47-55.1 Two Steps back. My high school chevy 1950 3100

[Roust]

Originally Posted by dsraven

when i did a firewall in a task force truck I used 16 ga sheet and had a fab shop do the bend. I started by hanging the doors with a good set of hinges, fit the door to the opening, then installed the latch plate and adjusted that so the door fit well. then, with the doors closed I went inside and tacked a length of 3/4 black pipe across the lower part of the opening, about 4" off the floor from the front to the rear of the opening. then a cross brace from the rear of that pipe up to the top corner of the door. then I ran an X of pipe from the lower corner on one side to the upper corner on the other side behind the firewall area to keep the front of the cab from becoming a parallelgram. do this after a few dimension checks to ensure it isn't already out of shape. then I took the doors off. the horizontal pipe above the floor allows a long 2x4 to be slid under the black pipe and through to the other side so the cab can be hung on a set of sawhorses by the 2x4's. I also braced the back of that cab but that was becuase I removed the whole floor, firewall and rear wall. I made tacks that can be ground off with a zip disc but will be strong enough to not come off while working.
I have used self tapping sheet metal screws before with success as well. a hole is a hole so even a cleco needs a spot weld when done.
when you hang the doors first there is a good chance they will fit properly when you go to install them again. lots of times I drill a small hole through both parts when they are adjusted right, mark the hinges whare they go etc, then when they go together for the last time they usually fit well.
weld through primer is a copper or zinc product that conducts the current. regular epoxy or other products may not. a tip, when you use a mig always cut the wire before you start so there is a chisel tip on the wire that strikes a spark right away and doesn't leave a bunch of contaminants in the weld from the oxidized ball that is usually left on the mig wire from the last weld.

Originally Posted by dsraven

as you know, the original cabs, and aftermarket cabs, are all spot welded together, not fully welded at the seams.you could do the same thing instead of welding the whole seam and possibly distorting the flat panels. drill through the old spot welds and clean the metal up well, do any flattening needed etc to get a nice flat surface for the new panel to sit on. place the new sheet tightly against that, cleco or screw it down tight after the weld through primier. then do the spot welds one at a time and ensure they cool off well. good clean metal, shielding gas and a auto darkening helmet with the correct shade really help. do a weld. stop and cool it, do another weld, stop and cool etc. feel the panel with a bare hand and if you wouldn't put your tongue on it because it is too hot, then let it cool off before you do another weld.

Originally Posted by dsraven

will you run a firewall booster and pedals?

Originally Posted by dsraven

if not, you could fab a few braces with a wide flange where it mounts to the firewall and use panel adhesive to keep them stuck together. its what holds new cars together, haha. that would brace the firewall if no pedals etc. I wouldn't do that if you are hanging stuff off the firewall

Dsraven,

Thanks for the description of how you braced the cab. I couldn't find plumbing pipe at any kind of reasonable prices, so I opted to go to the metal supply store and just got 8 pieces of 1"X1"X6' square tube. I'll have to cut them to length but I will start bracing soon.

The way I cut the firewall out, there are no longer any original spot welds left. I cut really high up. So I'm thinking the cut and butt method is where I am going have to go. I would love for the firewall to blend into the upper curved feature of the cab cowl. But that doesn't mean I can't try running some support midway down. I will have to seem what looks right and how adventurous I am feeling.

I will NOT be running anything on the firewall. The brakes are under the cab. The column should be going through the toe board. At least it did on mock up...