FINISHING YOUR WOODIE, CHOICES, PROCEDURE AND STYLE
by RICK MACK
I learned everything that follows in this updated ‘how-to’ dissertation from hands-on experience, trial and error, and experimentation. I have been working on woodies since the fall of 1961, a length of time that is hard for me to even imagine.
Restoration of a woodie must necessarily begin as a contemplative experience. Each of us must spend a good deal of time just staring at our woodie, absorbed and thinking, trying to figure out just how some aspect of the project should look...sound...feel...or proceed. Most of you already know what I mean. This think and dream time---hard to separate the two---is an integral part of the fun, and the work, but it also can be very frustrating at times, especially when making our own final choices and decisions. Hopefully, the following information will help to make your finishing choices and experiences at least somewhat easier.
Choosing the right finish for your woodie depends on several important considerations: Is your woodie being restored to original? Will your woodie be shown and judged for points on its originality? Perhaps it will be a “driver” or a “street rod”? Do you have small children? Dogs? Where do you live? California? Alaska? North Dakota? How ‘bout the Gobi Desert? Do you like “super shiny”? Do you have access to spray facilities? What is your vision for your woodie? There is a lot to consider.
What are the choices for finishes?
VARNISH
My favorite finish.
In the beginning there was varnish. An excellent and ancient (Stradivarius mixed his own!), tough, reliable and, most important, EASY to apply wood finish. Varnish flows out so smooth all by itself. You can brush it, spray it, or rub it on with a rag. It is very adaptable and beautifully lustrous after six, eight or even more coats. Anyone can use it and apply it at home, but it does take time, especially the thorough sanding between coats. Ford, GM, Chrysler and every other company that originally produced woodies used varnish as their primary finishing material. Varnish was simply the best product available for exterior finishing during the twenties, thirties and forties, even into the fifties and sixties. Good stuff then, good stuff now.
[I believe that all the automotive manufacturers used specially formulated varnish, which was used with a catalyst to facilitate faster drying and shorter application times]
Varnish basically comes in GLOSS and SATIN. Woodies were varnished in gloss from the factories. There are woodies that still have their original varnish today and sometimes this varnish appears to be satin, but that most likely is due to the ‘dulling’ effects of age rather than by choice.
The only real drawback to varnish was DURABILITY or the lack of it, especially with the earlier formulas. As all woodie owners who had to drive their cars regularly have experienced, varnish deteriorates under sun, rain and abrasion resulting in cracking, splitting and peeling of the finish, leaving areas of the wood unprotected. This did not happen overnight but was inevitable over a long period. A woodie kept in daily use with a varnish finish will need to have a sanding and revarnish job every year or two to stay sharp. This constant maintenance problem was just one of the reasons for the ultimate demise of the woodie as a production car. These wood wagons were also difficult and expensive to produce as well, but the buying public’s inability and/or unwillingness to keep sanding and varnishing the wood always held sales down---especially after the steel bodied wagons appeared!
Much has changed since the days when woodies were production cars. Varnish, for one, has improved greatly, now having excellent ultra-violet, UV, protection and much more durable formulations, translating into much greater longevity. Modern varnish makes a wonderful finish. Probably the greatest difference between ‘then’ and ‘now’ is the simple fact that, today, few woodies are used as all-weather daily drivers! All things considered; modern varnish makes an excellent choice for your pampered woodie.
Many fine brands of varnish are on the shelf. I like Z-SPAR FLAGSHIP and EPIPHANES for their great UV protection. I like Z-SPAR CAPTAINS and INTERLUX SCHOONER for their wonderful warm, golden tone, and these also have good UV protection. Always read the instructions of the brand you choose. Also make sure that you have the correct thinner to match the varnish. It is best to buy varnish by the quart. The gallon is less expensive, but it will “skim over” and become useless long before you get to the bottom of the big can!
Applying varnish can be a very enjoyable, Zen experience! We’ll get to that soon.
URETHANES
Basically, these are automotive clear-coats and they are REALLY TOUGH! They do require a catalyst, they must be sprayed, and they can be TOXIC! You will need a ventilated spray booth, quality respirator and an inexpensive spray suit would be advisable as well. If you have access to proper spray facilities, you can quickly spray a very durable finish on your wood, and it is possible spray THREE coats in a short time without any sanding in between. Urethane glosses out like polished glass, dries very fast, and cures out in a few days as hard as nails. Flex agents are also available as additives to urethanes and is probably a good idea to use them due to wood being a natural material that expands and contracts with moisture and temperature. All automotive paint companies produce a catalyzed urethane for clear coats. No tougher or more glossy finish is available! However, because of the high VOC and toxic nature of this material, it is not for everyone, and it is not readily available in California. At least it is not supposed to be. Check with your local auto paint store or local body shop. Oh yes, this is real high-tech stuff, and you MUST follow the manufacturer’s instructions precisely! Urethanes are NOT ZEN!
NOTE: At this point, I need to add some caveats to the use of automotive catalyzed urethans. My long-term experience has shown these finishes do not do well when applied directly to wood. Even when used over a catalyzed epoxy sealer. The material tends to begin to peel over time, usually starting near a joint, and once it starts to peel, it is impossible to stop the process from continuing. The urethane loses its ability to stick directly to wood. A more practical and effective way to use this finish is to apply it as a ‘topcoat’ over several coats of properly applied traditional varnish, which strongly adheres to wood. I recommend first applying five or six coats of varnish, then two or three coats of catalyzed urethane sprayed over that varnish. The clear urethane will absolutely stick to the varnish and will not peel. This finish will last. It will be bullet-proof, and high gloss. The fact that the urethane is very fast drying also minimizes the amount of dust that might settle on the final topcoat of slow drying varnish. Let your varnish fully cure for a week or two before carefully water sanding with 600 grit to prep the varnished surface for the urethane finish. Don’t load the urethane on in a flood coat over the varnish. Use thin coats.
OTHER CHOICES
I understand that some similar finishing materials are now available in “water-base” but I have no experience to date with any of these products. Eventually, all finishes will have to be water-based and environmentally friendly. A very good idea, especially if these products can be made to be as tough as the solvent-based finishes of which I am familiar. Time will tell.
There is another class of finishes known as POLYURETHANES. They are readily available at all hardware stores; they apply with a brush or spray very similar to varnish products, but they are different chemically from the varnishes. Some are water-based too. They are very durable and easy to apply, however, they usually do not have any color tone. Polyurethanes are very clear; some even have a slightly cold or blue cast to them which I find unsightly on wood. I much prefer the appearance of varnish but if you are looking for a super clear finish that can be applied with a brush at home, polyurethane may be for you. If you are going to use polyurethanes, you can follow the same instructions below for sanding and applying varnish.
WOOD PREPARATION, GOOD WORDS, MEDITATION AND SANDING
No matter which finishing material you choose for your woodie, you will need to sand the wood thoroughly before applying the finish. This process is always the same, today as yesterday, no short cuts. For new wood or old wood in GOOD CONDITION, use a random orbital sander (Dewalt makes the best, you can’t miss ‘em, they are yellow!). Start with 80 grit to get out any heavy scratches or dings and to get off the dark, weathered top layer of the wood. These darker areas usually occur in patches where the varnish has worn off, but on some wagons, there is no finish remaining at all. All the wood is darkened. Wear a dust mask! After the 80 grit, move on to sanding all the wood again with 100 grit which gets rid of the scratches left by the heavy 80 grit, then sand all again with 150 grit to remove scratches left by the 100 grit. In most cases, sanding down to 150 grit is more than adequate. Maybe sand down to 180 grit if you are obsessive. Further sanding with finer sandpaper on hardwood becomes an exercise in futility and can sand the wood so much that it has no “tooth” to hold the finish! Yes, some people insist on sanding to 220 grit, which is the maximum I would sand to. You should dust off the wood between sanding grits so no errant pieces of sand from the previous grit will remain to put those nasty little circular scratches into your wood.
You must be sure to look very carefully for any remnant heavy scratches, they will appear under good light after you have finished sanding with 150 grit. If you do not find them and re-sand them out now, they will surely be visible after you have applied the finish. Take your time here. You will need to do some sanding by hand each time to get into the grooves and corners.
If you need to bleach your old wood, do your full regimen of sanding first! After bleaching, you can only sand lightly with 180 grit or 220 grit by hand to smooth out the fuzz raised by the bleaching process. The bleached layer of the wood is not very deep, and it sands off easily. Read more about wood bleach in my separate instructions for wood bleaching.
When sanding softwoods such as the mahogany panels, you will need to sand down to 220 grit. If you plan to stain your mahogany panels the extra fine sanding will assure that there will be no tiny swirl marks left to trap the stain and look ugly under the varnish. Remember: paneling veneer is very thin. Be careful not to sand through it! Take the panels out in the sun, you need really good light, to view the wood closely to see any large scratches that need to be removed with the fine sandpaper before varnishing.
After sanding thoroughly through the grits with the random orbital sander, take some 180 grit or 220 grit sandpaper in your hand, maybe use a solid rubber block with the sandpaper, and smooth out the edges and corners of the hardwood and the difficult to reach inside corners. note: Varnish or any other finish will NOT stick well to a blade edge. Always ease all the edges at least a little! Yes, it is best to sand “with the grain” but you knew that.
Your new wood and old wood should now be ready for application of the finish. Note: You may need to bleach the wood before finishing, especially if there are still darker patches. See my separate instructions for bleaching wood.
One exception: If you have bleached any of your wood, it most likely will need to have some toning done as the A&B type wood bleaches tend to leave the wood looking more like bleached bone found on the desert than warm maple, birch or ash.
Here is how to tone the wood.
Go to your local art store and buy some oil-based artists paint tubes. I use “raw sienna” with a little “burnt sienna” stirred up in a mix of 1/3 mineral spirits, 1/3 PURE-BOILED linseed oil and 1/3 lacquer thinner in a quart container. Squeeze a couple of toothpaste globs of the raw sienna into the mix and then a small squeeze of the burnt sienna, just a little now, put on the top and shake it up. Mix it very thoroughly. You will have to shake it up periodically during use as the color settles out quickly. Keep handy another cup of the same thinner mix without any color added. Mix some of the colored mix with some of the clear thinner mix and apply with a brush
to some of your bleached wood. Let it sit and soak for a few minutes then wipe it off with a clean rag. Try a thin mix first and add more color to the mix if you need it. Remember: THIS IS ART, NOT SCIENCE! With some practice and experimentation, you should be able to match the color of the bleached old wood with the color of the new wood. You can do this so well that old and new woods will be indistinguishable from one another! Note: Nothing can be done about weather-checking cracks or dry rot. These injuries are permanent unless you replace the wood pieces with this type of damage. Always try a test piece of wood first and let the stain/toner dry for at least a couple of days before applying your finish.
Another option for adding tone to your wood is SHELLAC. This is a natural finishing material that comes in “blond” and “amber” tones right off the shelf. It makes a wonderful sealer under varnish and even catalyzed urethane if IT DOES NOT HAVE ANY WAX in it. Read the labels. You want it WAX FREE. The amber tone is very warm, again experiment.
You can also use toning to selectively match new and old wood pieces. I recommend Zinsser ‘Bull’s Eye’ Shellac. It comes in a yellow can and is available everywhere. No wax. I usually mix about 1/4 of amber shellac with 3/4 of clear shellac. I also thin the mix maybe 15% with denatured alcohol so it will soak way into the wood. Do not use it under the POLYURETHANES!
If you wish to stain your mahogany paneling, there are a myriad of commercial stains available at your hardware or paint store. I have used many different brands, both water-based and solvent-based, most have worked very well. Pick a stain and try a test where it will not show. You might have to mix two stains together to achieve your desired color. Experiment!
A trick.
If you only want to darken your mahogany slightly, try setting all of your paneling out in the sun for an hour. Be sure to evenly expose all pieces as any shaded area will remain lighter! This process works be itself in your shop if you leave the paneling exposed to light or even air for a long time. Keep it wrapped up until you are going to work on it. Once a finish has been applied, the paneling will no longer darken in the sun.
This only works with wood that has a tone. It is because darker wood contains tannins. It is the tannins that darken when exposed to bright light. Maple and other light woods do not have any appreciable tannins.
ARE YOU READY? LET’S TRY VARNISH. YOU’LL NEED GOOD LIGHT!
Start with a 1-1/2” brush. It can be an inexpensive one since we are going to first be applying varnish coats to obtain a “build”, meaning some thickness of coats on the wood before we worry about sanding it smooth. You can use a throw-away “sponge” brush on the flat paneling, and sponge brushes do work on the structural wood parts as well. Buy the sponge brushes with the solid wood handles, not the plastic handles. Pour some varnish from your quart can into a separate cup. Estimate how much you are going to use. Never varnish directly from the can as doing so will quickly contaminate your remaining varnish with “crud’ known as “inclusion bodies” which will lump up your subsequent coats. If you have varnish left over in the cup when you are done finishing for today, paint it on the doghouse or maybe on the hidden areas of your wood or on the backside of your paneling... Don’t pour it back in the can! As you work your way through a varnish can, you may need to use a paper filter when pouring the varnish into a container for application. Even the quart cans can often skim over when they are half empty. You don’t want lumps.
Before you start varnishing, it is a very good idea to clean off all of the wood that you have carefully laid out to varnish. Try using a soft dust brush first then a vacuum cleaner or air blower (Blowing the wood dust around can be a problem however), then wipe with a cotton rag dampened with paint thinner, let dry and, finally, go over the wood completely with a tack cloth. The cleaner you can get the wood, the better the varnish job will be!
There are at least two different theories about the first varnish coat.
I feel that the first coat should be thinned as much as 50% with the appropriate thinner for the varnish that you have chosen. Read the labels on the can regarding thinners. The theory is that the first coat will soak way into the wood---be especially thorough wetting the open-end grain to seal it against moisture. (Some woodie manufacturers actually soaked the wood in varnish to seal it!
Some manufacturers did not varnish the ends or back sides at all.)
Another theory is to use the varnish straight from the can without thinning. Perhaps reading the instructions on the can is the best way to go about this. Most brands recommend thinning about 20% on the first coat.
If you have already used a thinned shellac for toning, that will be sufficient to seal the wood before varnishing. You can start your varnishing with varnish that is only thinned enough to allow for easy brush strokes. All further coats should be only thinned enough for easy brushing, and this really depends on air temperature. Varnish works best at about 65 degrees, without thinning. If you are varnishing at 85 degrees, you will need to add more thinner to the mix.
With my 1-1/2” brush, I apply a 50/50 thinned mix of varnish, working quickly to get the wood thoroughly coated. Work a single piece of wood or a single unit such as a door at one time so you can be thorough and maintain control. After you become adept at varnishing you can work larger areas or multiple units. You may brush cross-grain or any way you choose to quickly get the varnish onto the wood and once it is completely wet, shift to brushing out the varnish WITH THE GRAIN so it will flow out smoothly. Thoroughly saturate the end grains with this thin coat!
If you are working on an assembled unit such as a door, pick a piece of wood at the top, varnish it completely, stroke it out with the grain then move on to the next attached piece of wood and follow the same procedure. Try to keep a “wet edge” when varnishing, not letting the varnish dry before continuing from the last point with new varnish. This takes a little practice as you must move down a door in several directions at the same time. This is why you will need to work quickly. However, varnish is really forgiving, and multiple coats will cover any missed spots. Try NOT to leave too many missed spots during each coat. After a couple of coats, you will gain more control and find your own rhythm and style of applying varnish.
Moving on.
After you have varnished your ready wood pieces with the 50/50 thinned mix, let the varnish dry for eight or ten hours then go right back and apply a second coat of the same thinned mix. As long as you do not wait any longer in between the first and second coat, the second coat will stick just fine. If you wait a day, you will need to sand lightly with 220 grit or a scotch pad so the next coat will stick. Let the second coat dry completely, perhaps taking two days. Now sand LIGHTLY with 220 grit and follow up with a scotch pad to completely dull the surface for the next coat to stick. These two thinned coats of varnish are not yet thick enough to sand aggressively.
[Alternative: I find that when using Z-Spar Captains Varnish (and other brands as well), I can apply a coat in the morning, wait about four to six hours, apply a second coat, let dry overnight, come back in the morning and apply a third coat, then let dry completely, then sand lightly. You can do this at least a couple of times to speed up your build coats. After six coats, you can apply a coat, wait four to six hours, apply the second coat. Let dry, sand thoroughly, then apply one finish coat at a time, sanding and prepping with 600 grit in between, until you are happy with the final finish.]
Clean the sanded surface with a thinner rag, then a tack cloth and mix up a third coat of varnish. This time you need to mix 25% thinner with 75% varnish. Do read the instructions on the can regarding just what to use as a proper thinner for your selected varnish. Apply a third coat of the 75/25 varnish/thinner mix and let dry completely. Scuff thoroughly with a scotch pad, clean the wood and apply a fourth coat of the 75/25 mix. Let it dry completely. Scuff this fourth coat thoroughly with the scotch pad.
For the fifth coat and for subsequent coats, you want to thin the varnish 10% to 20% depending on the ambient temperature. You can use varnish at full strength here, but it will not flow well if the weather is too warm. When your brush “drags”, you need to thin your varnish. Varnishing is a matter of “feel” and varies from person to person.
After you have five or six coats of varnish on your wood, you can begin to sand more aggressively with 320 or 400 grit sandpaper between coats. Be careful of sanding too much on the edges as it is easy to sand through to bare wood. It is a good idea to avoid sanding the edges with sandpaper and just touch them lightly with a scotch pad to give them a “tooth”. The more coats you have, the cleaner you need to get your wood before applying the next coat of varnish. When you have successfully applied seven or eight coats, you are ready to apply a “last” coat. Wipe that wood clean and apply a last coat thinned at about 15%. When dry, check it out. How does it look? did you get a lot of junk in it? You can sand out a few lumps with 600-1000 grit wet and dry sandpaper, then rub it out with polish but if this coat has too many “inclusion bodies”, you will need to sand and apply another “final” coat. Dust is always your enemy with slow drying varnish. Use your best brush on these last coats and clean them after use with lots of mineral spirits/paint thinner but NOT lacquer thinner.
[Alternative: use the wooden handled sponge brushes and throw them away when you finish each day]
Much of this varnish work is a learning experience and requires some getting used to before finding your own rhythm and style. Deciding on when the job is done is kind of a judgement call as well. You are done when you are satisfied that the varnish looks good and feels good to you. You can always Sand and polish a few bumpy spots.
There are other approaches to thinning, to sanding and to varnishing. I have one friend who always uses varnish straight from the can without thinning at all! He does put it into a separate cup before applying. He also sands solely with 150 grit in between coats, a grit which seems a little too rough for my tastes but his varnish work is always superb! Another friend, who restores wooden boats, only uses EPIPHANES varnish and thins the first few coats 50/50 then applies some at 60/40 then some at 75/25 until he reaches 16 or 18 coats-all with a sponge brush! His boats are spectacular! These differences in procedures and approaches are really a tribute to just how versatile and forgiving varnish is! You will have to find a varnish regimen that works for you.
The final varnish coats can be sprayed of course, for that matter, all of the varnish coats can be sprayed. I feel that the beginning coats are easier to control with a brush during application. The brush also allows you to fully saturate and better seal the end grains of the wood.
Varnish dries slowly so it sticks to everything when sprayed.
APPLYING THE NOT-ZEN, HIGH-TECH STUFF: URETHANES
Update:
I no longer recommend applying catalyzed urethanes directly to wood. I no longer recommend using Smith’s Catalyzed Epoxy Sealer either. I now would only apply these high-tech automotive finishes over several coats of traditional varnish as a good, and permanent base coat. Varnish sticks to wood! Urethane sticks to varnish!
When choosing to use catalyzed urethane as a topcoat over varnish, follow the same prep procedures as you would do before applying a subsequent coat of varnish: thorough sanding with 600 grit wet and dry sandpaper. After sand, and thoroughly dusting off the wood, it should be moved into a suitable spray booth and tacked off again.
Following the manufacturer’s instructions exactly, mix the URETHANE that you have chosen. Mix only as much as you think you will need, perhaps a pint or a quart. This material IS expensive!
Note: Urethane is ABSOLUTELY CLEAR. NO TONE. If you wish to have your wood appear warm and golden like it does with a varnish finish, you will need to tone the urethane with DMX dyes which are available through your local auto paint stores. These dyes are known as “RADIANCE” colors at the auto paint store. You only need a small amount of DMX #212 RED and DMX YELLOW (They only make ONE yellow). Take your own little bottles with good, tight tops to the paint store. You will need no more than an ounce of each color. The DMX RED is more intense than the DMX YELLOW.
Try a mix of one drop of red and four drops of yellow to each pint of your clear urethane. Use a SMALL drop dropper, not a BIG drop dropper! Drops can vary greatly in size, try to standardize the drop size. Add more color if you need it. Do a test first on some scrap wood. TEST, TEST, TEST!
If you are applying urethane clear over several coats of varnish, there should be more than enough tone in the varnish coats. It is not necessary to add tone to the clear.
Put on your respirator, go into the booth, load your spray gun with your mixed urethane and spray on three coats of the urethane, waiting about 15 minutes in between coats for the clear to “flash”.
Good idea to first check with the brand manufacturer’s instructions on proper application!
Three coats of urethane over the top of maybe six base coats of varnish should give you a glass -smooth finish that will last for many years.
You can always sand and buff out small aberrations or dust.
The soft mahogany might need an extra three base coats of varnish as it is very absorbent. Whether you choose to use automotive urethane over varnish or varnish all the way on the paneling, you will need more coats. After the last coats, varnish or urethane are dry, you can sand out a few “inclusion bodies” with 1000 grit or 1500 grit and then polish out the wood with fine polishing compound. This final step takes some time but can make for a super smooth and glossy finish-just like a custom paint job! Yes, varnish can also be polished out in the same fashion as urethane, but it takes longer to cure before it can be successfully polished, or hand rubbed out.
If you are unfamiliar with spraying automotive paints, you should seek some professional help or choose to use brushed on varnish as a finish. The urethane finish is super tough and glossy but it IS high tech and requires some advanced knowledge to use properly.
One of the above methods of finishing should work for you. It is not a bad idea to find some wood to practice on before you start on your woodie. Good luck and good finishing!
PANELING
Some thoughts about paneling.
Replacement ‘flat’ paneling is available in several forms. You can often purchase commercially produced 4’x8’ sheets of mahogany paneling, as well as other species, from full- service lumber yards. These sheets come in different thicknesses, 1/4”, 3/8”, 1/2” and so on. You will need a jig saw of some sort to cut these sheets into the various sizes to fit your car. Use the old panels as patterns. Work carefully. You will only have the choices for what the lumber yard has ‘on their shelf.’
There are companies that will press up custom paneling on special order, but they do charge for that service, and the paneling will be shipped in 4’x8’ sheets, which also runs into some added expense. A Google search should turn up a few names for these companies.
At my shop, I utilize a vacuum pressing system to ‘layup’ all my own paneling using select veneer that is available from specialty veneer companies. This is required for all the 1949 through 1951 Ford and Mercury wood paneling as these are all curved panels, not flat. On occasion, I also press up special veneer for flat paneling as well.
When it comes to finishing, keep in mind that the veneer on the surface is rather thin, and it is easy to sand through the veneer if you are not careful. Same goes for rough handling of the panels, you can easily damage the veneer. Soft wood will require more coats of varnish. Production paneling usually comes sanded to about 120 grit, so fortunately, not much prep sanding will be necessary.
STRIPPING THE OLD FINISH
This is the messy part of the project. I started out doing this in the alley besides our family home in Sherman Oaks, California. That dead end alley became my first and only woodie shop throughout the 1960s. This is where I learned and relearned it all.
If the car still has varnish on it, or even a coat of old paint, it will need to be totally removed before you can proceed to the various stages of refinishing.
If you are not going to disassemble the wood on the car, and I would usually recommend that you do at least a partial disassembly, it is possible to strip off the old finish using paint remover. There are several brands on the shelf. I have no preference, but I would stay away from the orange, environmentally safer remover because it will require washing all of it off with water. It does not dry like the solvent based removers. Staying wet is very hard to control. Very messy. No way to clean it up.
Note: Good idea to first do a full tape off and masking of all your fenders so you don’t ruin your paint!
You must be very careful with chemical remover. Most brands burn your skin, so wear rubber gloves or suffer the effects. Don’t get it in your eyes! Use throw-away brushes to apply the paint/varnish remover. You will also need some flat scrapers, plastic ones are probably best, but you can use metal ones if you are careful---metal can quickly dig into the wood if you are not careful. Small brass wire brushes will help to get into the grooves, cracks and tight corners. Don’t use steel wire brushes, they will deeply scratch your wood.
Work on only one unit at a time, maybe the door or the quarter panel. Pick a place to practice first. When you get the hang of it, you can start working on a wider number/area of parts. You will need to apply the remover more than once; one coat and one scrape is never enough to get all the varnish off. Maybe even three coats will be needed in some difficult places. Apply, scrape, brush, repeat. Eventually all the wood will be totally free of old varnish---the entire woodie will be free of old varnish.
Then comes the sanding phase. You are going to find that some areas are darker, and splotchy, this is where the old varnish completely wore off and the wood was exposed to rain and sun for who know how long. You will need to sand these areas thoroughly, sometimes with a course disc sander, and then even out the sanding with a random orbital sander using ever finer grits.
Once you get all the old finish removed, and the wood sanded and clean, you will probably need to beach the wood, especially where the darker blotchy areas are. If you do not bleach, those areas will be much darker than the surrounding wood when you varnish.
Most often, but not always, the interior of the car will have far less weathering, and may only need some soap and water cleanup, and maybe a fresh coat of varnish. If the interior is also really rough, the same process used on the exterior will be necessary to use on the interior. Oy vey! That is a much more intensive experience. You will have to work overhead with the chemical strippers, and the scrapers, and the wire brushes and sanders.
Should the car need interior stripping, it may very well be easier to disassemble the wagon, at least take the top off so you can work on it separately and upside down. This is a much larger project, and not for the beginner, at least it requires more information than I can provide here.
For more information about wood kits for 1949 – 1951 Fords contact Rick Mack at rickmack.com.