Got a little bit of a start. Tubs came in on Friday. As I expected, they were arched-type wheel tubs, with significant assembly required. These are 40” 24-guage steel. Pretty thin, but I will reinforce them. Worked a little Saturday afternoon and some today. It more of a pain than I had hoped, as is the usual case.
So I decided just how far back I was going to cut into the cab floor. I need to cut farther towards the middle of the “bed”, as my tires were rubbing the backside of the stock wheel tubs (the vertical part of the inner wheel well). I used a thin piece of aluminum strip, bent to fit the stepped B2 tub, as a straightedge by first clamping then temporally riveting. I am bad at cutting straight with the sawzall, so I need all the help I can get.
Then, using mild steel, I built a frame/lip around the entire cut-out section of the floor. The lip is to A) help reinforce the cut floor, B) provide a straight edge to affix the wheel tub metal to cleanly with mounting points, and C) reduce the amount of welding to sheet-metal or existing tub floor (i.e. allow riveting of the assembly to the floor). I did some experimentation with thin sheetmetal Saturday night with my POS 4-setting MIG welder, and was having a hard time, often burning through even with 0.023” wire. I am by no means a decent welder, especially with the real thin stuff. But then I ran out of CO2/argon mix, so I had to switch to 0.035” flux core, which was even worse. So I decided to weld together a frame, then rivet to the frame. I will still plug weld to the outer wall to eliminate rivets through the quarter panel. (when I get to that).
As the B2 tub has numerous small ridges and valleys, so building the frame was a mild PITA. The steel lip protrudes about 1/8” beyond the cut floor, so I could weld mounting tabs for the inner wheel tub wall. The key is keeping this lip straight. I checked often with a long piece of angle as a straightedge.
I then welded mounting tabs to the lip. Where the floor was flimsy due to cutting existing floor structure, I welded a small long strip of steel perpendicular to the lip (making “angle-iron”, basically). This stiffened everything up nicely.
I very carefully (again, running flux core today) tacked the back wall of the tub, cut to fit my frame, to the frame then riveted the it the various mounting tabs I made.
That’s where I left it today. Next time I might think a little bit more before I start cutting away all ad-hoc like. I am confident, given enough man-hours, I will eventually have them looking OK, but this kind of work isn’t my bag.