Project in progress or the good, the bad, the ugly.
2001-11-15 by Mike Denman
Hi Maniacs, Two new photos (in Mike Denman's project album). The first photo (must be viewed full size to see the detail) shows the rear end with the cracks opened up and ready to repair. The black marks on the left side are cracks that could be seen on the inside but not on the outside. These cracks need to be opened up for repair (from the outside). This is why spider cracks often re-appear after a repair is done. From the outside you can't see them all so some escape repair and become visible later after the repair is done. The 2nd picture is a close up of some of the spider cracks that have been opened up for repair. I used a ¼ carbide tulip shaped bit in a high-speed grinder to open the cracks up. The cracks need to be completely ground away and the resulting groove should be at least a ¼ wide at the top and tapering to the bottom. Since I have added two additional layers of fiberglass on the inside, this is easy to do. When you are doing the repair on a panel where the backside is not accessible, it is more difficult since you don't want to grind a groove all the way through the panel. Although I could begin the filling process at this time, I will deviate from the normal repair process at this point. If you look at one of the rear end photos that shows the entire rear end you will notice that most of the spider cracks are in groups. The opening up of the cracks has created little islands of undisturbed fiberglass. Since I want to "re-contour" this rear panel to make it really flat I will need to add some fiberglass over most of the outside of the rear panel. So, rather than leave the cracks as they appear now, I will take a 2 inch sanding disk (36 grit) in an angle grinder and blend all the grooves together that are close to each other. This will result in several large repair sites instead of many small repair sites and less opportunity for the cracks to reappear. On a panel with a lot of detail that would be a bad idea since it would be easy to lose the contour or detail. This rear panel is flat (or will be when I get through) so that is not an issue. More photo's tomorrow. Mike Denman 1966 Marcos 1800 Chassis # 4079