Which floor material is best for a first time builder? I haven't brought anything yet, so could go alli sheet with rivets and sikalfex (or similar), or weld in 18swg steel sheet. Or cf if someone has some going free. I've never used sixaflex and would feel better welding in some more steel, but is it worth the extra weight? Is there any difference to the car when completed, bar weight?

I would go with 14 or 16swg ali sheet riveted and bonded. Not 18swg, might be a bit thin.

David

See, I knew I'd forget something.

I have bonded and rivetted 18 swg ali, same as most westfields that I have been in.

Bonded ?

Presume this is a magic glue ?

[Edited on 23/5/06 by Macbeast]

I bought some 18 swg steel to use as floor but might go for alli instead for the sake of weight. I think other threads suggest a weight difference of about 10kg? I think that was for thicker alli though.

I might rivet rather than weld the 18 swg steel on to avoid warpage though.

When I welded my steel floor it warped so I cut out and replaced with Ali, rivits and glue....

Much nicer job.

Regards Mark

i have a chap making me a kevlar carbon composite floor for the new porject bodywork too infact

18g ally seems damned thin, i thought people used 2mm normally. Still, if it works it works

I originally welded in a steel floor but it warped really badly. I then cut it out, and replaced it with 16 SWG ally, bonded in place with silicon bath sealer, then riveted.

Cheers,

The Baron

No need to fanny about with messy glue and hundreds of rivets...

18-guage ally, 3M VHB tape, and a few rivets in the corners to resist peeling. Seats mounted on tubes though.

Liam

Aluminium, bonded and riveted would be my choice using a high grade aluminium not soft stuff (sorry cant remember the exact grade) and quaility rivets.

One thing I do consider is the safety of my backside in a low vehicle. If you happen to hit a rock or debris in the road it would rip through thin ally sheet and your ass!

Also consider that a well fitted floor will add to the stiffness of your vehicle, plus if it is extra weight it is in the best place possible place, ie as low as you can get it.

My car actually uses 6mm structural aluminium bolted in place with M6, as I want to be able to remove it.

John

6mm structural plate? Isn't that a little ott?

When I designed my chassis I tried to get it as torsionally stiff as possible with the weight in the chassis as low as possible. My studies showed that a good floor really contributed to the stiffness of the chassis, meaning I could actually reduce the upper structure.

Also engine sump gaurds are normally at least 8mm ally and as I sit on the floor and my backside is as low as my engine sump I considered my ass at least as important as my sump.

So I have a stiff structure that will protect me and my car with weight as low as I can get it.

John

Fair enough. Would you suggest putting a thicker floor in the passenger bay and use thin (18-16 swg) alli elsewhere? Do you still mount your seats on tubes, or straight to the floor?

Bear in mind that the car I built was a Morris Minor but the principles are the same.

I prefer to mount the seats to the chassis on tubes. The forces on the seats can be very high.

Having a thicker floor under the passenger compartment is a very good idea.

However many people have very thin floors and the actualy chance of something ripping through the floor is quite small (I have only heard of 2 stories) so it is a matter of judging the risk and making the decision.

John

i personally would do anything for rigidity - so would weld it in - but take my time and make sure i didnt warp the sheetstteel

What type of rivets would you use for Al sheet to steel chassis (ie steel or Al)?

Would you Waxoil?

Thanks

ally rivets, not sure on waxoyl, I haven't, but it wouldn't do any harm.

what do production cars have as a floor? i would guess steel and probably as thin as the body. i'd guess about 18swg.
of course tin-tops are far higher off te ground and have insulation in the cabin and whatnot... but i guess 2mm ally should be enough... unless you try to drive over a road block or something, then i would guess it is more probable to get struck by lightning than to have a rock up your arse.