Technical Bulkhead between trunk and cab - what to use?

'31 Model A coupe with gas tank mounted in rumble seat to trunk conversion.Considering using 1/2" Russian birch plywood in lieu of 16 or18 ga. sheet steel. Any advantages/disadvantages to using one over the other to separate the trunk from the passenger compartment?

Don

 

I would use the plywood , it would reduce the interior noise and it's strong .

 

Plywood would burn in case of a rear-end/fire. That said, the yellow roadster in my avatar had plywood behind the seat

 

plywood with 22 gauge steel covering it? best of both worlds, and you add some of that much-needed weight

 

Sound considering here! Each has their properties. I would use 18 or 20 ga w/an X bead rolled in it. Have built (2) 31's, you want safe & quiet in a Coupe. Fit window channels, door gaskets, insulation paneled interior. Squirrel got it right!

 

You can call it a bulkhead, but I call it a firewall. Fire and wood don't seem to go together well to me. I used bead rolled 20 gauge tightly sealed and the peel and stick stuff for sound suppression.

 

I had a steel 1 x 1 frame between the trunk and cockpit so it was easy to weld in a piece of 16 ga. steel.

 

do not understand the use of wood where metal should be - all types of heat/sound insulation out there - be sure to seal off and ventilate gas tank area

 

Thanks all for your replies and suggestions. Normally, I consider a firewall the structure separating the engine compartment and passenger compartment - just used bulkhead to define the location more than the function.
I like Jim's idea to use both, and I may go that route. Plywood for mass and strength, and steel for fireproofing. Ventilation and sealing the trunk compartment are high priorities - thanks for the reminder!
Don

 

Hey Don, I'm a little late to your thread but this topic was really on my mind when I was planning my 30/31 A coupe.

Metal, to me, seemed like the obvious choice because it could also be used to stiffen up the body. Not only is it welded to the bulkhead braces and the floor, it's welded to the body where it's chopped.

 

Never too late - it takes me a while to get anything done! I did decide on using metal for the bulkhead/firewall. An angle iron frame will hold the metal in place, but I've got more work to do before that happens. Additional bracing is needed to install the three point retractable seat belt (thanks to Rich B.'s coupe build). Your bulkhead looks great!