I’m going to talk to you about a controversial but interesting part of American automotive history that is seldom talked about. We often drool over engine specs, maybe car design, but no one really ever talks about chemicals and what that really means to the average man or woman. What were the chemicals used in automotive paints throughout the 20th century, and what does that have to do with working at the car wash blues?For starters I myself am a new automotive painter and bodyman. I went to my local trade high school where I majored in auto body, and from their I went onto to Nashua Community College in New Hampshire where I participated in the Associates Degree program for collision repair. I was motivated to enter this industry and help others because of the sketchy repair shops out there that would deceive you to make a dollar.
I was getting frustrated with my own classic car collection. When I was in high school I paid a bodyshop to spray my 1974 Mercedes 240D with clear coat. After years of driving it the paint started to fail, and I said to myself I could do a better job. So that is the career choice I moved towards. Today I am constantly learning new things every day, and today I want to share with you why I feel the industry has moved away from quality paint jobs. This is purely my own selfless opinion and if you disagree with it, thanks for reading. This world is full of opinions. This is why I believe that there is nothing more that beats a single stage paint jobs of the past.
Beginning Of Automotive Paints:
In the beginning there were cars, and cars created smog and expensive repair bills. However one interesting aspect about automotive history that is seldom talked about is the history of industrial paint. The first automotive paints were nitrocellulose lacquer like what are still used today to paint guitars. Brands such as Dupont 44S, Lucite, Delux, and Duracryl. They produced vibrant colors. They were originally painted on with brushes made of badger hair bristles. This method of painting was popular throughout the early half of the 20th century. After WWII air compressors started becoming more popular as more shops could afford them, and we introduced the siphon feed gun. This is when metallic based alkyd and acrylic enamels gained popularity in the 1940’s that that dried by a chemical reaction rather than waiting to air dry. We can remember Centarui, Delstar, Chief, Wizard, Marble, Effecto, and BPS. By the way these brands were all American companies. Today PPG is the only domestic company left that is selling paint lines to bodyshops.
Commenter Bill Wilson below pointed out that Henry Ford had his labs developed a synthetic enamel made with soy bean oil in an attempt to help out US farmers during the Depression. The US went to war with most everything painted with synthetic enamels with the vehicles, halftracks and tanks carrying a touch-up kit of paint and small brushes that were cleaned in gasoline. Part of their daily maintenance was to touch-up their paint job to prevent rusting. The white stars and letters were touched-up by the repair crews since that was a special paint that detected poison gases by turning shades of pink. The stars were made large so crewmen and foot soldiers could see their color change thru vision ports and from a distance. Fore most of our country’s history it was single stage paints we relied on for industrial use and still use to this day in industrial applications.
These older paints were in fact more durable than the paints we are using on modern cars today because they contained a catalyst, which means they had a chemical structure. In other words they dried through a chemical reaction rather than mechanically by air. These paints could not scratch, they could not peel, they could not chip, and they went on in three or sometimes four layers or even way more. Single stage in fact means you have more quality pigment on your car. The pigment defined your car. How do I know it was scratch proof? Scratching layers of paint off the car is how you brought back the shine of the car. That is why wool pads used to be the norm. The more you scratched off the more your paint would shine. This is where I will bring up the car wash as an example. Today they tell you not to bring your car through the car wash, they say a car wash will destroy your car and eat away at the paint. That used to be the point.
The old windmills worked by stripping off old layers of oxidized paint, so every time you would bring your car to the car wash it would come out looking glossier and cleaner every time. Zero scratches. It was like a giant buffing wheel that would make any paint shine like new. Starting in the year 1994 these windmill car washes were phased out for touch-less jets because the industry made the move away from single stage to bc/cc.
Even lacquer paints were immune to scratching and peeling because they too were one chemical structure. Even though they contained no catalyst. They may have faded more easily than enamel but they were a stable structure. The first clears were made of lacquer. So you had a chemically bonded structure as the pigment with UV protection, and an outer shell that was mechanically bonded by air so it never truly cured. Which means that in the days of lacquer clears if you nicked your car you could melt it back in with a rattle can. In other words it was very easy to maintain.
They were also more cosmetically pleasing not only because they did not suffer from scratches, but also because they did not suffer from excess orange peel like urethane clear coat. When we switched over to gravity feed guns we invented orange peel on cars which I will talk about further down. Let me talk about the beauty of lacquer paints. If you chip your paint job, you can do spot repairs and the paint will melt back into the existing layer. With enamels if you scratch your paint job, you can buff the scratch out without repainting. It is simply a stronger design for your vehicle. You never have to repaint the entire car. With single stage paint the function was designed to last indefinitely. That is why today many restoration enthusiasts still insist on using single stage for their jobs, especially for solid colors.
Three misconceptions I would like to bring up. First is that a single stage paint job will fade in sunlight. This is incorrect. Single stage paint is no different in makeup from clear coat. The only difference is that it is one chemical structure rather than two. There is still UV protection built into single stage paint, and acrylic urethane single stage is very resilient to sun. Lacquer paints will fade if you use your classic as a daily driver but it can be maintained correctly. Also many enamel jobs faded quickly if they were painted at discounts bodyshops like the old Earl Scheib or Maaco who always would leave out the optional hardener. They would get it dry and hard enough to work by air, but it wasn’t chemical resistant or very tough.
The second misconception is that lacquer paints crack. Yes it will crack in cold weather if it is applied in too thick of coats. They will also crack if you use spot putty underneath that is prone to shrinking overtime. Or if your bodywork is not very flat. Or if you used a primer underneath that does not like lacquer. Also if you park it out in the sun every day. Since lacquer is more brittle it is more temperamental to the elements. Nitrocellulose was even more brittle. Some people to this day insist on lacquer for show cars for it’s depth of color since it can be maintained enough for trailer queens. However all single stage will have a greater depth than clear coat.
The third and final misconception is that single stage lacquers and enamels were bad for the environment. The truth is that the urethane paints we use today are far more toxic to both our lungs and environment than the single stage products that were used at the first half of the 20th century. This is because single stage lacquer did not contain a catalyst, which means they contained no isocyanates. This is why we can no longer paint cars out on the shop floor. You actually get worse results in a paint booth. A paint booth is not a sterile environment. You can read up on literature about what breathing in isocyantes does to your lungs. It was once common to see guys painting cars with no masks on in the 50’s and 60’s. Say what you want, they were not breathing in isocyanates that acts like a glue in your lungs. Therefore you cannot say we made the switch because of environmental or health concerns. Lacquer and enamels were much safer to spray.
If you’re going to spray single stage I would also recommend that you get a siphon feed gun and put marbles in the cup which is an old school trick. Siphon guns will allow you to spray upside down too and reach into tighter corners. Your pigment will flow out more consistent, because you have to remember with single stage it is all about pigment dispersion. Gravity feed guns have a tendency to bottleneck like ketchup in a glass bottle. Don’t think you are shooting lacquer or enamel with an HVLP gravity Iwata.
The Switch To BC/CC:
Some time around the early 80’s two new technologies were emerging. There was lacquer clears and then urethane clears hit the market for bodyshops. They were gravity feed spray guns, and a new paint line that would be applied in two parts. A base coat which was your color, and a clear which was supposed to make painting easier. The Mini Cooper would be the last consumer level production car painted with single stage paint from the factory in 2005. Volvo 240 was the second to last European model painted in single stage black which ended in 1993.
Let’s throw away some misconceptions first. The industry did not make the switch because bc/cc is a better product. BC/CC is both more fragile and less attractive to the eye than a single stage job. Likewise a siphon feed spray gun will give you the same quality job as a gravity feed gun if not better. It’s the only way to spray lacquer.
The second misconception is that the industry made the switch because the EPA “made them” do it. In reality there is no federal law that exists banning the use of siphon feed guns. I live in liberal Massachusetts and I can still buy siphon feed guns at my local Walmart. In fact any HVLP gun can simply be taken out of compliance by increasing air pressure. The industry is now even moving towards water based paints. However that is also a sailors tale, because you still are using solvent based clear coat. There really is no difference when it comes to the environment.
The truth is that the industry made the switch because it saves them money. Base can be applied in a single coat. You barely need any pigment product, because the clear coat will do all of the work for you. Water based paint simply makes it supposedly easier to match, but that’s only because insurance companies don’t give painters enough time to blend. Number two is that a gravity feed gun cuts down on materials used that both saves bodyshops money and produces less VOC’s which makes the EPA happy. It’s considered a win-win for men in black suits and the workers bought it up.
However there are many drawbacks to what happened. First is that by switching to a gravity feed spray gun, single stage metallic could no longer be sprayed. Gravity feed guns do not flow out the metallic evenly. You really can’t spray single stage metallic with a gravity feed HVLP. So by switching to base coat and clearcoat the pigment was no longer the showcase. You no longer had to spray out a perfect job. This not only saved the shop money but it was “better” for the environment. To get the same quality job out of single stage would take four to five coats plus higher pressure, where as the new system required one or two coats and you are done.
With base coat any imperfection in the pigment will be less noticeable if not unnoticeable unless you are spraying silver metallic which is just a terrible color for any system any day of the week. However I am not the only one who believes it takes more skill to shoot a single stage solid color and get a good finish than it does to shoot a bc/cc metallic or pearl. However this cost savings and easier application has its tradeoffs. You are trading quality for convenience. That is really the only reason the industry switched.
You see a clear coat is like a second color on top of urethane pigment. They call it clear coat but it is not really clear. It’s actually slightly yellow. It does have a cloudiness to it, and this fogging is noticeable even in the best clears. Today’s cars are not as vibrant as they used to be and it’s noticeable. It’s not just cosmetically inferior either, it’s durability is inferior as well. Clear coat is more fragile to handle and base coat is an inferior weaker pigment. Proof of that would be if you did not use clear coat over base coat, the base coat would fade within days. There is no UV protection built into base coat unlike in single stage. The UV protection is in the clear coat, and one of the problems clear coats have is they are prone to “hairline scratches” which opened up a new money making scheme.
What happens is eventually the owner wants their car to look nice again. You often send it off to get “detailed” to remove those scratches. Your detail shop will very gladly take your money and lots of it to make your car “look nice”. You will gaze at that mirror finish and believe you got your money’s worth. Then you are told to buff and apply wax to your car every year to protect it from the sun. This could not be a bigger misconception about modern paints. This is simply not even close to the truth, and by taking care of your paint on a modern vehicle are you actually causing more damage?
The truth is, every time you buff scratches away you are removing layers of the UV protection no matter how expensive the clear coat was. This is because the UV protection comes from orange peel. Cars from the factory are purposely painted with lots of orange peel for this very reason. Some I have had this debate with have been quick to point out that single stage paints can scratch too, and that is very true but there is a difference. If a single stage paint job scratches it can be repaired without repainting. Once your clear coat becomes scratched there is only so much sanding and buffing you can do before it makes your clear too thin. The nature of clear coat only allow you to build up your material so thick so you only have one or two layers of protection, versus four or five coats of enamel or urethane.
However if you ever needed any repairs on your vehicles you have to factor in that bodyshops have switched to gravity feed guns, and today many are using 4:1 clears. You want your clear to be at least 2.5 mils thick to provide adequate protection from the sun. Two coats of clear with 1.2–1.3 mm fluid tip on an HVLP gun will just get you in the ballpark of thick enough. However now you’re taking that down with a buffing wheel. It just won’t last, and especially how conservative shops run these days on cost of materials you don’t have much room to work with. If you own a classic car you restored this is bad news. A restoration shop often tries to give you a mirror or glass finish from the start. In other words a restoration shop buffs away the good orange peel. Therefore if you own a show car with clear coat and you are constantly wet sanding and buffing away at it each year, chances are you have very little UV protection left. If you insist on using clear I would recommend at most three coats. However the more durability you have with clear coat the more clarity you sacrifice, and put on too thick and you risk problems. So that is the real catch 22 about modern paints.
Overtime after being exposed to buffing, sunlight, acid rain, and salt from the roads the clear coat will breakdown and get thinner overtime. Especially these days the clear coming from the factory is applied by robots very conservatively. Since base coat is not a catalyst structure like single stage it will get chalky if exposed to sunlight, and then your clear will have nothing left to grip to as it breaks down from the outside elements. Clear coat fails by peeling apart as it separates in two because they are two separate chemical structures, so they don’t chemically bond to each other. When this happens you have to repaint the entire car. Below is a 1999 Accord that was donated to my local college. The owner gave it away before they even bothered to repaint. In essence we have created a throw away culture.
The average driver on the road will not care, because they will likely trade in their vehicle for a new car before the paint fails. It’s also a win for the average driver because the car really never has to be buffed because it’s the clear coat that gives the car it’s shine, not the pigment underneath. You only buff a car these days to remove scratches which I believe you should never do to begin with. Buffing equates to more damage. That is why I recommend that if you do own a collector with clear and want it to last, never buff your car at all. Only buff your car if it was painted with single stage paint. You are really destroying your paint every time you wax it.
Another common mistake that many car enthusiasts are seeking out are painting clear coat over single stage paint jobs, or mixing clear in with the last coat of a single stage paint job. That in the very sense of the word is sort of defeating the purpose of the benefits of single stage. Clear does not oxidize like single stage, so if you do have spots where you burned through or a really thin section you will always have a dull spot. If you used no clear, the single stage paint would oxidize all at once and you could sand it uniformly to bring back the shine. The only way to have a uniform gloss if clear coat was used is to reclear the entire panel or car. Otherwise no matter how hard you try, you would always have dull spot where the color oxidizes with no clear to protect it. Plus hairline scratches. Single stage will never have as much gloss as clear. You can only sand or rub old paint if a clear coat was not used. It won’t totally fail like base coat but the same rules still apply for a difference in appearance.
The final point I will address about clear coat is how toxic it really is for anyone to be spraying it. As I mentioned above unlike single stage lacquer, these modern two part or sometimes three part paints contain catalysts such as isocyanates. Clear coat is so dangerous that half face respirators don’t work anymore to filter out the paint fumes today. In the bodyshop I have worked at, I have seen many young painters with COPD who believe a half face respirator and goggles are protecting them. Not only do you inhale isocyanates, it will be absorbed through your clothing and eyes and hair. Any painter in the modern age who does not want to develop lung cancer should get a full face supplied air respirator along with Tyvek waterproof painting suits. You did not need any of those things with the lacquer and alkyd enamel paints of the past.
Even single stage urethane does contain isocyanates. However for the non professional it does say on 3M’s own website that their P100 carbon cartridges do filter out isocyanates, but they cannot be worn with facial hair and works better in a professional spray booth. The half face masks are simply a pain to fit correctly every time, so I ended up purchasing a battery powered supplied air mask for $800. It was worth my piece of mind. However it’s so important that you do not let modern paints touch your skin or hair or shoes. Cover up like a mummy even if you do get laughs.
“OSHA has clarified its position on this issue in a letter dated July 18, 2000, in- dicating that air-purifying respirators may be used if all requirements of 1910.134 are met and other potential hazards are addressed.”
The fastest way for modern paints to do harm to you is through your clothes, hair, eyes, and hands. Make sure to buy some thick nitrile gloves. If you paint outside you also have access to more ventilation if you don’t have a professional booth. I laugh, but some of the best paint jobs I have seen were painted outside in the fresh air. It’s actually more dusty in a paint booth because in all reality a car should really not be painted close to a dusty wall surface. Paint booths just make the EPA happy.
My Take / Opinion
Don’t believe that modern paint is a superior product. In reality the industry loves saving money in an automotive world dominated by insurance companies. In a production shop it is always about quantity over quality. There is a good reason commercial planes, trains, ships, and even many trucks are still painted in single stage products.
There is a very good reason that single stage paint is still used on anything industrial. BC/CC is simply inferior in durability and appearance. Yes modern paints require much less maintenance, yes it is easier to spray, and yes it will save you money. However if you truly want a paint job that you are not going to see fade with scratches as soon as you put a car cover over it, then single stage urethane is the way to go for the classic car enthusiast.
As part of my car series this month I asked readers to write in and showcase their original paint jobs. This is what they had to share.
“43 years. Original paint from the factory. — Bud Lopez (Monterey, CA)
“46 year old job. She is an original survivor.” — Dan Howe (Charolette, MI)
“I painted this 40+ yrs ago with Dupont Dulux enamel. It’s accumulated its insults over the years but still shines.” — Michael Danihlik (Franklin, WI)
“1968 Lancia Fulvia Coupe Rallye 1.3. All original enamel from factory. It’s my absolute pride and joy.” — Dan Quartarone (Hoschton,GA)
“I repainted her in 1973. White is original to the car except for skirts. Was not a great job either but still presentable.” — John Samulevich (Shickshinny, PA)
“Factory original, 49 year old AMX survivor I’ve owned for twelve years. You’ve got to love AMC.” — Mike Chambliss (Melbourne, FL)
“My dad’s ‘68 KR has the original enamel paint on it, 97k miles on it. Dad bought it in 1981. — Lance Tarnutzer (Lake Mills, WI)
“My 37' Cord, original 20K miles, 2nd owner family. All original lacquer paint and spare tire from the factory.” — Jim McCarthy (Brighton, MI)
I would love to see some of your single stage paint jobs. If you would like to contact me with any questions, my email is firstname.lastname@example.org.