Trunk Floor - Final Fit and Weld

The Legend of the Trunk Floor continues...I hear you all catching your breath in anticipation!!

Here's the replacement floor to fill that almighty hole. You can see I've drilled the holes in the floor for the plug-welds and cleaned up the metal where the welds will be (around the holes and along the top edge of the pan). This is a view of the bottom of the floor. As part of it will be inaccessible once welded in, it needs to be rust-proofed now. So I've used epoxy primer which doesn't need a top coat to make it waterproof and hence, rustproof (whatever that means!).

 Here's a pic of the top of the pan, which I can paint later. You can see more holes for plug welding to the main car body.

 More holes!!!..and the areas that will fit against the car body are coated with weld-through primer. (Basically this is a spray metal primer with copper particles in it. These allow the electric arc to pass through the primer when welding - but it also helps prevent rust in areas that are inaccessible after welding in place).

 Now, despite being as precise and careful as I could, I made a bit of a mistake when fitting the floor the first time and had to back-track to correct. Basically, at one point, I'd made the gap between the new floor pan and the car too large, so I had to fill-in with sheet - cut and curved to fit. Here's what I mean..

Below you can see the new pan fits much better now..nice and snug. I was looking for no more than a 1.0mm gap. Mostly the pan sits tightly against the car..see later pics!!

For whatever reason I couldn't get the floor to sit flat at these corners so I had to weld-in small spacers. I wonder if the pressing of the pan at these points is difficult to do at manufacture, as it's less crisp and precise than other folds in the pan. Generally the fit is really good. Here's a weld-primed spacer at one end anyway..

The floor is dropped in and carefully and accurately positioned. To get a really precise fit, you need to hammer here and there to get things flat and to line-up but it's simple enough. Here's some pics of the plug and tack welds to hold the floor in place...

Now the final welds to connect the tack welds. I moved from one side to the next along the top seam and did lengths of roughly 40mm at a time so I didn't create too much heat..

Here it is fully welded in place...

Next it needed to be ground smooth and primed. I stupidly forgot to take a pic of the plug welds along the back edge before I painted with primer. At this stage I ground down the welds and cleaned with a wire-brush on the angle grinder. Then I brushed-on Epoxy Primer nice and thickly onto and into the rear seam...

Here's a pic showing the main seam weld once it was ground smooth. It will ultimately be hidden under a re-inforcement plate so I intentionally didn't grind too far, so as not to thin-out the metal too much. It's already quite thin on the 'car side' from previous rust..

For now, I have just Epoxy primed the rear seam both on the top of the pan and beneath. Ultimately, I will apply plenty of seam sealer over this primer to protect from rust more fully. This is how the floor was finished at the factory.. I hope it lasts longer than it did originally! Here are more pics of the finished, primed seam on top of and under the pan.

I temporarily sprayed any other exposed metal with cheapo primer until I get to spraying it properly with the good stuff!..out.