Kind of working on and off on a series of articles showing these details for most years and plants but here are the basics off the top of my head. If something is confusing or your need more explanation please ask
As welcome to the site
1968 General Paint and Sealant process 1- The unibody was assembled, welded, seams soldered, exterior and interior panels primered and some areas sealed. Trunk, interior, wheel well and drip rails were seam sealed. Sound deadener was applied to the rear wheel wells, interior and trunk areas. As a note, the sound deadener applied to the rear wheel well should not end magically at the edge of that panel but if it was applied up to the edge the spray should continue onto the panels above and behind the edge. Sound deadener applied in the wheel well was applied from below the body from a worker in a pit.
2- To the unibody the doors, trunk lid, rear quarter panel extensions installed (spaced rearward by approx 1/4") and the rear valance was hung by the upper screws. All screws were installed. Rear bumper guard brackets were also installed before the rear valance was installed. The exterior body panels were primed with a light grey surfacer/primer.
During this time the unibody rested on a moving dolly with eight mounting points. The body would remain on this dolly for the entire time the car was being installed during the first half of the cars assembly. This resulted in eight bare spots on the bottom of the car and four (two in the interior and two in the trunk area) visible from above. At these spots a soft round circle was visible as well as the galvanized surface of the frame rails from below.
Individual parts such as the hood, fenders and headlight buckets were painted on a separate line while the unibody was painted on another.
3- Epoxy primer sealer with left over exterior color from the day before mixed in giving a number of different tones was typically used at this plant and time period. During this year and plant the final look is of a dark gray to almost black. This was applied using jets mounted below the body dolly and was applied from the firewall rearward to just short of the rear cross member and valance. The engine compartment area and much of the top area of the body received the traditional red oxide
4- Some seams and the seat belt reinforcements are sealed. The quarter or floor drops and the seat belt points were applied with a brush or pushed out of a gun then smeared with a brush or thinner dipped rag It appears from samples only the inner anchor points were sealed in this manner– this step was often overlooked
at Dearborn
5- Interior paint was applied to the inner door surfaces (does not follow the weatherstrip edge all the way around) the A pillars and dash. After this area is dry masks were placed over these surfaces to protect them during the exterior paint process.
6- Exterior color was applied with some over spray flowing onto the undercarriage. The further a part of the pan hung down the more overspray it received. Application of the overspray could be a little or allot but never the whole floor pan. In the rear wheel wells the area received a nice coat of paint in most cases from direct application of exterior color and over spray/nice coat often found its way onto the exposed rear frame rail that are visible from the wheel well. At the front of the car the exterior color often stops somewhere between the rear edge of the shock tower and the mounting holes for the hood hinges leaving the red oxide (with overspray sometimes) inside the shock tower, wheel side)
7- Next the engine compartment paint is applied. All the surfaces visible from standing at the front of the engine compartment were painted black. Paint was allowed to flow onto the strut rod mounts and to surfaces below the engine compartment. The front radiator support was painted black including the front cross member. During this process black paint flowed rearward onto the front surface of the strut rods again. On the wheel well side black would often be applied to the front panel back to about the forward edge of the shock tower.
Note: It may have been at this point that the dash speaker and defroster areas were black out also.
8- Next the pinch weld was blacked out. The outer edge was a soft edge so many painted just back mask the line. The over spray from this application would again cover some of the undercarriage as it would naturally. Again the more part of the pan hung down the more paint/black out it received. The amount of overspray generally would be less the distance that the body color traveled as it was applied with less pressure. At the rear wheel well the black spray can be found on the rear frame rail between the wheel well and rear shackle hole.
9- Once the front fenders were installed the wheel wells were blackout with sound deadener near the end of the cars assembly processes. The sound deadener was applied to the inner fender panels in front and behind the shock tower. Around the front of the firewall section in the wheel well and onto the rear splash shield. At the front the sound deadener was applied typically across the back side of the headlight area of the fender and onto the front splash shield, then over the top of the wheel well (back side of fender). All of this application was done from below (in a pit) the car
