Floor Pan Steel Thickness

[rustomatic]

Okay, folks. I'm nearly done with re-creating the middle (and ends) of my Falcon, and I need a bit of advice on sheetmetal (since I finally quit law school, I'll have so much more time now). I will be adding a bit more tubing to both the tunnel area (to add torsion-fighting structure) and the floor, along with cross bracing at seat and foot areas. (The current cage structure is coming out.)

I was thinking 16 gauge, but now I'm leaning more toward 18, since there will be so much structure underneath. I'll probably definitely use 16 for the front and rear firewalls, but for the floor, it seems a bit much.

I'll happily accept any suggestions here.

[DBasher]

Just to be clear, I don't know anything...but think 18ga with some beads for strength would be just fine. Do you have a bead roller? If not I'll find and post a cool how to.

Congratulations on realizing that your money/time is better spent on the car! I learned everything I need to know about the judicial system at the last Barnum and Bailey show I attended.

[Build-It-Break-it]

I think 18 gauge for all the sheet metal will be plenty. 16 gauge for firewall will be overkill.

[GregWeld]

If it's a track car - and the floor pans have nothing to do with structure... then I'd make them with a thin gauge and bead roll or otherwise build them with some structure so they don't just oil can etc. Why add weight...

Depending on your skills - and equipment - you can make smaller panels as service panels which will also add some structure to them.

I have an air driven flanging tool - that a guy can simply run around the edge of the panel - and the adjacent panel can get flanged in the opposite direction if you want that look or just bead roll it and lay it flat etc ... and you'd be amazed at how much something like this can stiffen the panel.

[rustomatic]

Thanks for the replies, guys! When still struggling with the moving driveshaft situation, I built a raised section of tranny tunnel with 16 gauge, and it was super-sturdy (yet never high enough). With that in mind, it would definitely seem to be a bit of dead weight for many square feet. I'll do some shopping for thinner steel next week.

As for bead rolling, I wasn't really intending to pick up or attempt that skill (or tool), as I'm intending to make many small panels that will be welded to the tubing. In theory, this will lead to less waste (more wire, of course) and fewer stupid errors, along with both potential accessibility and maybe a bit more strength (as mentioned above).

With the tool idea in mind, I'm open to any ghetto sheet bending/rolling tricks anyone has, in case I do try for a longer/wider/contoured panel at one point or another. I love seeing the old-school fab tricks (now occurring to me that I actually have much more time for YouTube, with the loss of my aforementioned terrible hobby).

I will not have a car going by USCA time . . .

[rustomatic]

Thanks for the tip! Do you think 18 is more normal for a firewall? I know this seems like kind of a dumb place to be asking these questions (the info is out there somewhere), but the standards don't seem to be shared with specifics all that often . . .

Originally Posted by Build-It-Break-it

I think 18 gauge for all the sheet metal will be plenty. 16 gauge for firewall will be overkill.

[Build-It-Break-it]

I don't think your question is dumb at all. Sometimes a topic should be brought up for safety or otherwise.

I personally do think 18 gauge is standard for most panels on the car if using mild steel. The only place that might need reinforcing is the brake pedal area but even then in most cases there's a bracket that mounts from the firewall back to the lower steering column adding the strength.

[rustomatic]

Thanks for the tip, Ahmad--I'll probably be doing a floor-mount brake pedal (no clutch for this version of the car), so extra firewall strength will not be an issue (especially with a tube frame behind it). Must think of places to save weight . . .