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R like, as long as they are solid. Most of
the welds in this project were done by
Jason, who has welded before, but not
often. You will need a few tools to
perform this project, including a welder
(flux-core or gas-shielded MIG
preferred), grinder, cut-off wheel, spot-
weld cutter or air-hammer with spot-
weld breaker, small body hammer, drill
and bits, clamps, and a plasma torch (if1 .Our car came with bare floors, so we
could see the bulk of the damage. This
piece of tin had been screwed and glued in
place with silicone. We removed the screws
and pulled it up.1
2. Underneath, we found a nasty mess
of rust. This is a crucial area for chassis
strength—a piece of tin and some screws
will not suffice.2
3. The new pan from Summit Racing was
laid in the car and adjusted for position.
Once adjusted, the perimeter was marked
with a few hash marks. This allows us to
remove all of the locating features of the
original pan and still be able to position the
new floor where it needs to go.3
4. To speed up the process, we used a
Miller Spectrum 375 X-Treme plasma torch
to cut away the old floor. This can also be
done with a cut-off wheel, but it takes a lot
longer.4
5. Where the floor is attached to the
subframe, we used a spot-weld ripper on an
air hammer. You can always cut these with
a special spot-weld cutting drill bit, but the
rust damage makes it really hard to find the
welds, and this is much faster.5
6. Once all the cutting is done, the edges
of the remaining floor were cleaned up with
a flap disc on a grinder. Flap discs remove
material quickly without the heat buildup
of a traditional grinding disc. This disc is
40-grit. The goal is to get a clean, rust-free
surface for welding.6
7. Next, all of the edges were painted with
weld-through coating. Now is a great time
to treat any hidden rust—for example,
inside the subframe—as this is the only
chance you’ll get.7
8. We marked the shape of the subframe on
the new floorpan with a marker and drilled
a series of^3 ⁄ 8 -inch holes, which will become
the new spot-welds.8
possible). You don’t have to use a
plasma cutter, but it really speeds up
the process if you have access to one.
Otherwise, you can use a cut-off wheel.
Before anything gets cut, you must
check the fit of your patch panel. You
must fit the patch before cutting any-
thing—this is critical to a proper repair.
We are using the entire panel, so we
simply placed the pan in the car,
marked the perimeter with a marker,
and made some alignment marks. The
alignment can shift after the old floor
is removed, so having the correct
placement marked on both the pan
and the original floor is important for a
good fit. We used the plasma cutter to
remove the old floor, leaving a^1 ⁄ 4 -inch
lip around the perimeter where the
new pan will rest. This is a lap joint,42 CAR CRAFT OCTOBER 2019