With the 3-day Labor Day weekend, it was a good chance to tackle the biggest single fabrication job of the whole project - the lower rear rack. This is the rack which is sunk below the floor of the rear compartment. After some thought, I decided to go with 8 batteries in this rack instead of 9 - it yields a symmetrical design - which means that many parts are mirror images of another part, which makes it much easier to fabricate. Here are the plans, done in Google Sketchup:
Here is a Sketchup-generated picture of the designed rack:
One thing not shown in these plans and pictures is the sheet metal box that will be welded to this rack - I don't want water getting into the passenger compartment.
The first step was to start on the lower portion of the rack. I cut out the 8 pieces, sanded them, and test fit them:
They were then welded together (along with the diagonal supports at the corners). Next, I cut all the uprights - 6 angle brackets at the corners, and 5 pieces of 1 1/2" bar stock in between:
I welded the corner brackets on, then welded the top angle bracket cross-pieces on these. I did this so I could take actual measurements of the corner angle brackets and the rear bar:
After cutting the corner brackets, next step was to sand them all up nice and pretty (and cleaner for better welding). I used a cool flap-wheel sanding disk on my angle grinder - made short work of the rust, grease, and paint that was on the angle stock:
I then welded it all together...
...and ground off the tops of the weld beads where it mattered, and wire brushed the welding flux off of everything else:
Next challenge - the rear compartment. After removing all the carpet, it was clear that a minor rust problem was developing:
So, I used the flap-wheel disk and ground all the rusty spots down. One of the rusty spots actually penetrated - you can see the weld patch near the left rear whell-well and gas tank filler cover. Here it is, primed and ready for...
...cutting! I used a cutoff wheel on my angle grinder for most of the cuts, but some of the cuts were deeper (through non-necessary cross members). For those, it was Sawzall time:
Here is the completed hole. At the top, you can see the cross-members I needed to cut through. These were to support the gas tank, and are not needed for the electrical Jeep. They will provide extra sturdiness for the rear rack, though, so I won't remove them.
And here is the rear rack, dropped in to place! I had to enlarge the hole slightly (it's always easier to enlarge a hole than to make it smaller...) and had to bend up the sheet metal where the hatchback closing trim fits - it will get bent back once everything is mounted for good:
And here are 8 batteries test-fit in the box, all snug and happy:
Next steps for this rack: welding sheet metal around to make it waterproof; POR-15 and UV-resistant topcoat; seam-sealing; and final attachment. I also still need to fabricate the polypropylene top and steel hold-downs. Maybe next weekend... or I might work on the 7-battery upper rear rack next. Decisions, decisions.