Posted By: FlyFish
Making a Rear fire wall, help please - 06/13/12 02:46 PM
I’m putting a fuel cell in my trunk, so I guess it is time to put in a rear fire wall (I assume it is an NHRA requirement, but I have never checked). My question is, what materials do most folks use for the fire wall (aluminum, thin sheet metal, etc,), where did you find said materials, and how did you make it?
I’m thinking of just starting with a piece of cardboard to make a template from the back seat area, but I was not sure where to get the metal (or what kind).
Thanks in advance for any help or pointers you have.
Posted By: jamesc
Re: Making a Rear fire wall, help please - 06/13/12 03:19 PM
aluminum minimum .032" thick (20 gauge) or steel minimum .024" thick (23 gauge) most use aluminum that's what i'm using. just about any decent metal supply should carry both. cardboard template would be a good idea
Posted By: Clanton
Re: Making a Rear fire wall, help please - 06/13/12 03:24 PM
Like said i made a template of caedboard/posterboard taped togather and then went to aluminum and i screwed the final product to the floor,seat support,hammered over the hook for the rear back seat.
Posted By: Clanton
Re: Making a Rear fire wall, help please - 06/13/12 03:34 PM
not the best job but passed tech no problem.I called the tech at the track i go to to make sure what i was doing would pass.
PS: Yes i messedup on the seam with an arch being there and i used the streight edge of the sheet of aluminum [4x8]
the 4x8 is not big enough to get both cuts from and i was making a console at the time also so i had several sheets that were about 20$ each.
Posted By: joshking440
Re: Making a Rear fire wall, help please - 06/13/12 03:54 PM
Get a perfect template made from nice white poster board and I will get your firewall made for you.
Josh
Posted By: polyspheric
Re: Making a Rear fire wall, help please - 06/13/12 04:25 PM
completely sealed to prevent any fuel from entering the driver’s compartment
Passes tech? Depends on how busy they are. "Sealed" means liquid cannot pass through the seam, so sheet metal screws, etc. are not legal.
A better question: if it's not completely welded or tightly riveted, what material is acceptable as a gasket? Obviously, not something soluble in fuel, but how about seam sealer (like for body work), window caulk, form-a-gasket???
Posted By: Jeremiah
Re: Making a Rear fire wall, help please - 06/13/12 04:38 PM
In the past we have used butyl tape and urethane sealant around the edges/holes in the rear firewall. It can be a real pain to get everything laid out and you might want to find someone with a CNC waterjet to cut the metal. It turns out much nicer that way.
Posted By: astjp2
Re: Making a Rear fire wall, help please - 06/13/12 08:20 PM
This is the stuff you should use to seal against fuel, its used to make riveted together aircraft fuel tanks. Price is affordable. Tim
http://www.vansairforce.net/articles/tank_sealant.pdf
Posted By: curleysracecars
Re: Making a Rear fire wall, help please - 06/14/12 10:39 PM
Carboard is your friend. I can buy flat sheets from a local shipping supply company for about $6. Cut it up, and make multiple individual pieces if need be. If you too much away in a small place or something...dont toss it. Take masking tape to fill in the void where the cardboard was cut too much. Once you are comfortable, I will usually transfer all modifications to a new fresh piece of cardboard and cut it out to make sure everything is kosher. From there, I go on to using .040 aluminum. (Use 5052 series material if you intend on bending it).
When a template is done, it looks like a novel...I have notes written all over it. "Add 1/8" here", etc. Good luck. Remember cardboard is cheap...so get the template perfect.