VCCA Home Forums TECHNICAL - 1945 AND EARLIER 1912-1928 What kind of wood

was used in the bodies of the cars from the late 20's?

I've read that in order to keep prices down they would use whatever was available locally at a inexpensive price.

Presently mine is all pine but it's also all been replaced within the last 10-15 years I would think. I cannot imagine pine being used, especially where it would be exposed to the elements because it would rot within a few years.

I've looked closely at pictures of trophy winning cars and in some cases I see plywood being used for the wider applications. I have serious doubts plywood would have been used also. It existed but was prohibitively expensive.

I also see oak being used, which would make sense since it is more weather resistent. It is however, considerably heavy and in an automobile with approximately 35 hp that weight could/would have a noticeable effect.

Thank you for y'alls assistence.

Hi rbl2,
My understanding is that most of what was used was Ash (poor mans oak). It has a grain somewaht similar to oak, but when cut from tree contained mush less moisture than oak. It could be air dried very quickly and was very stable, there fore less costly and a quicker time from tree to car.
John

Floor boards in the 30's were made from plywood. Ash was widely used in the Indianaoplis truck body plant mainly for it strength and machinable properties as well as availability. There are some maple pieces in my 35 truck cab as well.

our 39 woodie is framed in ash and the panels were birch veneer on plywood substrate. mike

Actually many different "hardwoods" were used. Even some white pine in the pickup bed floors and other "soft" woods (read pine, fir, etc.) are occasionally found in original bodies despite the claim in literature, that hardwood was used. Plywood was used in floor boards and top strips.

The wood bodied station wagons typically used only a couple of wood varieties as they needed to be consistant in appearance. They were built more like mobile pieces of furniture.

If the wood was covered then nearly anything was used. Ash, oak, hickory, pecan are the strongest so tend to be found in the more structural parts e.g. main sills, door posts. Popular and other weaker hardwoods are more often found other places.

There are a few diff. types of ash but the one that is most preferred is white ash for body structures and roofs. The plywood for floors is of the same that is used for hi-end speaker cabinets.Has twice the amount of laminated layers as your const. grad and is twice as strong.

Chipper,
You are right about the species of wood used. I have seen original Chevrolet wood part blueprints and under "material specified" it read: Ash,Elm,Oak Hickory, or comparable hardwoods. However, we have thousands of wood parts from Chevrolets '26-'36 which we use as patterns and they are from every specie imaginable. Mostly hardwoods, with a fair amount of "medium hard" like Poplar and even some Pine and Fir. I have several examples of Sills made of laminated Fir, with the grain in all of the layers oriented in the same direction, not alternating like in regular plywood. The plywood parts(floorboards, toeboards) which we have appear to be what I would consider typical 3/4 inch exterior pine plywood. Occasionally we find a 1/4 inch thick 3 layer plywood used as roof slats. I think cost and availibility were probably the primary considerations when Chevrolet was sourcing materials. Bill Cartwright/KC Wood Mfg.

Bill,
I don't know where the idea that Chevrolet used mostly oak or ash in their bodies ever got started. It surely is not bourn out by what has been found in actual bodies. It appears that each body plant used wood from the area of the plant or from large tracts that were owned by the car or body companies. As an example both GM and **** had large forested tracts in Arkansas, Mississippi and other southern states. That is after most of the good first growth wood was already harvested in the Great Lakes Region by the 20s.

I too have found “softwood” (for the not woodies read conifer [pine/fir/hemlock]) in nearly every location in bodies. There does not seem to be any pattern of use with the exception that the major stress areas tend to be made of the stronger wood species. I agree that poplar is found in nearly every body often the predominant wood. It is inexpensive, abundant, easy to machine, stable, holds fasteners well though not particularly strong or resistant to water damage.

Another myth is that oak was used in the beds of pickup trucks. White pine has been the wood that I have most often found. Can’t remember ever finding red oak in a truck bed with the exception of the “Bosses” fire truck. It had oak runners and cross beams. Guess the draining of water from hoses was the reason. But the bed was made by Luverne not GM. Interestingly the ’20 fire truck had redwood for the bed wood. It was the original express bed made by GM in the Oakland, CA plant. The body sides were made from a single piece of pine 15” wide. Try to find a wide single piece of pine today that would not cup or twist.

The quality of plywood used was more like cabinet grade today. With the delamination found in pieces when the wood is still in good condition I suspect the glues were more like what we use for interior grades today.

In spite of the better quality wood originally used our fastener, adhesive (read glue) and preservative (paint or coating) technology today make the wood body structure made today to be superior to the original.

I tend to agree with most everything you said. Not that I would suggest you're wrong, but it's difficult for me to imagine using an interior grade plywood where it would be exposed to the elements. I don't care how pretty it is.

I think I'll go through the back door on this one and do some research on wood/plywood as opposed to researching automobiles.

I'll get back here with whatever information I find.

Hey Chipper,
You have brought out a good point, in that the most important structural members were invariably made of a "hardwood"(oak, ash, elm, etc.) while the less critical parts were often made of a weaker specie (poplar, fir,pine etc.). I have never seen an original Hinge Pillar made of any type of medium or soft wood. Regarding the plys from that era, I agree that our current era adhesives are superior by far, but to get a bit technical here, all "cabinet grade" plys that I am familiar with have medium to hard (most often birch) interior layers with a thin outer layer of some furniture grade wood (oak, mahogheny, whatever). All of the original Chevrolet floorboards and toeboards that we have acquired as patterns seem to be made of pine. The adhesives used in making them, it is true, could be considered as comparable to "interior" plys as made today, based on how well they have held together.

To find a source for 15 inch wide stable boards would indeed be a dream come true. At some point I would love to tell you about what I have found during the restoration of our '40's era farm house. till later, Bill/ KC Wood MFG

Bill,
I guess I should have been a bit more specific in my reference to "cabinet grade". I was thinking about the adhesive and quality of the surface wood. Some are venier on a "solid core". Others are 7-9 laminate composites. There is some plywood that I have seen from Russia that is 3/4" with 7 plys and not a single dutchman to be found. Don't know the price as a buddy got some given to him. He built the floorboard and toe board for his '31 from it. Was the closest match to the original that I have seen recently. Though not too prevalent there are some "cabinet grade" pine plywoods.

I did a little research and came up with this bit on the history of plywood. It's probably fairly accurate as far as plywood goes.

I'd guess that some cars had plywood and some didn't. I just find it difficult to imagine using an expensive product that would not last very long in the application it was going to be used for.

Any how, here's the article. I may do some more research.

Ancient Origins of plywood
Archeologists have found traces of laminated wood in the tombs of the Egyptian pharaohs. A thousand years ago, the Chinese shaved wood and glued it together for use in furniture. The English and French are reported to have worked wood on the general principle of plywood in the 17th and 18th centuries. And historians credit Czarist Russia for having made forms of plywood prior to the 20th century as well. Early modern-era plywood was typically made from decorative hardwoods and most commonly used in the manufacture of household items, such as cabinets, chests, desk tops and doors. Construction plywood made from softwood species did not appear on the scene until the 20th century.

plywood Patented, Then Forgotten
The first patent for what could be called plywood was issued December 26, 1865, to John K. Mayo of New York City. A re-issue of that patent, dated August 18, 1868, described Mayo's development as follows: "The invention consists in cementing or otherwise fastening together a number of these scales of sheets, with the grain of the successive pieces, or some of them, running crosswise or diversely from that of the others…" Mayo may have had a vision but apparently not much business sense since history does not record that he ever capitalized on his patents.

From Doors to Running Boards: The First plywood Markets
During its first 15 years the softwood plywood industry relied primarily on a single market-door panels. But in 1920, "super salesman" Gus Bartells of Elliott Bay plywood in Seattle began generating customers in the automobile industry. Bartells had earlier established the first plywood dealerships around the country, and was equally successful in getting car manufacturers to use plywood for running boards. The market took off and the industry enjoyed steady growth during the Jazz Age. By 1929, there were 17 plywood mills in the Pacific Northwest and production reached a record 358 million square feet (3/8-inch basis).

A Technological Breakthrough: Waterproof Adhesive
Lack of a waterproof adhesive that would make plywood suitable for exterior exposure eventually led automobile manufacturers to switch from plywood to more durable metal running boards. A breakthrough came in 1934 when Dr. James Nevin, a chemist at Harbor plywood Corporation in Aberdeen, Washington finally developed a fully waterproof adhesive. This technology advancement had the potential to open up significant new markets. But the industry remained fragmented. Product quality and grading systems varied widely from mill to mill. Individual companies didn't have the technical or in most cases marketing resources to research, develop and promote new uses for plywood. The industry looked for help from its newly formed trade association, the Douglas Fir plywood

fbl2,
Great research into plywood. I am sure none of us knew that plywood development went back that far.

On the comment, "I just find it difficult to imagine using an expensive product that would not last very long in the application it was going to be used for." I will offer a possible rationale. The glues, hide glue was one of the main ones used, had some resistance to water as does the glue used today in interior grade plywood. I suspect that the failure of the glues and therefore delamination occured slowly and not consistantly across an application. Also the stability of plywood compared to one ply (solid) lumber was so much greater that I am sure other problems (like occasional delamination) were tolerated. Once delamination was understood to be from water deteriorating the glue bond, then the chemical research guys got busy looking for other adhesives. It took a while to develop and test phenol-formaldehyde adhesives that are very moisture resistant. So it took many years to identify and then come up with a solution.

I've been...or was... in the building trades since 1968. I spent my years working in one form or another of carpentry and field engineering. My little trip to Iraq has put an end to any thoughts of ever again working. Point being, I have at least a few days experience with wood, as I'm sure others in this forum do.

During my career I've seen how the elements can affect both interior and exterior grades of plywood. It doesn't take much water to cause either to swell, delaminate or bubble. Marine grade plywood on the other hand is quite stable but VERY expensive.

As far as the stability of interior grade plywood vs air-dried lumber goes, I would use 3/4 or 4/4 air dried lumber in an exterior application before I would even a high grade interior plywood of the same dimension. Even exterior grade plywood would succumb to the elements but then so would air dried lumber, just not as quickly.

Plywood, IF available, would be less labor intensive then lumber as it can more readily be cut to length and width with there being no concern for thickness as that would be predetermined.

I also agree with KC_Wood when he says, " I think cost and availibility were probably the primary considerations when Chevrolet was sourcing materials. Bill Cartwright/KC Wood Mfg."

If I can find a piece of high quality, interior grade plywood I'll do an exeriment and leave it exposed to the elements, along with some oak, pine and what not of similiar diemnsion just to see what happens.

I thought that exterior grade and marine plywood used the same adhesive, the difference between them being the number of plys with marine having a couple more layers per a given thickness and better quality wood with fewer voids.

Googled, copied and pasted....


Name: -Plywood

Sources: -Plywood is made by gluing together a number of thin veneers or plies of softwood or hardwood.

Advantages: -There is always an odd number of veneers and each ply is at a right angle to the one below, this gives the material it's strength. The more veneers used, the stronger the plywood becomes. Both the type of glue and veneers determine the suitability of a sheet for a particular application. The finish quality of plywood varies considerably, some plywood have attractive grains while others can contain knots. Plywood may be used inside and outside. Plywood is graded for exterior or interior use depending upon the water resistance of the glue used to stick the plies together. Code letters shows this grading on each sheet.


Exterior grade plywood (WBP - Weather and Boil Proof). This type of plywood can be used outside. Water-resistant adhesives are used and can resist a certain amount of moisture.

Uses: -Sheds and cladding are made from this material.

Weather boiled proof plywood requires paint or varnish to protect the outer veneer from the elements.

Internal plywood does not contain water-resistant adhesive. The code used to represent this plywood is (Int.interior use only).

Uses: -It may be used for wall panelling, flooring and furniture.

Uses: -Shuttering boxes are made from shuttering plywood. Shuttering boxes are used in the construction industry to contain concrete while it sets. The material is water resistant to a certain extent. The surface of this material does not have a decorative veneer and is generally not suitable for use where an attractive quality finish is required.

Uses: -Marine Plywood is made with waterproof adhesive so that it can be used under water. The material should still be protected with paint or varnish.

Other codes used on the surface of plywood are: BR: -Boil Resistant, MR: -Moisture Resistant.

The smoothness of the surface and the number of defects in it grade plywood. Plywood can be nailed and screwed. Thin plywood is flexible and can be formed into curved shapes.

Out of the 20 or so 34-35 trucks I have owned all of them had plywood toe and floor boards. The wood would have to be too thick to span all the across the floor as there are no braces in the center to support a 3/4" thick board.

I have owned my 1933 coupe for 42 years. The first thing I replaced was the toe and floor boards, so they are at least 40 years old. I used regular exterior plywood and painted them with several coats of exterior enamel. They show no signs of wear or delaminating and I have removed them many times since first installing them. I usually seal the outer edges with duct tape between major accesses.

Roger

Hello IMFALCO,
I think you have done what a lot of other antique Chevy owners have done. That is , replaced your old, original floorboards/toeboards yourself, with readily available 3/4 inch exterior pine plywood such as is available at any local building supply store. GOOD FOR YOU! It will serve you well and probably hold up long after you and I are gone. Bill/KC Wood

I have what may be original floorboards in our 28 sedan. It does not have plywood but pine finished to 3/4"planks, edge glued and with 2 3/4"x2" cross braces. The holes for the access and cutouts appear to have been routered simular to those in the doors, there is no cutout for access to the battery, which makes me doubt the originality . I don't know whether they are replacements or original.The floorboard fits very close. The car was built in the Janesville plant.

Hey Mr. Mack,
I have original floorboards/toeboards of solid wood made the way you describe, always 1928 or earlier. Look on the bottom of yours, do you see slanted notches on the edges where the various mechanical parts come through? Do these notches look "factory made"? I know this is a vague description but , you can always tell if a floorboard /toeboard is original by the way the various cutouts and notches are made. From your description, I would guess that yours are original. Bill/KC Wood MFG

KC_Wood, Yes, the floorboards are as you described them

The only post '28 Chevrolet that I have found with solid wood floor boards is our '31 firetruck built by Luverne in Luverne, MN. I agree that in nearly all cases the solid floor boards have stiffeners glued and screwed to the bottom to prevent splitting, sagging, etc. Many of the toe boards did not have the stiffeners.

Mr. Mack
My unrestored 28 coach also came from the Janesville plant, and is the same as yours, and yes mine has all the cut outs mentioned by Bill. The one piece floor board with no cut out for the battery is a pain in the *&% for checking the battery
Chris