Expanding foam race seats

I'm about to attempt one of these for track days in the Dax and it looks to me like one of those jobs where your second/third attempt is going to be infinitely better. Being impatient and short of time, I'm keen to shortcut that and get it right first time. Does anybody have any pearls of wisdom they've picked up or any links to recommended walkthroughs?

So basically: RTFM

Don't copy the crutch strap design though, it's a complete waste of time having proper MSA/FIA approved mountings on the end of the strap when most of the force is now taken by a flimsy bar bolted to the alloy floor panel. That would likely rip out very quickly in a roll, and then you suddenly have an extra foot or so of vertical movement.

in stead of the expanding foam you can use bean bag beans and a vacume storage bag.

you put the beans in it, sit it in the car and get it roughly to the right shape adding or removing beans as required.

once the correct amount of beans are established mix up some glue and pore that into the bag as well. mix the beans and glue and sit it back in the car and adjust so that you have the support where you need it. once happy apply vacume to the bag so that it holds the shape you set it in then hop out of the seat and let it cure.

much safer than the expanding foam stuff as it shouldn't produce cyanide gas in a fire and you also have less chance of burning yourself as it expand, sets and goes off with you sitting in it to make the mold.

Ryan

Mostly all the seats I have done have been in single seaters but the basics remain the same
Firstly make sure you are perfectly set up in the car seat position,seatbelts,pedals etc,in most cases you will want to be as low as possible in the car but if you do need to be raised up from the base of the seat get some foam or wood so you have something to sit on you dont want to be trying to hold yourself in an artificial position.
Mix a small sample of foam to get an idea of the expansion,it varys from foam to foam and temp also affects it,be careful to mix equal amount of A+B and mix it very well.
Dont to do it on your own your job is to sit there ! someone else does the work. I use vac bag and tailor the shape to the seat,best you can aim for is the large wheelie bin bags.try to get heavy duty
Depending on the car/seat if there are holes,gaps or undercuts where the foam could push the bag into and cause removal problems I tape over them with masking tape
It varies on the car/seat/driver position but you can do the seat in one or several pours.set the bag central and see how much "spare" bag you have and if you have lots of extra in certain areas roll it up and tape it up to make a more suitable shape,you dont want to be filling a bag with foam just for the sake of it.
If your going to have a fair bit of foam under your legs pour some into that area before you get in and get strapped in,once your in you want to be sitting in your straight ahead driving position,fully strapped in but dont worry about a croutch strap, an let the foam set around you in that position,its an exothermic reaction and you will get warm but dont worry it soon passes
As the foam comes up your back your assisant wants to be controling the foam,I normally seal it behind the neck area and have a vent over each shoulder so if it not coming up one side you can close the opposite side ,once you get use to it you can get a lot of control over the foam,also you want to keep the foam under a little bit of pressure ,it has a lot more strengh than foam that has "free
" expansion
Dont let the foam lift your legs or push your shoulders forward,once the foam has done its stuff stay in the seat till the foam fully sets and isnt spongy
Better to mark up and trim out of the car then you dont cut through belts,wiring or exstinguisher pipes (seen all 3 done !)you dont want to cut too much but allow for full steering lock each way an gear changes

Thanks for all the advice guys. I'm jiggering about with the floor and pedals at the moment but hopefully that's all done by the weekend and I can have a crack at the seat.