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 Post subject: floorpan material
PostPosted: January 11, 2008, 3:21 am 
Bringing up an old discussion, this ilistrates the importance of choosing the correct material. http://postworthy.com/Worthy/ex/Jeep_Vs_Tree/60.aspx this brought by USA7s http://www.usa7s.com/aspnetforum/Default.aspx?g=posts&t=1962 I intend on using at least 14 ga for the front of foot boxes and the area under feet and seat with the rest being 16 ga. The small additional weight is a small price to be paid for saftey.


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PostPosted: January 11, 2008, 4:19 am 
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I'll be someone's balls were pretty shrivelled after that one...

But seriously, I would consider the floor pan thickness the least of my concerns. The Seven just isn't made for accidents. After being hit pretty good by a F150 in my Mini, I really don't think I'd be talking today if she had hit me in my Seven. Besides, I don't plan on going offroading in mine, at least not intentionally.

If you really were interested in safety, other things to consider would be full roll cage, sturdy bumpers, and a thick bulkhead in the rear, to start. I accept the fact that if I am hit by a larger vehicle, I probably won't walk away. My only concern for safety is at least moderate safety while on the track. I think the chances of hitting or being hit by another Seven will be ok, being like cars, but any SUV or large vehicle has a one ton advantage at least, usually. It's simply a risk I'm willing to take.

Again, this is coming from someone with no official safety background, but looking at Mark Rivera's crash, I have trust in the Seven's track safety, however, being in several accidents myself, I don't think it would have survived any of them... although it would have been able to avoid several ;)


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PostPosted: January 11, 2008, 11:16 am 
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I think that if you ran into that fallen tree all the floor thickness in the world won't help you - it's at the height of the windshield.

Bank like glass for windsield, anyone?
:wink:

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PostPosted: January 11, 2008, 11:29 am 
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For my floorpan and front footwell I'll be using.032" T304. I believe that's what Kurt used on Kimini. I have a small coil of it here so it's available. My car is going to be a Sunday cruiser and my road racing days are far, far behind me. Having kids will do that to a guy.

I'm more concerned with being rear ended and winding up as a screaming, arm waving fireball.

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PostPosted: January 11, 2008, 11:40 am 
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Do you really expect steel would be better then an equal weight Aluminum panel? Stiffness goes by the cube of thickness...

The rear end of these cars do seem a little week so far as collision protection. A proper built in roll cage perhaps should include a hoop going back around the gas tank...

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PostPosted: January 11, 2008, 11:56 am 
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horizenjob wrote:
Do you really expect steel would be better then an equal weight Aluminium panel? Stiffness goes by the cube of thickness...

The rear end of these cars do seem a little week so far as collision protection. A proper built in roll cage perhaps should include a hoop going back around the gas tank...


To get the same weight as .032 T304 I'd have to go with a .095" thick aluminum sheet. That's awful thick and tough to work with. But the biggest thing for me - the .032 is free.

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PostPosted: January 11, 2008, 12:15 pm 
I'm using .125" aluminum alloy. I'm not sure what alloy it is, but it's anodized, it took 4 hours to cut with a jigsaw, it used up 5 bi-metal blades, burned out a new jigsaw, and it rings like tool steel when you tap it with something. I figure it's a lot stronger than the usual production car's sheet metal steel floor...


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PostPosted: January 11, 2008, 12:47 pm 
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Steel is more heat resistant and less likely to crack and rupture in a crash. Many forms of racing require steel at the engine firewall, the fuel tank firewall, the floor under the driver, or all of the above. Other areas can be aluminum.

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PostPosted: January 12, 2008, 12:35 pm 
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Yes, free can certainly influence the tradeoffs! People on this forum have
so many goals - you can never really address them all.

If your panels are going to help provide stiffness, the thickness of the
aluminum would be very helpful because it won't distort as quickly under
stress ( wrinkle, I suppose ).

Tubs ( Al ) for formula race cars have been made for many years, so I don't
think it's a big safety issue - certainly we've all seen people walk away
from wrecked race cars.

As for cutting, I understand circular saw carbide blades for wood work well
on plate. At least that's what boat building people use. Maybe .125 is too thin
for that. Aluminum can be very hard and a jig saw doesn't use
many teeth, so maybe that's the problem. Carbide should help with that!
Hearing protection would probably be in order...

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PostPosted: December 31, 2008, 9:02 pm 
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Can I ask a question in an old but relevant thread? Are there any problems that could be realistically expected to happen when riveting aluminum to steel? I'm mainly asking about the potential for electrolysis causing mischief with this two metals. If it is a potential enough problem, what could be done to mitigate it? - paint, rubber gasket, bonding compound?

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PostPosted: December 31, 2008, 9:32 pm 
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The aluminum is pretty easy to replace because it's easy to work with. The folks on the UK board have more info on this, because they've been around longer. I think polyurethane is supposed to work well to bond and use with rivets

At least some types of silicone are not recommended and I have heard of some of those products referred to as "rust in a tube". I'm not sure why, I think that the galvanic corrosion eats the aluminum, not the steel. So it may be for another reason, perhaps the ones that generate acetic acid when they cure eat the steel? I have always wondered about that comment.

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PostPosted: January 1, 2009, 12:21 am 
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You guys can always take a two-stage approach. I used very thin stainless on Kimini, but added a second floor panel (attached from inside) under my feet to keep my legs inboard if the floorpan got ripped out. It wasn't so much for intrusion protection that serves that purpose, too.

Image

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PostPosted: January 6, 2009, 2:34 pm 
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I also used a two floor setup for the foot wells. This was prompted by Kurt's scenario of the floor coming off and legs going under the car...eek. The main floor is 16 gauge aluminum (1/2" spaced rivets underneath the car), and the 2nd floor is 16 gauge steel, with holes drilled into it to look cool/add grip/save weight (holes=speed, duh). This setup also allowed me to drive the car floorless for awhile...Im sure many test passengers wont forget that.

Image
Pre-aluminum underfloor

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PostPosted: February 1, 2009, 1:56 am 
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I have decided to go with steel, for a very popular reason (it's was free), plus I wanted the inside floor powder coated with the rest of the frame.

While I really like the look of all those rivets underneath, it seems that welding the panel would make the chassis even stronger and possibly more rigid (in my novice opinion). Does anyone have an opinion to the contrary before I burn up a roll of wire?

Thanks for the input....

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PostPosted: February 1, 2009, 11:10 am 
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Weld it in little pieces in different areas for heat distortion reasons...

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