Im wondering what grade of ally to get for my floor and how big of a sheet i will need to buy, also how you guys bonded it, im thinking silkaflex and rivets

3mm checker plate looks good. Attach as you suggest.

Big enough to cover what you need to cover - you're the designer !

3mm is a little excessive!

Mine's 1.6mm bonded and rivetted.

just to check I have this right, the book reccomends 18swg steel which is 1.22mm.

This means given densities of 7850kg/m3 and 2700kg/m3 one could use 3.54mm alluminium sheet for the same weight.

using the respective youngs moduli and some approximate breadths, for longitudinal bending one only needs 1.8mm.

Weight saving of nearly half!

(someone will be along shortly to correct me!)

But there not the same material Steel is allot more likely to take the pounding and fatigue required of a floor.

I went for a compromise and paneled where my seats are in steal and then the rest in ally. When your 70kg+ bum comes down on the seat over a hill you want to make sure the seat mounts are on something nice and solid, with a decent margin of error.

I wouldnt even consider mounting seats to the floor which is why Im welding tbs to the chassis rails for these with some proper reinforcement.

As far as being the same material, as long as youre not going beyond the elastic range then youre only interested in how easily it bends and how easily it stretches.

The only bit taking any heavy footloading is immediately ahead of the seats tbh.

Id happily use 2mm alloy for the whole lot and never think twice about it later

If your mounting it to the rails then its no problem then

[Edited on 14/1/09 by CaptainJosh]

if seats are fix on it, i'll go for 3mm.i had 2mm thick, and ali seized when i crashed...(and was not a big crash)
you should reinforce it

I would be a bit wary of ripping my knackers to pieces with a thin ally floor. Wouldn't take a big piece of debry on the road to cause trouble...