Daily Archives: January 24, 2012
The first photo shows me spraying the color layer on the car. The color layer, in this case white, is what give the car its color. This car had two small dents, one on each side of the roof, so I shot those areas then blended across the roof.
Blending is the technique to hide minute color changes. The human eye is simply amazing in its ability to distinguish subtle shades in color. The number of colors that the average person can see is somewhere in the millions. With that kind of resolution, it is obvious that if the color of the new paint isn’t dead on the money, the human eye can tell the difference … especially if they are directly adjacent to one another. Blending disguises the difference in color, if there is any, by blending the two colors so the eye cannot perceive the difference. It is an old technique, but sometimes you can’t improve on the tried and true.
Photographs two and three show the roof after the application of the color layer. Looks pretty good, if a little flat. The reason the color looks so dull and lifeless is because it is. A two-stage paint process, the process we use at JMC AutoworX, the base coat, what I call the color layer, dries to a nearly flat finish. It is the clear coat that provides the gloss, and protection, to the finish.
The last two photos show the same roof after the application of the clear coat. The clear make a big difference doesn’t it? It is the clear that give the paint its depth and luster, in addition to providing protection to the color layer underneath.
After the clear coat dries, we will strip the masking off, snap the roof rails back on, surprisingly undamaged by the door falling on them, and get the car cleaned up and ready to return to the owner.
And those nasty dents? All I can say is, “What dents?”
I throw a lot of terms around on this site. Primer, sealer, blocking … it can all be very confusing. To help those who don’t do this every day, I am providing a handy definition guide to help everyone understand the terminology. I will also post these in the FAQ (Frequently Asked Questions) section for future reference.
Acrylic (Enamel) (Paint): A common type of paint used for automotive finishes. Not as durable as a urethane enamel, acrylic enamels can be polished to a high gloss finish like a lacquer paint.
Base Coat: This is the actual pigmented color that covers your car. I frequently refer to this as the color layer in this blog for clarity.
Blend(ing): A technique for matching old paint to new. Blending feathers the newly applied paint into the existing paint so the eye cannot detect a change in color if one exists.
Block: A flexible object around which sandpaper is wrapped. The block prevents the introduction of imperfections into the surface caused by hand sanding and allows the sandpaper to remove more material from high spots while skimming over low spots, producing a smooth and even surface.
Blocking: The process of using a block while sanding.
Body Filler: A product that dries to a hard surface suitable for sanding and shaping. Body filler is designed for smoothing and filling of shallow dents, not for major repairs.
Booth: See Paint Booth.
Buffer: A high-speed tool used to apply and remove polishing compound. See Polishing.
Candy: A thinned base coat applied over the regular base coat to produce a deeper, richer color.
Catalyst: An ingredient that causes a chemical reaction by interacting with the resins of the paint allowing it to cure .
Clear Coat: The final coating applied over the base coat to protect the finish and provide the gloss.
Enamel (Paint): A general term for paints that dry to a hard, durable finish. Acrylic enamels and urethane enamels, along with hardware store type spray paints are all enamel paint.
Epoxy Primer: An undercoat that can be applied over etching primer or bare metal to seal the body from moisture and provide a barrier to damage, such as rock chips and scratches.
Etching Primer: An undercoat that is applied directly to bare metal. The etching primer bonds directly to the metal surface to provide rust protection and adhesion to the following layers. The etching primer and epoxy primer work well together as a single unit.
Filler: See Body Filler.
Flake: See Metal Flake.
Gloss: The luster or shininess of paints and coatings are generally classified as the gloss. Common definitions are flat, semi-gloss, or gloss; the latter having the highest reflecting ability.
High Solids Primer: A product used to remove the tiny imperfections from cars. Typically used under the most demanding finish, such as our High Performance Finish, a high solids primer provides the smoothest base possible for the base coat and clear coat. It functions in the same capacity as body filler, but is used over the entire car and is applied as a spray.
Lacquer (Paint): A type of paint characterized by fast drying times and the ability to be polished to a rich and beautiful gloss. Poor durability and chemical resistance has led to their replacement by enamel paint.
Long Blocking: See Blocking.
Metal Flake: Tiny bits of various colored flakes that can be added to the base coat to give extra sparkle to the paint. Metallic paints get their name from the inclusion of metal flakes.
Metal Work: A general terms for heavy metal repairs, such as cutting out rusty areas and replacing them with new sheet metal.
Paint: A general term for the various undercoats, base coats and clears that taken together forms the finish on your car.
Paint Booth: An environmental control chamber for the application of various sprayed substances that make up the paint on your car.
Paint Gun: A tool used by painters to apply sprayable substances to a vehicle. A paint gun is typically powered by cleaned and dried compressed air.
Pigment(s): The substances that are mixed into the base coat to give it its color.
Polish: The act of using a high speed buffer along with various polishing compounds to increase the luster of a paint finish. This is typically the final step of painting a car.
Polishing Compound(s): Substances that contain ultra-fine abrasives used to restore or increase the luster of a paint finish. Polishing compounds are available in various coarseness’s depending on the amount of abrasion needed.
Primer: A general term for an undercoat that is applied to seal and protect the metal or plastic before the application of the sealer and paint.
Sanding: A general term for the use of sandpaper for smoothing, cleaning and the removal of imperfections. See Blocking.
Sealer: An undercoat that is applied over all previous layers before the base coat is applied. The sealer fills any tiny sanding scratches and provides a consistent color base in one of seven shades of gray. The sealer and base coat work together as a unit to provide the color for your car paint.
Slick Sand: See High Solids Primer.
Shoot: A slang term for using a air powered paint gun to apply the various undercoats, base coats and clears. Typically would be used as in, “I have to go shoot this car.”
Tack: To remove any residual dust with a tack cloth.
Tack Cloth: A lint free cloth impregnated with a chemical that leaves the cloths slightly tacky. A tack cloth wiped over a surface will cause any dust or loose particles to adhere to the cloth so it is removed from the surface.
Trim Out: The act of applying an primers, sealer and paint to the part or parts of a body panel that cannot be reached after assembly.
Two Stage (Paint): A paint system in which the color is applied as a base coat followed by a clear coat to provide gloss and protection.
Undercoat: Any of the primers and sealers that are applied before the base coat.
Urethane (Enamel) (Paint): A type of paint used in most automotive finishes. Urethane paints are very durable and require the use of a catalyst.
Wet Sand(ing): Sanding of a surface while the surface is wet. The water provides lubricating properties to prevent the removal of too much material and washes away sanding dust so that the effects of the sanding process can be seen.
The replacement parts for the Versa arrived at the shop today. You may recall that last week two cars with smashed door arrived at the shop at the same time, both a victim of being backed into in a parking lot. This Versa was one of those two cars.
We didn’t have time to paint the car today, but we did get the parts trimmed out.
When new factory parts arrive they are already coated with a bare metal primer. This primer could be scuffed or damaged in shipping, so in order to give my customers the best possible paint job, I always sand and seal the parts, just in case.
The sealer seals all the layers below it and provides a color base for the paint. The sealer comes in seven shades of gray, from white, to almost black. Each paint color specifies one of these seven shades to ensure a accurate color match.
Trimming out a car is applying primers, sealers and paint to areas of a body panel that are difficult or impossible to reach after assembly. It is just another way to ensure that rust can’t get a finger-hold anywhere on the car, and that the finish looks its absolute best.
Doing the best job we can on every job we do is how we roll here at JMC AutoworX.
This Nissan is in the shop to have a couple of dents repaired, dents caused by a garage door falling on the car. What is surprising about the damage is that it only happened on the edges, not all the way across. I don’t even pretend to understand how that could happen. It doesn’t really matter I guess, I don’t have to understand how it got bent, only how to repair it.
Because the car is white the dents didn’t show up on the camera, so the first picture shows the two areas sanded and covered with a layer of body filler. Body filler has received a lot of negative attention in the past. This is generally because of improper use, trying to use it for purposes for which it was never intended. But in this case, it is the perfect tool for the job. To try to pull these slight dents out would be prohibitively expensive, but a thin skim of body filler will fix the problem with minimal cost.
Body filler is designed to work as a thin layer to even shallow dents and dings, like these. The filler is smeared over the dent in thin layers until the filler is built up beyond the height of the surrounding metal. After it has dried, the filler is then blocked to remove most of the material, smoothing and shaping the filler to match the lines of the car.
You will notice in the second photo how rough and ugly the raw filler is. This is the way the filler looks before any blocking takes place. The next two photos, numbers three and four, I am actually blocking the car. Blocking is nothing more than wrapping sandpaper around long flexible blocks which are used for sanding. You can see the sanding block in my hand in these pictures.
The block evens and smooths the surface of the filler because the extra length of the block causes the high places to be removed faster by allowing the block to really dig in, removing more material. At the same time, the length allows the sand paper to float lightly over the low places removing less material. The sanding process continues until the filler is perfectly smooth and even with the lines of the car.
The fifth picture shows the car all taped off, ready for primer, and the top being cleaned of any wax, dust and oils. That little blob of greenish-gray is all that is left of the filler after blocking. Now only factions of an inch thick, smoothed and shaped to match the rest of the roof, it is ready to be primed and painted. The roof color looks flat in the rest of these photos because the clear coat has been lightly sanded to rough up the surface for better adherence.
The last three photos show the two areas that were repaired sprayed with a primer. The primer seals the layers below and provides a coating so the color and clear layers have something to bite into. Pictures six and seven show the primer still wet and slightly glossy, but it dries to a nearly flat gray, as you can see in the last photo.
The car was blocked and primed yesterday. Today we will get the repaired area painted and cleared. After the paint is good and dry we will snap the roof rails back on, get it cleaned up, and this car will be ready to go back to its owner sometime on Wednesday.