Tag Archives: paint

  • History Timeline and Types of Automotive Paint

    What is the first thing you notice when you see an old car or truck for the first time? If you are like most folks, the answer would likely be the paint. Not just the color but the overall condition of the paint finish. Does it have a beautiful, high-gloss shine or a pleasing, soft “patina” that only the hands of time and exposure to sun and weather can produce? Of course, it is all subjective as we would fully expect a recently completed high-standards restoration to have a flawless, mirror like appearance. Conversely, a car or truck that is 40, 50, 60 years or even older and is still wearing it’s factory applied finish is greatly admired and highly prized for its beauty even though it may be worn through to the primer from many years of being lovingly polished or even proudly displaying some runs or imperfections that it acquired at the hands of that production line painter so many years before.

    In fact, at many show events, an unrestored car or truck wearing its original paint will often command much more attention by admirers than a perfectly restored example. What is all the more remarkable when we admire these old, preserved finishes is the fact that those paints weren’t really all that great compared to what is available today. This is not to say that those paints were of inferior quality as the manufacturers generally used the best materials that were available with whatever the coatings technology of the period allowed. It is also important to consider that, as the decades progressed into the 1950’s & 1960’s, the time required to apply paint increasingly became a more critical factor in the assembly of a car and with the exception of some of the more expensive luxury cars, a few flaws such as runs, texture and overspray were considered to be acceptable and actually looked for by some show judging organizations today.

    In the early days of the automobile, master furniture and carriage craftsmen painstakingly applied primitive oil-based enamel or varnish primer and finish coatings by brush!  These finishes had somewhat poor opacity which required numerous coats for coverage and took weeks to dry. They used mainly ink pigments which all tended to be darker colors. These coatings did not withstand weather and sunlight very well and tended to become dry and brittle before long. Since those paint jobs didn't last all that long, in those days, it was common for an owner to get some paint at a hardware store or mail order catalog like Montgomery Ward along with a good horse hair or hog bristle brush and re-paint the car. With the idea of preserving the car, some folks even did it every year or so…by brush of course!

    A number of manufacturers including Ford in the Model T line, used a combination of brushing, dipping and even pouring to fully cover and protect the various parts of a car or truck. The 1920s saw the beginning of the introduction to spray equipment and nitrocellulose lacquers and primers which were developed together to speed application and dry time to a week or less which cut down dramatically the time required to paint a car although they still required labor intensive and time consuming hand rubbing to achieve a shine. This was not especially true in the production of early trucks however, most 1920s to 1960’s trucks were considered to be no-frills pieces of working equipment built to be used and abused, not to be fussed over and pampered. A great example of this is with 1930’s Model AA Ford trucks with that were built with dull, non-shiny, non-rubbed lacquer finishes. Rubbing-out was an extra-cost Ford AA truck option that according to a Ford service letter of 06-05-31; cost $15.00 extra for the cab, cowl and hood while a pickup bed cost $7.00.  In addition to reduced dry times, nitrocellulose lacquers were more durable and allowed the use of brighter colored although more expensive pigments. Interestingly, although with constant improvements, the organic-based nitrocellulose lacquer was used by some manufacturers well into the later 1950s when it was replaced with the much more durable acrylic lacquers and primers which were synthetics.

    Appearing shortly after nitrocellulose lacquers were enamels or more specifically, alkyd enamels and primers. These were generally a thicker material which required fewer coats than lacquers and usually were baked onto a partially assembled vehicle body by passing it through a large oven. This baking hardens the enamel and “flows” it out for a great shine and greater durability. Many more brilliant colors were available with the enamels which became possible due to the use of organic pigments which were widely popular with some of the more flamboyant and  attractive two and tri-toned 1950’s combinations. Eventually, the alkyd enamels too were replaced in the early 1960s by the new and superior acrylic enamels and primers favored by several manufacturers.

    Of course as we all know, any paint finish has a limited lifespan and with the harsh conditions it is exposed to, it is remarkable that it can last as long as it does given adequate care. With time and exposure, even the best lacquers will lose their luster, shrink and crack while enamels will fade out and become dull and chalky. These shortcomings and a move toward greater environmental friendliness led to the eventual changeover by most car and truck manufacturers to new base-clear, water-borne systems in the late 1970’s to early 1990s however this period was not without serious issues as many of us will recall the peeling clear coats of many vehicles from that era resulting in scores of cars and truck being repainted through factory warranty claims. Fortunately, the major paint manufactures quickly resolved those problems and the newer finishes are the most durable in history and require virtually no care to survive.

    What does this all mean to the owner of a vintage car or truck today who is planning for a paint job in the near future? To begin with, lacquer, while still available, is very difficult to buy today and is actually illegal for sale in certain areas of the country especially California. This is because of state and federally mandated VOC laws. VOC’s are Volatile Organic Compounds which are chemicals found in paints and solvents that are considered harmful to the environment and living creatures. In addition, with the limited life of a lacquer or enamel paint job and the clear superiority of some of the higher quality modern paints, unless you are striving for 100% authenticity on your restoration, it would probably be to your advantage to choose one of the modern alternatives to lacquer or enamel. With today’s modern paints, there are two major choices suitable for use on a vintage vehicle; Single Stage Urethanes also known as Single Stage Urethane Enamels and Two-Stage Urethanes. These urethanes are extremely durable, chip resistant, and chemical resistant and retain their gloss without dulling or fading. The single stage products are only similar to the old air dry lacquers and enamels in that they are one coating with the color, gloss and UV protection all in one material and do not require a clear topcoat. That is, the color is all the way through. They are all 2K formulations which means that an activator must be added per the manufacturer’s instructions which will chemically cure and harden the paint. They can be color sanded and rubbed out to provide that hard to describe yet pleasing, softer “polished bowling ball” look of a genuine lacquer paint job that looks so right on the rounded contours of a restored older car or truck. The two-stage products also known as “base-clear” are also 2K formulations requiring an activator but consist of a thin, no gloss color only film “base” which is sprayed on then top coated with multiple coats of urethane clear. The clear is then responsible for all the UV resistance, gloss and protection of the paint coating. While the two stage base clears do provide an attractive, deep, high gloss finish on more modern vehicles and the clear can also be color sanded and buffed to a glass-like surface, they often can be too glossy and look out of place on an older car.

    Another two-stage, base-clear system is the “water-based” coatings that are rapidly growing in popularity especially in today’s VOC sensitive world. It should be noted however that it is only the color base coat that is water based. At this time, there are no known, successful water-based clear coats. They are still solvent based formulations although the paint manufacturers are working hard to introduce successful, water based clear product.

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  • Gotta Love a 6 Pack in the Summer- Sandpaper ins and outs

    IF you’re just doing a small project, or you’ve run out of your full box or roll of sandpaper, or it’s just simply not in your budget to buy an entire sleeve or roll of sandpaper, these new 6 and 3 packs are the ticket!! You don’t have to buy the box of 100 and have it sit on the shelf until next season.  Click Here To Read Full Post...
  • 2014 Street Rodder Road Tour Impala Reassembly

    The body then went to primer and paint and was covered in a lovely shade of deep red. This thing is REALLY red, reminds me of the red found on a certain Italian super car manufacturer. With the body all painted and assembled the crew married the body and the roadster shop chassis together and continued reassembly. This is where the fun (and stressful!) part of the project begins. As each shiny part is bolted to the car the Impala takes shape and we can really see how great this thing is going to look rolling down the street.   Click Here To Read Full Post...
  • How to Paint Your Car- The Basic Steps and Methods Uncovered

    Painting a car is one of the most misunderstood parts of our hobby. It can be a daunting process to sand off the paint on your car, but it’s one of those jobs that things must get worse to get better.   Click Here To Read Full Post...
  • How to Choose a Paint Gun

    Time to buy a paint gun? Before parting with your hard earned money, read through this brief article to help in your decision process.

    With so many choices available, choosing a paint gun or paint guns to can be really confusing. With so many variables and individual needs, I can’t specifically tell you which gun to buy however I will attempt to filter through the many variables and provide a better understanding of what is available and why.

    For many years, paint guns were simple devices that used air flowing through small internal passages inside a metal paint gun body creating a vacuum to suck the paint through a tube, out of a canister attached to the bottom and when combined with a needle sliding through in and out through an orifice or nozzle, the paint mixed with air into small droplets becoming atomized then with air pressure, was forced out of the gun, through the atmosphere and landed on a surface, hopefully your car. A bit simplistic perhaps but basically how it was done. These were generally known as Siphon Guns and can be readily identified by the paint canister or cup, attached to the bottom of the gun body. Another similar version looking very much like a Siphon Gun, instead of vacuum, relied on supplied air to pressurize the canister, forcing the paint up through the needle and nozzle, becoming atomized then propelled through the atmosphere. These were known as Pressure Guns or “Pressure Pots” and most often used for production work or conditions where the gun will be inverted part of the time or on extreme angles. Although they were known for producing a beautiful finish in the hands of a knowledgeable painter, both designs required a fair amount of air pressure, usually 50 to 80 PSI to do their job and because they discharged a great amount of atomized paint into the air, were not very efficient, generating a lot of over spray. In some areas of the US, and Europe, these guns are actually not permitted for sale.  With some searching, they can still be found today, however they are considered to be old and inefficient technology.

    Another configuration of paint gun layout is the Gravity Feed. Gravity Feed guns are identified by the paint canister or “cup” being attached to the top of the gun body. The main advantage of this design is that the paint is fed to the nozzle of the gun with gravity and since no air pressure is needed to generate suction, it requires less pressure. Added benefits are a shorter path for the paint to travel and much easier cleaning. Also, most are newer designs which take advantage of the great advances in paint gun technology in the past 10 years.

    Note: It is a common misconception that if it is a gravity feed gun, it must be an HVLP. Not necessarily. Some of the really inexpensive guns may be made to look like an HVLP but are in fact based on old high-pressure technology. The best advice here is to look very carefully at the gun, the box, any included literature containing specifications and don’t hesitate to ask questions of the seller before forking over hard earned money.

    This leads us into the subject of HVLP guns which is an acronym for High Volume Low Pressure. These are by far the most commonly available units today. Ok, you may be wondering what this High Volume Low Pressure actually means. The “Low Pressure” refers to the air pressure required to operate the gun properly. The majority of HVLP guns today require from 15 to 30 PSI (Pounds per Square Inch) which is the force of the air needed to function adequately. The individual gun will state this in the included specifications. The “High Volume” is the CFM (Cubic Feet per Minute) which is the amount of air needed to get the job done. Some guns require as little as 3 or 4 CFM while others will need 10 to 15 CFM. At this point it is VERY important to point out that the PSI and CFM requirements are specified AT THE GUN INLET (I will touch on this in greater detail a little further on in this article). In addition to your main regulator at the air compressor, you need to always have a true gun regulator attached right at the gun inlet to properly measure inlet pressure, they also serve to prevent sudden pressure spikes when opening and closing the trigger.

    Another term you may occasionally encounter is LVLP which obviously describes a Low Volume Low Pressure gun. Although virtually identical to an HVLP, the combination of both a lower PSI and CFM requirement will earn a gun this designation. They are generally among the most efficient guns out there and waste little paint however most of them are at the high end of the price scale.

    The guns described above are available in full-size as well as smaller versions that you would use for laying a single-stage color or base-clear in a tighter area or over small parts. Named “Mini Guns” by most manufacturers; their usefulness in shooting door jambs or covering small repaired areas is why they are frequently called “Jamb Guns” or “Spot Guns”.

    All paint guns share the same basic internal component design that is; internal passages designed for optimal flow, a trigger controlled, sliding “needle” which is a metal rod with a sharp point that extends into and out of the “nozzle” which has a corresponding size to match the needle (they are paired in sets and always used that way) and the “air cap” which surrounds the nozzle and injects air into the paint stream and shapes the spray pattern or “fan”. In addition, they also have assorted springs, ferrules, bushings and seals. The aforementioned “needle” and “nozzles” are sized by the hole in the nozzle where the paint is discharged through. They are measured in millimeters and can be from 1.0 to 2.0 mm with most in the 1.2 mm to 1.8 range. Again, no direct rules apply here as different manufacturer’s nozzle/needle sizes will work better with some materials than others, some basics are; 1.2 mm/1.3 mm for base colors, 1.3/1.4mm for clears and single stage urethanes and 1.5 to 1.8 for heavier-bodied primers and sealers. 1.0mm is what is most often found in a mini-gun.

    Earlier in this article I mentioned “air requirements at the gun inlet”. This is a critical point in that all compressors have a CFM rating which will appear as this example; 16 CFM@90 PSI. I stress this as being very important since this rating is at the OUTPUT of the compressor tank, when the compressor is new, with ideal atmospheric conditions, moon in the right phase…you get the picture. Add in ½ dozen air fittings, tank regulator & filter, 50 feet of air hose a few more fittings and if you are lucky, you have 10 or 12 CFM at the gun and if your gun requires more CFM, the paint job will suffer and the gun looks like the bad guy. Note: horsepower is not a good rating of a compressor, always refer to the CFM rating. If you suspect that your compressor may not be up to the task, there are things you can do to help. 1st, use as short of a hose as possible and go with as large of a diameter as you can. A ½” I.D. hose is much better than a 3/8” hose. Try to eliminate fittings if you can, elbows especially. Go with the largest tank Filter/Regulator unit that you can afford. If you need help, there are several excellent online sites that help you calculate air pressure and CFM loss through pipe and fittings. Another important point is that moisture and oil are responsible for ruining probably 70% of paint jobs. You MUST have clean dry air to the gun. Be sure your compressor tank is drained of water, use a good quality moisture and oil trap (in-line desiccant systems work well too). Buy a new air hose and keep it dedicated just for painting to minimize the chance of intruding oil or contaminants to you paint gun.

    The controls on most paint guns are quite similar with the air-flow, paint-flow and fan knobs. The fan knob regulates the width of the “fan” or spray pattern which is normally a vertical elliptical shape however this is determined by the horizontal or vertical orientation of the Air Cap. This is determined by the user. Since all guns are different in their base settings, consult the instructions supplied with the gun as a starting point. Each gun design has an individual “feel”. Get familiar with it, waste some paint and practice, practice, practice before tackling that paint job on you old car or truck

    There is one other type of painting system that certainly bears mention here and that is the Turbine systems. These are great for those without a compressor or requiring portability. Basically, if you can imagine using the outlet hose of a powerful vacuum cleaner on a specially designed paint gun and heat that air, you have the idea of a turbine paint system. Of course they are a bit more complex and specific than that and cost can vary widely. They provide a huge amount of CFM, the intake air is filtered and the output is heated to provide a dry air supply. I have tested several of them and the better quality units do work quite well. The only caution is that many (but not all) are designed for painting backyard storage sheds and garage doors but not cars & trucks so choose carefully and take note of the included needle/nozzle set size. Some are supplied with 2.0 mm and larger needle/nozzle sets however the higher quality machines offer optional automotive painting sizes.

    One final word on cleaning. Failure to take the time and effort to properly clean them has killed more innocent paint guns than any other cause. The cheap, clean-up grade of lacquer thinner or acetone available by the gallon from one of the large discount stores works well. Another alternative is one of the aerosol gun cleaning agents available from many paint and supply houses. To avoid damage, begin cleaning as soon as you are finished painting and minimize the exposure time to the solvent. NEVER leave a paint gun to soak in solvent as it will ruin any plastic internal parts and rubber seals. Drain unused paint from the cup, wipe out as much as you can. Pour a few ounces of the solvent into the cup and spray it out into a rag or wad of paper towels (be careful not to have it spray back at your face and I trust you would still be wearing protective gear at this time). Wipe of any remaining paint form the exterior then remove the air cap and nozzle, put several more ounces into the cup then with the air disconnected, squeeze the trigger and allow the solvent to stream out until it is clear. Put the air cap and nozzle back on Hook the air back up then once more, spray the remaining solvent into the rag.

    In summary, shop carefully and hopefully use the information I have provided. You must make the determination on how often you will use the gun, whether to but just one and acquire the additional needle/nozzle sets or buy two or even three separate guns. Many painters have a dedicated color gun, a clear gun and a primer gun. Generally, with the more expensive guns, a great deal of engineering and development goes into optimizing internal flow and atomization characteristics also, they tend to be much longer lasting, these are usually bought by the everyday painter. For the dedicated hobbyist, there are quite a few decent guns and sets available for $200/$300 or so. 

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