a nice long ride in the country in the 911! Returning inspired to bring the 912 back to the level where I have my 911, I attacked a sheet of 20-gauge metal like a man possessed. I finished the paper pattern, traced it onto the blank sheetmetal and after a couple hours with the Bosch jigsaw, hammers, vise and pneumatic air hammer, I had that hunk of tin formed to fill the opening perfectly. Tonight the resulting patch panel sits vise-gripped into place, ready for the next step, grafting each end into the remnants of the original fuel tank support panel. Now I need to figure out if I can somehow configure the tongs on my spotwelder to attach that front flange of the patch panel to the front suspension pan, just like it was originally. The weather is supposed to be back to the normal rainy gray tomorrow so no distractions.
Entry: 2/8/06 - The fuel tank support sits welded in and sporting a coat of a black product called Rust Encapsulator sold by the Eastwood Company (no relation to Clint), and waits for the coat of the Wurth high-build underseal to blend it back into the surrounding undercoat. The decision to use the Rust Encapsulator was intentional, since I was spot-welding a new piece of steel to an original and slightly rust-pocked pan floor. The Rust Encapsulator will seep into the gaps between the spotwelds and seal them from further rust. The top-coat of high-build underseal will insure the 40-year-old rust will sit dormant as long as moisture and oxygen cannot access it. I ended-up doing spotwelds by drilling a hole in the flange on the fuel tank support and filling it with a small, round weld bead that was actually in the floor pan metal. As you can see from the picture of the floor pan from under the car, I got almost perfect, uniform weld penetration across the spot welds... sometimes I even impress myself! :^D.
The fuel tank support patch was the last step in the front suspension box channel repair, so finally on to the last major step in the nose collision repair, grafting the lower passenger-side front panel to the front pan. I'm already well into the repair by having the vertical panel all squared-up with the plumb-line and the spotwelds holding the sheetmetal flap from the old seam ground away and removed. This should be a very quick repair, then on to fun stuff like fabricating new wire loom tabs across the inside front of the trunk!
Entry: 2/9/06 - Up until today, the bottom seam of the nose graft, where the lower, passenger-side's front panel met the floor of the front pan, was not attached. I wasn't sure how much of the front pan could be saved so I just left the seam unwelded until I was sure. Today, much hammer-and-dolly work was required to straighten and flatten the floor of the front pan back to the original form, matching the drivers-side. Material was cut out in some places and added in others to get the various panels back into the correct position. By evening, I had finished all the welding and dressed the outside beads with the goal of making a test-fit of the front bumper to see if the gap between the front pan and the bumper was even and in alignment across the lower edge. As you can see from the photo below, mission accomplished. Just some very hidden cosmetic work remains on the front panel and spare-tire well, then a coat of Wurth high-build underseal and the collision repair phase of this restoration project is finished... on to the rust repair phase!
Entry: 2/11/06 - It was so warm and sunny yesterday I had to take a break from the 912 project and take my WWII jeep out for a long drive. Today it was time to dive in and wrap-up the last of the outside sheetmetal work on the collision damage. The passenger-side lower front panel edge was straightened and a patch panel added and shaped to match the drivers-side. All that remains to the all the outside work on the nose graft is spot-welding the front weatherstrip lip to the front panel, sealing the weld seams with 3M Ultrapro Autobody Sealant, a thin layer of filler over all the welds and grind marks like I did on the latch sill above it and then a thick coat of Wurth high-build underseal will hide all traces of the repairs. On the inside, in the front of the spare tire well a small amount of patch work and weld dressing remains, probably another day's labor, to get it to the point where it's ready for the Wurth underseal there too. Bottom line is there is good, solid metal everywhere that has been repaired so the BONDO detectors won't go off on some future pre-purchase inspection. I'm quite happy with how this repair has turned-out, the quality of which was a decision factor for how much work I was willing to put into the rust repair on the rest of the car. If the collision repair didn't go well, I would have cut my losses and parted-out the car. As it sits now, this I feel that this car is going to be a very solid and road-worthy car, not some patched-up piece of junk. Another old Porsche will be saved from the junkyard!
Entry: 2/15/06 - With the nose repair all but some minor "mop-up" work remaining, it is time to strip down the car and "prospect" for unseen rust. Besides removing all the glass, doors, headliner and sound-proofing insulation in search of pockets of hidden rust, I'm looking at the big picture and deciding how to best approach the replacement of the rotten longitudinal channels and the cabin floor. Overall the car is as it appeared, no surprise rot. Close inspection of the flanges for the floor panel determined that everything is pretty much intact with the only exception of the area just inside the rear torsion bar mounts. The rear torsion bar tube looks to be very sound where it joins the rear panel under the rear seats and only has rot issues under the outside longitudinal panel. I'm thinking that I'll start by cutting out the rear portion of the floor panel first and see what things look like inside the center tunnel and under the front seat mounts. The pinch weld seam on the replacement floor panel where they join the side longitudinal channels is looking to be the "foundation" from where all the other panels will be welded to.
A UPS delivery arrived from AutoGeek.net with my Wurth high-build underseal and I applied a test coat to the fuel tank support panel patch. I think a thin coat of the new underseal over the original stuff will further blend in the repair. It is almost impossible to see where the 2" x 3" patch was made just ahead of the passenger side drain in the spare tire well. You might recognize where it came from when you see the following photo:
I'm kinda motivated to weld in the three wiring harness tabs and give the passenger side cowl a coat of the underseal just to enjoy at least one portion of the car looking finished.
Entry: 2/17/06 - The photo below shows the before and after on the front suspension box channel rust repair after a coat of Wurth high-build underseal:
The final photo below is the finished spare tire well with the new wiring harness tabs installed, the Wurth high-build underseal applied and the wiring harness ("relieved" of the added wiring and antique aftermarket fog light relays) threaded thru the wiring harness tabs. I did some more "prospecting" for rust on the drivers-side longitudinal under the rear torsion bar tube and see the biggest challenge is to figure out how to replace a long section of the heater duct tube that runs inside the longitudinal channel, which is also rusted thru. I'm walking through all the tasks and trying to decide the work sequence and what needs to be braced, and where, when the rocker panels are cut out.