On some early cars, the firewalls are horizontal or vertical tongue-and-groove boards with a thick veneer over each side.
Is this the case with early T firewalls and, if so, what is the width and configuration of the boards?
This is the case with all wood Model T firewalls. The lumber core boards are random scraps glued together.
Its interesting that the firewall being held looks like it has only the glued up core boards running vertically, without the outer veneer layers that would go horizontally. This would seem to indicate that the outer veneers were glued on after the firewall blank was shaped and all holes drilled. Maybe this photo was taken just to show what those glued up blanks would become.
The dash that the guy is holding is at least a 1919 or later since there is relief at the bottom for the starter clearance. During that time they made several versions of the dash all at the same time. The regular veneered design had a 9/16 core and a veneer on each face to make it 11/16 thick. On 5/7/19 they added a 4 piece design with 4 plys to be either White Ash or Northern Maple. On 6/4/19 they specified that the dash was to be dipped in solution of 75% boiled linseed oil, 10% turpentine, 15% Japan Dryers. This change was to prevent warping. (Regan note - lots of references on dash drawings that indicate warpage was a constant issue finally only resolved by metal firewall or it would seem so). 10/16/19 the 4 piece design now allowed Oak, Mahogany or Sycamore in addition to White Ash and Northern Maple. Likewise the veneer design also allowed the same woods having been previously specified as White Ash or Northern Maple only. Also on 10/16/19 they added a 3 ply design with 3 equal plys with outer plys running Horizontal and inner ply running Vertical. Then just 2 days later on 10/18/19 they obsoleted the 4 piece design. Hard to get many details on the 4 piece design. It did not say that the 4 piece design had 4 equal plys but one would assume so. On 10/20/19 they changed the 3 ply design to have the outer ply running vertical and the inner ply running horizontal. They also stated that for the concurrently running "veneer design" that the inner core was to be vertical and the outer veneers to be horizontal. (Regan note - it seems they wanted more of the wood to be vertical than horizontal). On 12/11/19 they specified that the 5 woods previously mentioned could only be used on the 3 ply design or the CORE on the veneer design but that face veneers on the veneer design had to be Maple, Northern Maple or Birtch so birtch plywood facings would be incorrect before mid 1920 (model year) cars.
If the above information answered your question -- that is great. If not, recommend you specify what year dash you are interested in (and as John Regan pointed out -- the month and even day can be a factor). As the term "Early Model T dash" might mean 1909 to some folks or 1920 to others.
Thanks for the great information so far!
Hap l9l5 cut off
Well it looks to me then that the firewall in hand is the type with the 9/16 glued up core, since there's a bunch of cores about that size being clamped. But the one he's holding looks like it has no outer veneers---looks like its just glued up boards. So WASUP?
And thanks for all that info John!
Good point! I meant to put the year in my original post. My inquiry revolves around 1910 - 1911.
Thanks for all the great feedback and the marvelous photo.
I think that is just the core too Ray. I would guess gluing the veneer on each side is the next operation. That thickness of veneer would be just splinters if they tried to drill all the holes in it first. I bet that firewall took at least 2 days to make with the drying time of the glues back then. Maybe the old time hide glue and a press?
If they were using hot hide glue (common back then) the glue would be set enough when they finished the last glue up on that rack to start taking off the first one. The glue would need another day to get to full strength still!
If the veneer went on after the holes were drilled it would seem like a lot of extra work steps just to prevent some splintering. only the larger holes do not have their edges even visible after construction so why worry about splintered holes when a bracket and/or bolt head will cover it anyway. The picture is too fuzzy but it appears that the dash he is holding might be absent the smaller holes. My old eyes can only see the bigger holes are there for sure. Does the original picture have better focus so as to determine if the mounting holes for the steering column, coil box, dash-to-frame brackets...etc are also drilled?
I agree that the dash boards in the clamp clearly are thicker than would be used on a 3 ply dash. I wonder though if what might be pictured is a 3 ply dash which is being shown here for comparison or something. This could easily be at a time when they were using both versions.
Don't forget that after gluing, and curing, the core would be run through a planer so the surfaces would all be the same. This would make the finished core thinner.
Were there ever any firewalls (1909-22) made with the outer veneers vertical? Maybe for this photo a firewall shape was cut, along with some drilled holes, to just hold up there and show what those glued up blanks are for. It wouldn't make sense to put the outer veneers on after making those holes.
That is an interesting glue up apparatus. It looks like they rotated it till it was tilted just right, laid the stock in place with glued edges on two fixed cawl braces, then maybe pulled another caul down on top to keep the glued up stock flat, and then used three clamps. Then tilt again and do another.
Since they were using scraps, the vertical orientation of the boards was probably the most practical way to get the best yield, and putting the veneer on horizontal provided strength and helped prevent it from splitting.
I don't think it likely you'd see a finished vertical grain firewall if it meant having to rearrange how they clamp-up the blanks.
Do you suppose those boards came from parts crates or new kiln dried wood? I've heard stories that Ford used crate wood for floorboards and that some members actually have stenciled writing on their floorboards from old parts crates in which parts arrived at the factory in, to bolster this story. It sure would save money to use free wood from crates as opposed to purchasing new wood from the mill for millions of cars. Jim Patrick
Crate wood was not used for anything other than crates. Ford would not have used wood that already had nails in it. The amount of time that would have been consumed pulling all the nails and sorting through wood that was damaged by nailing would have made such an idea impractical, despite all the old wives tales.
Ford did use scrap wood to make charcoal briquettes.
Thank you, Royce. Don't you think that they could have used boards from the longer crates where the only nail holes would have been on the ends? I'm sure Old henry would have given some thought to using something obtained for free and onsite, as opposed to purchasing it and paying shipping on it. The labor to pull the crates apart would have been the same for new lumber that would have needed to be shipped in, off loaded and transported to the assembly area anyway and crate and pallet lumber would have been free. When you're talking about millions of cars, the savings could have been substantial. Jim Patrick
To clarify my earlier post, I didn't mean to imply scrap in the sense of discarded material from broken down crates, etc., but rather drop-off from some other process as everything seems to be random lengths.
Either way, it's immaterial as the point I was trying to make was with respect to direction of layout. From both a strength and yield standpoint, I don't think it would make sense to run the joints from side-to-side.
It seems like, if the boards were ordered from the mill for the specific purpose of making the firewalls that they would have been ordered in a specific width so as to avoid excessive drop, however, in closely looking at the boards on the assembled firewalls, I notice a wide variety of widths from 1" to 3" or 4", which seems to indicate that either the boards are from another source such as crates and pallets or the drops from other woodworking departments such as body framing, top framing or top bows. Same goes for the wood floorboards. The wood floor boards on my two '26 closed cars consist of larger boards made from smaller boards glued and clamped together. If Ford was so concerned with labor, then why did he not order the floorboards in the correct width and save on the assembly time needed to put the pieces together and the time needed for them to sit for a day to cure, in order to make a larger board from smaller pieces? The only answer seems to be that he was using the drop or scrap he had on hand to save in material costs. Not an outlandish concept. Quite the contrary it seems like exactly what the frugal Ford would have done when seeing the stacks of crate lumber that would otherwise have been discarded.
I have used hide glue flakes in a melting pot and it is still one of the stongest exterior wood glues available. Jim Patrick
PS. It is common practice for a woodworking place that manufactures wood products and finish carpenters doing trimwork in a house (ie, door trim and baseboards) to cut the larger pieces first then use the smaller drops to make the smaller parts. It is conceivable that Ford did this, sending the longer boards to the areas that required long cuts such as the top frames and body framing then transporting the drops to areas that required shorter pieces such as the firewall and floorboard assembly areas.
If i rember right there were templates used to get the most pices of usable lumber/parts from a board? The Ford Indstury's is a great place to find how and why! Bud.
I don't know if this firewall is even original, but just happened to come across this pix looking for something else.
I have no clue where this pix came from or why just happens to be on my hard drive.
The file date is January 31, 2005 and the original file copy is bigger than a pinch from the forum but it shows vertical graining.
I can't be sure George, but that wide, flat, consistent graining, all the way across the firewall appears to be plywood. If it were made of smaller pieces as shown in Royce's picture, the wide grain would be interrupted by a variety of different grains across the firewall. Jim Patrick
Jim, More importantly, that wide grain shows it to be a softwood, and peeled cut, so it's modern.