…And a Few Other Tips on Restoring and Repairing Automotive Wood
At one time, wood was fairly common on automobiles, both in the structural frame and the cosmetic finish. Except for the British-built Morgan, though, the use of wood today is largely limited to interior trim on exotic luxury cars, such as the Maybach and Rolls-Royce. (But, in some cases, the material might instead be a cleverly crafted synthetic substance.)
So don’t be surprised when tackling a project on an older kustom or hot rod if you find a “termite farm” underneath the skin. Of course, the material on a traditional woodie’s exterior finish is obvious, but restoring that type of wood requires some specialized approaches, and entire books have been written on the subject. We’ll focus mostly on the structural aspects of a couple classic vehicles at Full Circle Restorations, since the basic techniques, tools, fasteners, and materials are all fairly similar, whatever the year and make of vehicle.
Removing the metal skin (if there is one) is usually the first step before replacing or restoring any wood components. This is easier said than done, especially on an old, weathered vehicle with wood that has deteriorated.
The sheetmetal is usually nailed in place, and those little fasteners can be a pain to remove, especially the brads. Here’s a handy tech tip: think small, as in a toy-sized claw hammer with a removable head and several other tools in the handle. Drive the claw of the hammer under the sheet metal on either side of a nail and then pry up the nail, hopefully with a minimum of damage to the sheet metal.
On some older cars, such as the 1930 Cord shown here, Full Circle’s Tom Van Steyn encountered some lead on the heads. “I first had to melt the lead, using the flame from a small bottle of propane,” he explains. “Then I used a small crow’s foot tool or nail puller to get the nails out. Or for hard-to-reach areas I’ll make a tool from a flat, stiff scraper, cutting a notch to grab the nail.”
Getting out the screws from the wood frames presents its own challenges. To make things go more quickly, thoroughly clean the slots in the heads of the screws with a knife. Also, make sure the blade of the screwdriver is flat and that the edges have not become rounded. Otherwise, regrind the blade.
“You gotta make sure the blade matches the screw head,” Van Steyn notes. “Or drill out the head and pull on the nub with vise grips.” Either way, you’re looking at a fair amount of elbow grease to disassemble a wood frame (but probably less work overall than sheetmetal construction).
Woodworking tool companies also offer a special type of screwdriver than turns when you hit the top, so you don’t have to twist it by hand. Or you can try using a brace or ratchet and a screwdriver bit.
Dismantling the old wood might also require using a glue dissolver on some later models (Van Steyn says that the glue on older classics, if present at all, has usually turned to dust). Apply the dissolver along the edges of the wood where it is held into place inside or outside the car. Once the assembly glue is dissolved, be sure no screws are holding the wood in place, and then pry the wood pieces out with a screwdriver or other flat object. Take your time and let both the dissolver and woodworking tools do the job for you as much as possible. Otherwise, you’ll end up frustrated and want to use your wood-framed project to light a bonfire.
Once you’ve removed the wood pieces to be repaired or restored, inspect them carefully for dry rot, crumbling, or insect damage that will need to be cut away or repaired with epoxy filler. For the latter, Van Steyn says he’s found some success with wood restoration products offered by Smith & Co. A two-part epoxy is used to penetrate and repair cracks, and also kills rot and bugs. Then it’s followed by an epoxy filler that can be drilled and sanded, and which locks down the grain of the wood.
Take care not to damage any original pieces in good condition, and keep tracings and photographs of the damaged sections to use as a template. Next, you can clean the frame components with a wood oil or wood soap, removing all grease, grime and insulating material. For cosmetic trim, apply a generous amount of wood stripper (again, let the chemicals do as much work for you as possible) to lift off sealer and stain. (We’ve heard that TSP or acetone might work as well, but test any strong chemicals on a scrap piece first before using them on the actual parts to be restored.) After allowing the stripping solution to sit for 10 minutes or more, use a putty knife to peel away the layers of finish. Then sand the wood thoroughly to remove all traces of stain.
If the wood is darkened or discolored, bleach it to return it to its original color (for details, consult Rick Mack’s Wood Bleaching Guide). If you don’t do this, it will stain to a different color than any replacement wood.
When restoring original wood pieces, you’ll probably need to fill the small nail and screw holes with toothpicks or matches dipped in the epoxy. Screw holes that are rotted or damaged can be repaired by drilling them oversize, and then inserting a piece of dowel rod which has been dipped in epoxy.
After filling these holes, you can brush on the remaining epoxy to seal the wood. After it dries, sand each part with 60 to 100-grit sandpaper and apply a second coat of epoxy before reassembly. Instead of coating each individual part, you could coat the entire wood frame with the epoxy, but don’t do that if you want the option of disassembling the wood at some point without having to cut it apart.
If you can’t restore the original wood components, before replacing them, determine what type it is. If it’s a rare or exotic wood, or an unusual size, you might need to order it from a specialty hardwood company. Van Steyn says that oak is a typical choice, but often coachbuilders used whatever was readily available.
“I use ash because it’s a little denser,” he says. “It’s what they make baseball bats out of, and has a tighter grain than oak.”
Depending on the type of frame member, reproducing an original structural piece might be as simple as using it to trace a pattern on a larger piece of wood with a pencil, and then cutting it to fit with a band saw (or coping saw if it’s a small or delicate piece). To get the final shaping accurate, clamp a template (either the original part or a poster board pattern) to the part and sand the new part with a belt or disc sander until they match. Other useful tools for matching contours include a compass protractor or scribing tool.
You might be surprised to find, though, just how rough some of the cuts are on the original wood structure, so don’t feel your workmanship has to be as precise as furniture or finish carpentry (unless you just happen to be very meticulous). As long as everything fits together fairly snugly and supports the body, you’re in good shape, because it’s usually going to be covered up anyway. Keep in mind that some gaps are needed to allow for expansion, and if the structure is too rigid, it can split. And you might need to add some jute backing to minimize creaks and squeaks.
Fasteners are whole ’nuther subject. Van Steyn says he uses zinc-plated screws, but, “The biggest problem is finding slotted wood screws – everything is now mostly Phillips, which didn’t come out until the Forties.”
Even when you can’t see something, authenticity is still important. But the good news is that on restorations, “Wood goes pretty quick. It’s faster than metal, since there’s no welding and grinding,” he adds. And just remember to go with the grain.
Full Circle Restorations 209-727-3322 www.fullcircleresto.com
Smith & Co. 800-234-0330 www.smithandcompany.org
Some of the older wood frame pieces might need just a bit of sanding, such as the doorjamb on this 1930 Cord L-29 Cabriolet. Fortunately, the car had low miles on it, so there wasn’t a whole lot of wear and tear.
Note the intricate workmanship on the rear quarter. Some pieces had to be replaced because the car was converted to run on propane in the Seventies, and the framework had to be returned to original using another Cord as a pattern.
The joints have gaps on the original wood, probably to allow for expansion.
Note the hand-shaped corners and recess for the convertible top mechanism. They don’t make ’em like that anymore.
Tom Van Steyn of Full Circle Restorations holds up a piece of the original main wooden framework next to a new piece bolted on the metal chassis. Since it’s such a critical piece, it has to have a straight grain with no knots or checks; otherwise, it will cup and move.
The white material is an epoxy filler, ideal for repairing minor cracks and defects. Note the slot-head screws, which were standard fasteners back in the day.
Old wood needs to be probed with an awl for rot and damage, and removed if necessary.
Structural support is screwed to the wood with slot-head screws.
Hole saws of various sizes are used to duplicate shapes.
Note the radius area at the lower left section. The replacement floorboard will need to be shaped to match this section.
Note the careful reproduction of the original frame for the golf bag compartment. Some of the original wood had been cut out for a propane tank, so Van Steyn took pictures of another Cord being restored to duplicate the original configuration.
The metal tray for tools is located behind the seat. It was mostly for storing a wrench and lead hammer to remove the spinners for the knockoff wheels.
Note the rough, hand-chiseled cuts in the center bow. This stepped area nestled the Cord’s trunk latch – a bit crude, but effective.
Here is the reframed opening for the golf bag compartment.
Note the combination of wood and steel components in the body and chassis of this classic Cord. The wood actually made for a somewhat softer ride, since it gives more than steel.
Original wood components are used as patterns, sometimes for the corresponding piece on the opposite side, in case the original is severely damaged.
Certain non-standard thicknesses of wood might not be available at your local lumberyard and have to be special ordered.
A bit of sculpting will be necessary to replace some components, such as this door-hinge post. Start with a rough overall cut to check for fit, and then make the smaller cuts for the hardware using a chisel and hammer or a router.
Clean off any insulating material and remove grease and grime with wood oil or soap.
Simply trace the old part over a larger piece of new wood to create a replacement part. Note, though, that you’ll also need to reproduce some compound curves, angles and shapes as well, using a scribing tool or compass protractor.
Use a drill press and mortice and tenon bit to form a square hole.
Band-saw blades come in with different sizes and number of teeth per inch, for both rough and fine cuts. Thinner blades are more flexible for more intricate cuts.
When cutting with a band saw, push the wood through smoothly, and avoid binding the blade with sharp turns. A table saw can be used for straight cuts.
Once the wood frame on this Cord is repaired and restored, the rear sheetmetal can be reattached with nails and screws.
All of the wood framing on the cab of this 1930 REO Speedwagon had to be replaced.
Note the nails used to attach the metal frame to the roof rails. A small gap is not a big deal, since a metal angle holds the frame together at the corners.
Note the wood flooring and recessed holes for bolting the body to the metal frame rails.
The old floorboard on this REO was too far gone to restore, so a new piece was put in its place, scribed to fit around the steering column.
Once a replacement piece is cut with a band saw, sanding by hand and on a belt (or disc) sander can provide the final shaping to fit.
Paint can applied to match the original color of the frame. Here, Van Steyn is comparing gloss and flat paint colors to see which is closer to original.