(Re)engineering a floor

 A couple weeks ago I shared the removal of the floor pans.  Last weekend (with my sisters approval :) ) I decided to go to Lowes and buy myself a MIG welder.  It's another $380 towards the project, but everyone should have a welder anyway, right? The floor design is pretty straightforward, just a stamped piece of sheet metal.  I don't understand the cowl design Chevy came up with; I'd like to think it was a crush panel they designed, but I doubt in 1965 safety was a major concern. More likely there was something about the manufacturing that created the cowl structure. I can't capture it in the pictures, but there are several layers of steel here.  There is one outer layer, that the rocker is spot welded to.  Inside there is a second layer that forms the inner skin, where you see the large cutout for the vent.  Between the vent and the door is a thick piece of 16 gauge steel, the sets over this layer, and runs down to the base of the rocker.  If you follow the inner rocker from right to left, you can see a line where it goes from gray to rusty.  This is the edge of the inner rocker and the rusty part is part of the thick steel that fills the kick panel by the door. On both sides, this piece held water between the inner and out layers, and cause it to rust through.  There is another layer you can see in the second picture, where the filler panel at the back of the fender rolls around into the rocker.

 Layered sheets of steel are bad when it comes to rust.  Maybe good for safety? I don't know, but my decision was to eliminate this mess, and create one solid piece welded around the edges for the floor to mount to. This eliminates a lot of ugly mess created by the factory design.  It won't be stock, but I think it will look better and function well.  I was surprised to see that in the rockers behind this area, there was no rust at all.  It was just confined to the kick panel area.

There are no replacement panels or guidebook how to fix the kick panel area, so this is where engineering meets trial and error.  After searching at three Lowes stores, I found a piece of 16 gauge steel.  This is about as heavy as one can work by hand.  The original floors are probably 18 or 20 gauge, my guess is the new floors are only 22 gauge or thereabouts.  I wanted the kick panels to use as thick of a piece as I could work to replace all of the thickness from the factory.  My method was to use a piece of posterboard to figure out the shape I wanted, and cut that out.  This is what I came up with, the drivers side is the larger piece, as that side had more rust.

I think this picture gives you an idea what I had to remove.  Lots of rusted pieces and spot welds in this area; using the air hammer really did a number on my wrists.  I'm getting to old for the hard work!  The fender mounting bolt was rusted completely away, so I cut out a body mount bolt from the trunk pan that won't be needed, and welded it in here.  It's a little larger bolt size, but has the correct cage nut to allow the body shop to mount the fender. I found several pieces of windshield and side window class, as well as a mouse nest deep inside the rocker.  The glass had probably been rattling around in there since 1965.  I did leave a broken drill bit behind for the next person to find. A little wire brushing and rust reforming paint, and we're ready for new metal.

Here is what it looks like after welding in the new piece.  What you don't see is the hours of fitting the parts.  Posterboard is much easier to bend than steel, so even though the shape was close, there is a lot of pounding and bending to get the new kick panel in place.  The edges were all welded solid, with a few spot welds in the center for good measure.  Both sides now have a single thick plate that connects from the firewall to rocker to the floor.

Here are a couple pictures of the drivers side.  The rust was worse here, but that almost made the job easier.  I cut out more metal, so had more chances to make the piece fit better.  On the passenger side I was trying to save more of the original metal, which creates more work.

This picture is from underneath showing the drivers side repair of the rocker area.  Originally the filler panel seen at the right would wrap around the kick panel filler. Because this was rusted away, I flipped it and the kick panel repair now wraps around the fender filler panel. I get the strength necessary this way, and it will all be hidden behind the fender.

 After wire brushing the floor, I found one pinhole and some rust under the rear seat that I didn't like the look of.  I cut a patch from the 16 gauge leftover steel and welded it in.  Here it is before cleaning up the welds.  It's been 15 years since I welded, and I need some practice getting back to it.  It's pretty cool to be able to melt two sheets of steel together.

 Dave (son-in-law of Jill's coworker) worked this week to fit the floorpans.  This the part that takes real skill to fit, pound, and otherwise massage the part into place. One challenge he faced is after I cut out and replaced the factory mess that was the kick panel, there was less thickness in that area, so the floorpan needed to be adjusted to fit the larger gap created.  It took a few hours, but he did a great job.  The floorpan will be welded around the edges, and the welds ground flat. Once this is painted and under the carpet, you will never notice.