Floor replacement--can't make up my mind

[jaybee]

Regarding my 57 Chevy I've made a decision to NOT buy all new floor pans and underfloor crossmembers.  Doing so would make the budget prohibitive, you can't see them under normal circumstances anyway, I'm building the car for me with no immediate plans for resale, and they aren't that complicated since they're mostly flat without a step down over the frame rail as you'd have in a later car.  Yes, I realize that will kill the car in the eyes of those who think a highly modified tri5 must still have stock floor pans, and there are a fair number of those people around.  Big whoop.  

Still, I want to do this in a way that doesn't result in a patchwork of road signs, barn siding, and aluminum stitched together with pop rivets.  Sounds like I have my mind made up...except.  There are significant amounts of the floor that are still sound.  I could keep those parts, fabricating replacement parts where necessary.  This would include parts of the underfloor crossmembers, as they're a common source of rot and mine is no exception.  I don't have the ability to create exact reproductions although I do have access to a brake and other necessary tools.  To do this with good workmanship my thinking is that anything I replace on one side of the car should be replaced with a mirror-image part on the other side.  For the most part that won't result in all that much "extra" work because what's rusted out on one side is mostly rusted out on the other side, for example the partial crossmembers under the point where the toe boards meet the floor boards are shot on both sides.  OR...I could just tear it all out and start fresh.  That will force me to do significantly more fabrication of crossmembers, driveshaft tunnel and the like, and obviously require quite a bit more metal.  But there won't be any head scratchers about how to merge new with old.

So, given my restriction that I will NOT drop $1200 on reproduction parts that won't be seen except from underneath and in some cases not at all, what's likely to produce the best results?  I should mention that I do have access to a brake, shear, and other tools of a professional sheet metal shop during off hours for that facility.

[UGLY OLDS]

Are the underfloor braces & channels available without the floor pans??  If so,maybe just buy them to get the mounting points & structural integrity back into the body & then use sheet to make your own panels.....
On my Kids '37 Dodge we replaced the complete floor front to back except the rear seat riser.. The body actually "channeled" itself from rust...The rear seat riser was the ONLY useable piece ..

Lots of work but cost effective..  Finish the floor with carpeting as usual & if anyone is looking under the car & questions your work,they are in the proper position for you to answer them...

[chimp koose]

I would replace all the floor if it were my job. it will be less trouble to make larger panels that join with each other than to make jigsaw puzzle pieces just to save some original floor. if you make all your own panels you dont have to make them match the ones that arent removed.I would venture to say you would spend more time trying to fit new to old than if you replace it all.the underside will not have a patched look .if you can find the underfloor bracing panels go for it,then you have something to start from.

[jaybee]

Thanks for the feedback.  I think I've been making this more complicated in my mind than it needs to be.  There are two underfloor braces that run the full width of the floor.  One is real solid with rusty ends and one had the ends cut off with a torch before I got the car.  There are 4 partials that go from the inner rockers to the body mounts but don't go all the way across.  They're all shot.  These 6 pieces are almost $1000 plus the cost of the floor pans, inner and outer rockers, I'm $2000 in just to get a stable foundation to start.

My thoughts at this point are to separate the full crossmembers from the old floor, then build new ends for them and new partials.  These bits don't have to look like the old ones, they just have to be the right height so the body rides the right distance off the body mounts.  Same with the inner rockers.  They're a simple piece and by doing this they can be even simpler.  Then the flooring can also be simplified.  The original has to be turned down, out, and back up at the edge to allow the outer rockers to be pinch welded on the assembly line.

[donsrods]

Nothing wrong with the way you are doing it, you aren't shooting for a concours correct restoration.  Obviously, the thing you want to do is make the body very square and level before you do anything.  Assess what was there originally and try to duplicate it with either bent up pieces or rectangular tubing of a similar size.

The flooring itself can simply be bent up 18 gauge steel with some beads rolled in it for rigidity.  If you drill lots of holes through the 18 gauge and spot weld through those holes it will make it very strong.  Use some weld through primer on the places where you can't ever get back to for rustproofing, then do something like POR15 or Ospho on the big areas. Some seam sealer will work great in all the joints.

I did a '57 Chevy truck just like you are doing it years ago, then put a heavy coat or two of rustoleum over it all.  It was still rustfree when I got rid of the truck.

Don

[sirstude]

On my Ods, I built all the channels and the floor sections.  Both because I didn't want to spend the money, but it turned out that all the reproduction stuff only fit the small Olds anyway.  I think it looks just fine and when it is on the hoist, no one has ever mentioned that it does not look correct.  Just take your time.  I had the big pieces bent at the local sheet metal shop and I have one of the HF 2' finger brakes.  I didn't have the bead roller at the time, so hammered some ribs into any pieces that needed them.  Just use a piece of 4x4 with a grove routed into it and a some round bar stock to make the rib.

Doug

[GPster]

You could channel it and make "NEW" everything. GPster

[48builder]

So, given my restriction that I will NOT drop $1200 on reproduction parts that won't be seen except from underneath and in some cases not at all, what's likely to produce the best results?  I should mention that I do have access to a brake, shear, and other tools of a professional sheet metal shop during off hours for that facility.

I thought of this when I read your post. This guy spent a fortune in repro parts, but he is determined to succeed, and maybe there's some info in here you can use.

Walt

http://57rustbucket.com/571.htm

[jaybee]

He's done a fantastic job of documenting his work and trying to do it right.  My floors are actually starting out better than his, I can at least work inside without falling through!  I'll certainly bookmark that site as it illustrates really well how things go together.  To my way of thinking that's a major part of good workmanship--structural soundness.  An example is this http://57rustbucket.com/574.htm brace that ties the A Pillar to the toe boards and the rockers.  Note that this is a piece that literally will never be seen once the car is finished.  He approached this repair by cutting the spot welds and hand fabricating an exact replacement.  I think this could be fixed just as well by cutting away the rusty tail and stubbing on a new one.  That doesn't mean my approach is better than his, just that it's better for me and my car.  Am I making sense?

[enjenjo]

Go for it. If you were doing something strange, like a 48 Pontiac on a Toronado chassis, you would fabricate the floor, what's the difference.

[Carnut]

WOW! I like that 57Rustbucket website, what a valiant project.

Unless you are building a full concours resto, I sure wouldn't be concerned about bending up and welding in replacement metal. Just take time to make sure you are attaching to good structure and keep things straight until you are done.

I welded in my own metal in the floorboards of my brothers 57 Chev Convertible and my conscience never bothered me.

Course I do come from the old school of car modifing of rip it out and weld it back in.