I'm about ready to set my Model A coupe body back on the chassis and have a question about the floor. I want to use plywood instead of replacing with steel. Any problems with doing this. I know steel is stronger but just like the plywood. anybody
I'm using steel up to the front edge of the seat and plywood from there forward. Two pieces of plywood as the toe board is another piece. They bolt in and are easily removable if need be. Also makes it easy to mount your gas pedal, high beam switch, etc...
Jack,when I built my Model A pickup I used marine grade plywood with no ill effects,,I say go for it. BTW,your frame looks great! HRP
I used plywood that I primed and painted, been that way for 20+ years. No regrets and has seen typical wet driving conditions with no ill effects.
Thanks fellas, I'm going for the plywood. I'll post some pics as soon as the body work is done and the coupe mounted on the frame. Getting ready to ride a bit.
I've always used 3/4 inch solid core plywood( so called "furniture grade") from Home Depot. You can get a 4X8 sheet when it's on sale for about $50 bucks.Does a Model A with some leftover. Don't buy the cheap stuff- it's full of voids and isn't laminated well.Primer, and 2 coats of black Rustoleum oil base, and she's done. I always put a little extra on the edges; if water infiltrates, that's where it's going to happen.Skill saw, jig saw, hole saws and drill bits, and you're off to the races. Good luck with it. I tried to show the finished product in the second picture, then realized the front floorboard and battery box door are stacked up in there too- I guess you'll get the general idea.
Here's another case of wood being the material for the job. In a floor, stiffness is a far more important consideration than sheer strength. A ¾" plywood board is a lot stiffer than an equivalent weight of steel plate when laid flat as in a floor. As steel has around 14 times the density of plywood an equivalent weight of it is only about 0.55" thick, which is much easier to bend than ¾" ply even if it will carry a far greater load without breaking. To match the stiffness of the ply we'd have to make the steel a lot thicker than is needs to be strength-wise, or otherwise expensively press ribs into it. So much for the engineering; the political economy of the question is that it is a mistake to believe that every innovation (or even most) that the OEMs devise are about improving the product. In other words, the fact that steel floors came after wooden floors does not mean that steel is better. It doesn't even present a convincing argument that it might be better. The bigger OEMs went from wood to steel because wood is just too easy, and many of the smaller manufacturers followed suit because they fell for the big guys' line about the Wave of the Future etc. and ultimately paid the price for their gullibility. From around 1934 the automobile was increasingly specifically designed to be impossible to reproduce at a volume less than that of which the big OEMs are capable, in order to eliminate smaller manufacturers who might eat into the demand that the big OEMs' huge output requires. Government collusion was part of this from the start (it used the sealed-beam headlight to kill an entire independent lighting industry in 1940) and the process is, as we all know, ongoing.
Using plywood for my coupe as well. I like the fact that I can remove it if I need to service anything as well as the sound and heat insulation factor.
I have also found , over the years, that plywood does a very good job of providing insulation to floorboards. I usually use it on the inside (cocpit) side of steel firewal tool; again a good insulator. Oh, and you can use screws to attach lighter weight objects, wire bundles etc. to it as well
My stock '37 Cadillac has plywood floors from the front seat forwad, steel in the rear. I was going to use wood in my Model A when I built it but ended up with steel. I found it was easyer to just roll some beads and lips and weld them in. the only trouble was making the two sides removable but even that was not too hard.
I thought these dimensions might be useful, Floorboards http://www.stevewatrous.com/modelaford_p2.html It might also be good to compare the price of completed boards with doing it yourself. I think the boards would be quieter and marine plywood should last as long as you own the car. Charlie Stephens
As stated, plywood is a better sound insulator and heat barrier. Lotus used it in there mid-engined Esprit, to keep engine noise and heat from the cockpit. Ago
Some places try to pass off common treated plywood as marine grade, but true high quality marine plywood is not pressure treated as a standard thing. Aside from the fact that you wouldn't want any treated wood in the vicinity of steel because of the corrosion problems, treated plywood won't hold paint or resins like polyester or epoxy unless its been kiln dried after treatment. Even then, the moisture content can be high enough to prevent it from taking any sort of finish. A 4x8 sheet of 3/4" Grade 1088 marine plywood made from Meranti or Okoume (species of woods) will cost $150 to $175, but its worth every cent of the price as compared to standard plywoods for this sort of application. What you're paying for is high quality, very thin plies all the way thru the sheet. Common plywoods have voids within the plies, and when exposed to water the water will eventually find its way into these voids. Then if its later exposed to freezing temperatures, the water in the voids freezes and starts to separate the internal plies, creating even bigger voids where even more water can collect. Start with top quality marine plywood, coat it with epoxy resin on the side exposed to potential water, and then paint it with whatever you care to use. It'll be there from now on.
Beware of meranti. Besides the shoreas having shortcomings of their own, old south-east Asian growths of meranti are getting depleted, with the result that any damn thing is being sold as meranti these days.
As stated earlier, I have used solid core ( furniture grade) plywood for years with 2-3 coats of good oil base paint, and have had no problems.I tend to think that marine grade is overkill ( especially the price) and you shouldn't need it unless you're driving to England.Then I'd use teak with Danish Finishing Oil on it, and install a bilge pump. ( just a joke, take it easy)Bottom line is, it all works and it's up to the individual- get it done and DRIVE it! ( I'm just a cheap Yankee, and love to stretch a buck till the Eagle screams)Speaking of sceaming, that little A bone coupe ought to scream with the motor you put in,Smilinjack!!
I'll second what Mike above says regarding marine grade. I have A/C 3/4" plywood in my Model A, been there since 87, just a coat of polyurethane and that's it.It has held up just fine.
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