ASE REFINISHING PRACTICE

A paint surface has tiny blisters. Painter A says that the blistering may be caused by grease contamination of the surface. Painter B says that water contamination of the surface may be the cause. Who is right?

Both painters are correct. Blistering can be caused by contamination, such as oil, water, grease, sanding deposite, or tree sap, on the surface under the paint. Using the incorrect hardeners or reducers can also cause blistering.

Painter A says that overloaded exhaust filters change the cabin pressure in the booth. Painter B says that overloaded spray booth filters do not pass enough air. Who is right?

Both painters are correct. If the exhaust filters are overloaded, they are getting plunged with paint overspray. This will prevent sufficient airflow through the filters and increase the cabin pressure in the spray booth.

A paint surface has runs in it. Painter A says that improper paint mixing may be the cause. Painter B says that improper spray technique may be the cause. Who is right?

Both painters are correct. If the paint is mixed to thin, it will run very easily. If the painter does not move fast enough, the gun is too close to the surface, or the reducer is too slow for the shop temperature, runs can result.

A vehicle has peeling paint. Painter A says that peeling is caused by a loss of adhesion between the paint and the undercoat. Painter B says that to correct peeling, all peeling paint must be removed. Who is right?

Both painters are correct. If the paint on the vehicle is peeling, it is caused by improper surface prep, which causes a loss of adhesion. If this problem exists, all the peeling paint must be removed, the surface sanded, and then refinish.

Painter A says that to determine if a nonwhite paint surface has clearcoat, the surface should be sanded to see if it sands white. Painter B says the sanding test will not work if the vehicle is white. Who is right?

Both painters are correct. Sanding on a non-white color will determine clearcoat. Sanding white paint cannot be used to determine clearcoat.

Painter A says the dull dry look of weathered paint is called oxidation. Painter B says the dull dry look of

Both painters are correct. When the paint weathers and starts to break down it is called oxidation. Often with this oxidation the paint looks white and chalky. This is called chalking. Oxidation and chalking are both part of the oxidation process.

Two painters are discussing the removal of body trim. Painter A states that he would use a heat gun to remove body trim. Painter B states that he would use an eraser wheel to remove the residual attachment tape left behind after removing the body trim. Who is right?

Both painters are right. A heat gun can be used to heat a trim molding to release the adhesive and remove the molding. Many guns have heat controls, or you can use air without the heat. The eraser wheel removes the adhesive without damaging the painted surface.

A 100 percent reduction is also

A 100 percent reduction is one part paint to one part reducer. One part paint to two parts reducer would be 200 percent reduction. Two parts paint to one part reducer would be 50 percent reduction. One part pain to one-half parts of reducer would be 50 percent reduction.

What is the easiest type of blend to make?

A basecoat/clearcoat panel is the easiest blend to make. You can blend the color and clear the whole panel. A basecoat/clearcoat spot would be blending the clear also. This is not as easy and not recommended by some vehicle makers. A tri-coat or single stage spot is not as easy because, again, you have to blend the clearcoat.

A spray panel used to check for color match on a tri-coat finish is called a

A let-down panel is designed to check how many coats of pearl are required to match an existing finish. Each coat of pearl typically makes the color darker. If you get too many or too few coats of pearl on the panel it will not match.

What can be used in bare metal

A self-etching primer is designed to go directly over bare metal. It is the preferred method in many shops today. Another quality method to prevent corrosion is an etching acid on the bare metal to clean it, followed by a conversion coating, and then a two component primer. A epoxy primer can be sprayed over bare metal also. It is usually recommended to do this in smaller areas only. A topcoat does not adhere to bare metal. It requires some type of a primer underneath it.

What are vehicle substrates

A substrate is a surface that is going to be painted. Steel is the most common substrate on a vehicle today. Both rigid and flexible plastic are becoming more popular. Tempered glass is not considered a substrate because it is not a painted surface.

What is least likely to be picked up by a tack rag

A tack rag will pick up loose particles on the surface to be painted. It will pick up hair, dirt, fuzz, lint, and so on. A tack rag is not absorbent so it will not pick up water from the surface.

Two-part putty consists of

A two-part putty consists of putty and a hardener. There are one-part putties. A two-part putty will be a stronger material so it is more commonly used today. Single-part putty creates a weak link in the repair.

Tape tracking is corrected by

Applying tape to a paint surface that is too fresh causes tape tacking. When you lift the tape, it leaves tracks in the finish. To correct the problem, sand the tracking out and apply paint over the area. Buffing by itself usually will not take out the tracks. Hand glazing will not remove the tape tracks; it is not aggressive enough. However, grinding is too aggressive for this type of a repair.

Bleed-through causes

Bleed-through causes discoloration on the undercoats and the topcoats. Bleed-through does not cause pinholes. Molting is a spray technique problem. Bleed-through cannot cause rust. It is caused by bare metal, moisture, and oxygen.

A hazy, milky, paint surface is also known as

Blushing is when the paint gets milky look to it from humidity trapped in the paint film.

Painter A says that chip-resistant coating is usually applied before paint. Painter B says that chip-resistant coating prevents stone chips. Who is right?

Both painters are right. Chip resistant coatings are normally applied under the paint. A few of them are clear so they can be applied over the paint, but most technicians apply them under the paint anyway because there is less chance of changing the color and making the coating more noticeable. Chip resistant coatings are applied to help prevent rock chips as they provide some cushion for the paint film when a rock strikes it.

A paint surface has contamination. Painter A says that a dirty spray booth could be the cause. Painter B says that a dirty vehicle could be the cause. Who is right?

Both painters are right. Contamination in a paint job can come from various places. If the vehicle or the booths is not clean, you can get contamination in the paint. These are the most common areas. Contamination can also come from the painter or the air lines.

Painter A says that dirt may be removed from sealer with a tack rag. Painter B says that dirt may be removed from the sealer with nib sanding. Who is right?

Both painters are right. If the dirt is not embedded into the sealer, it can be removed with a tack rag. If the dirt is embedded into the sealer, then nib sanding will remove it. Which method works best depends on the shape of the particle and where in the sealer surface it is sitting.

Painter A says that the initial blowing off a vehicle with compressed air should take place outside of the spray booth. Painter B says that the vehicle should be blown off with compressed air inside of the spray booth. Who is right?

Both painters are right. Initial blowing off of the vehicle should take place outside the booth, but it should be done once the vehicle is in the booth also. Many painters blow the vehicle off in the booth following the air blower with a tack rag. The surface is tacked again before painting. If the vehicle is not blown off in the booth, there may be dust from the shop on the vehicle that will contaminate the paint.

Painter A says that a sealer may be water based. Painter B says that a sealer may be solvent based. Who is right?

Both painters are right. Sealers can be either solvent-based or water-based. Solvent-based sealer's are more common. Water-based sealers are used more commonly and VOC-regulated areas or if the surface is solvent sensitive. Water-based sealers will help prevent lifting when painting. Water-based sealers also have some solvents in them.

A paint needs to be mixed. Painter A says you should read the paint formula for the amount of each tint required. Painter B says that you should use a digital scale to weigh the amounts of tints. Who is right?

Both painters are right. To properly mix a paint color, you need a formula to determine how much of each tint to add. A digital scale is used to measure these amounts. These scales may measure in grams or parts. Some scales measure both ways. Make sure you use the range from which the paint company built the formula, otherwise the paint may not fit in the can in which you are mixing.

A vehicle needs to be masked. Painter A recommends using liquid mask. Painter B recommends using plastic film. Who is right?

Both painters are right. When masking a vehicle there are a number of options. You can cover the vehicle with liquid masks, plastic sheeting, or masking paper. In the area adjacent to where you are painting, you should use masking paper for about 18 inches around the paint area.

At what time during the repair process should dirt and road be removed from the area of repair?

Contaminants on the surface should be removed after removing any trim so you can get under the trim also. The surface should be clean before any of the repair operations. If the surface is not clean first, contaminants can be forced down into the pain and cause problems during the repair.

What paint problems is caused by static electricity

Dust contamination is caused by static electricity. Static electricity building up in body panels will attract small airborne particles of dust, causing contamination of freshly painted surfaces.

A painted surface has small craters caused by silicone containment. These are also called

Fish-eyes are caused by silicone containment on the surface.

The simplest way to remove swirl marks is by

Glazing is a procedure used to remove swirl marks. Some glazing products use a filler to fill the swirl marks; some products remove the swirl marks with a very fine abrasive. If the swirl marks are severe, they may require buffing, followed by a glaze. Buffing creates more swirl marks. Sanding may be necessary if the swirl marks are extreme, followed by buffing and glazing. Grinding will require priming and refinishing.

What is arcing problem?

Heeling is when the bottom of a spray pattern is closer to the surface than the top of the spray pattern. Blending is stepping out one color over another so the difference is harder to see. Banding is painting the edges of a panel before painting the flatter surfaces.

What is used to describe hue

Hue is the tint of a color. Is it red, blue, or green? The four primary colors on a typical color wheel are red, green, yellow and blue. Hue is described in relation to one of these colors. A color can be redder or yellower. It is not described as oranger.

What may cause dry spray

If the air pressure is too high, it can cause a dry spray. If you move too fast, you will get a dry spray. If you move too slowly, you may get runs and sags. If you are too far away from the surface, you will get a dry spray. If you are too close to the surface, you may get runs and sags. If you have insufficient material you can get a dry spray.

The front door on a vehicle has been painted. There is a slight mismatch. What should the painter do?

If there is a slight mismatch, you should blend into the adjacent panels. If the front door was painted, blend into the fender and the rear door. With a slight mismatch there should be no reason to go into the quarter panel.

What may cause runs?

If you are moving too slow while painting, it can cause runs in the paint. If you overreduce the paint, it will run easier because it is thinner bodied and does not hold onto the surface as well. If you do not allow sufficient flash time, the extra buildup of wet paint can cause runs. The only instance that will not cause runs is having the gun too far away from the surface. If the gun is too close runs could occur.

What problems can be caused by buffing?

If you both too much on a paint surface, you can rub right through the pain or clear. If the surface gets too hot or you run out of compound word booking, it will bring the paint. If you both on a surface before has a chance to cure or let the solvents evaporate out, the paint will become door because you are actually working the rubbing compound into the paint. Solvent popping is a paint application problem; buffing does not cause it.

What does the digital mil thickness gauge show?

It measures the thickness of a paint film.

A reaction of the paint surface that looks like the paint is wrinkling up is called

Lifting is when the top coats are reacting with the undercoats or previous finish. It looks like the paint is wrinkling up. Wrinkling can also be caused by the paint film being too thick and not drying properly. This is more common on some older finishes. Blistering looks like small bumps on the surface not a wrinkling effect. Blushing is when the paint gets a milky appearance caused by humidity. Mottling is when the metallic does not lay evenly and the paint looks streaked or spotted.

What is the name for paint cracking

Micro-checking, crows feet, and line checking are all examples of paint that is cracked. Chalkin is when a paint surface turns white as it gets older.

A streaking of a metallic paint surface is called

Mottling is when the metallic does not lay evenly and has streaks of lighter and darker color. Sometimes it is called tiger or zebra striping. Blushing is when the paint looks milky; this is caused by humidity problems. Lifting is a reaction between the topcoat and the underlying finish. Blistering looks like small bumps in the paint surface.

OSHA stands for

Occupational Safety and Health Administration. This organization makes sure we have a safe work environment.

Painter A says infrared drying is usually slower than heated air drying. Painter B says that an infrared lamp dries paint from the bottom up is better than infrared lamp that dries paint form the top down. Who is right?

One of the advantages of using infrared for curing is that it dries from the bottom up. This helps prevent trapping solvents under the surface of the paint and causing loss of loss of gloss problems. Since it is not trapping solvents, the drying process faster.

Catalyze paint is to be sprayed. Painter A says that a supplied air respirator should be worn. Painter B says a cartridge respirator should be worn. Who is right?

Painter A is correct. All paint manufacturers recommend using a supplied air respirator when spraying catalyzed paint. A cartridge respirator is not enough protection.

A clear coat has minor discoloration from tree sap. Painter A says that you should sand and buff. Painter B says you should sand and repaint. Who is right?

Painter A is correct. When repairing surface defects in a paint surface, you should always try the least aggressive method first. In this case, sanding and buffing is less aggressive than painting.

Painter A says that a mild wax and grease remover does not penetrate into the primer-surfacer and cause a sandscratch swelling problem. Painter B says that a mild wax and grease remover is used to clean after painting. Who is right?

Painter A is right. A mild wax and grease remover is designed to clean the surface before painting. It will not penetrate into the primer-surfacer and cause sandscratch swelling problems. If you use a stronger wax and grease remover, this is a possibility. A stronger wax and grease remover should not be used before painting, only before starting the repair process to remove heavy road tar and wax.

Painter A says that the spray gun should be cleaner after each use. Painter B says that the spray gun should be inspected before each use. Who is right?

Painter A is right. A paint gun must be cleaned immediately after each use as many products sprayed today are catalyzed. That means they have a pot life and will get hard after a certain amount of time. If the pain gets hard in the gun, it may ruin the gun. You may not be able to get the paint out of the gun. Even if the pain is not catalyzed, it is a lot faster to clean the gun while the pain is still soft. Once it gets hard, it takes a lot longer to clean.

Painter A says block sanding is done to level the surface of the panel. Painter B says when block sanding, a finer grit will cut straighter. Who is right?

Painter A is right. Blocking is done to level the panel surface before painting. To get the panel straighter, use a coarser grit. A coarser grit will cut straighter. However, do not use a grit that needs to be primed and blocked again. Some technicians start with 220- 320 grit to get the surface straight and then move to a finer grit. Many technicians finish blocking with 400-600 grit and find that they do not need more primer to cover larger sandscratches. Which grit to use depends on the process applied in the shop, which products are used, and personal preference.

A paint surface has excessive orange peel painter A says that it was caused by an improperly adjusted spray gun. Painter B says that it was caused by too little flash time between coats. Who is right?

Painter A is right. Orange peel can be caused by not having the spray gun adjusted properly. It cannot be caused by too short of a flash time. If the flash time is too short, the paint coats will flow together more, creating less orange peel.

Painter A says featheredge splitting can be caused by spraying paint too dry. Painter B says featheredge splitting may be prevented by using a sealer. Who is right?

Painter B is correct. Featheredge splitting can be caused by spraying the paint too wet over a sensitive substrate. To prevent featheredge splitting, apply a water-based primer or a sealer, or spray dry coats of paint. If the problem is severe, it may be necessary to remove the sensitive undercoat.

Painter A says that graphics decals must be applied to bare metal. Painter B says that a graphics decal is applied only after all painting operations are completed. Who is right?

Painter B is correct. Graphics decals must always be applied to a painted surface. Graphics decals do not adhere very well to bare metal, and you will sacrifice corrosion protection by putting them over bare metal.

A painted surface has light overspray. Painter A says that you should remove it with lacquer thinner. Painter B says that you should remove it by buffing. Who is right?

Painter B is correct. Light overspray can usually be removed by buffing. Do not use lacquer thinner because it may damage the paint surface or other surfaces. If the overspray is bad, it may require sanding and buffing.

Painter A says that seam sealer must always be primed before painting. Painter B says that bare metal should be primed before splaying seam sealer. Who is right?

Painter B is correct. Seam sealers are not designed to go directly over bare metal. A two-component primer should be applied first, then the seam sealer. Many seam sealers require priming before painting, but there are some you can paint directly over.

A paint user face has several circular, white outlines visible in the paint. Painter A says that these are rust spots. Painter B says that these are water spots. Who is right?

Painter B is correct. Water spots will look like white circular outlines on the surface. When rust starts to show up in a paint surface, there will be bubbles in the paint.

A decal needs to be removed with minimal damage to the underlying paint. Painter A says to grind it off. Painter B says to use a rubber stripping wheel. Who is right?

Painter B is right. A few methods can be used to remove a decal without damaging the paint underneath. Rubber striping wheels are designed for this purpose and work well. You can also use a heat gun and razor blade, but you must be very careful with the razor blade. The method you choose depends on the size and condition of the decal. Grinding will destroy the paint surface.

Painter A says that dry sanding keeps the surface cleaner. Painter B says that wet sanding cuts faster than dry sanding. Who is right?

Painter B is right. Wet sanding cuts faster than dry sanding because of the lubricating action of the water. Wet sanding also keeps the surface cleaner as it washes away the sanding dust while you are sanding. Additionally, it keeps the sanding dust from floating in the air so you do not breathe it while you sand.

A flexible plastic part is to be refinished with base coat/clearcoat paint. Painter A says that you should add flex agent to the base coat. Painter B says that you should add flex agent to the clearcoat. Who is right?

Painter B is right. When painting flexible plastic parts with basecoat/clearcoat finishes, flexible additive should be added to the clearcoat. There is no need to have a flex agent in the basecoat because it is so thin that it will flex without it. Clearcoat has a greater mil thickness, so it requires flex agent.

A surface has hand scratch swelling. Painter A says that the surfaces may not have been properly sanded before painting. Painter B says that the paint was sprayed on too dry. Who is right?

Painter is correct. Improper sanding of a surface can cause sandscratch swelling. If you use too coarse a grit, this can happen. Spraying the paint too wet will cause the solvent to soak into the undercoat and swell the sandscratches.

Etching prime is used to

Primer providers adhesion and corrosion resistance. Two-component primer provides the best corrosion protection and adhesion for other undercoats and topcoat. Primer-surfaces provide filling qualities. Sealers help seal the undercoats from the topcoat, and some sealers are designed to prevent bleeding of colors from previous paint jobs. Bleeder sellers are not used much today because the pigments in the new finishes are stronger and more resistant to the bleeding.

What is an example of airborne industrial contamination

Rail dust, acid rain, and soot are all examples of industrial contamination. They are all byproducts of industry. Tree sap is considered organic contamination.

A surface to be refinished is determined to have an existing film thickness of 12 miles, and is undamaged. What procedure should be done prior to refinishing.

Reduce existing paint thickness to 6 mils or less to prevent excessive film build after the new finish is applied.

Exterior moldings are attached using

Silicone adhesive is not used to attach exterior moldings. Silicone-based adhesives are not compatible with painted surfaces.

What can cause the loss of gloss?

Silicone contamination causes fish eyes. It cannot cause a loss of gloss. If you have the spray gun adjusted improperly, such as having the fan pattern too large, it can cause a loss of gloss. If you use too fast of a reducer, it can cause a loss of gloss. If you apply wet coats of paint over undercoats that are not properly cured, the reducers can soak into the undercoat and then start working their way back out, causing a loss of gloss.

What type of paint is the easiest to match

Single-stage paint can be solid or metallic. It can be various types of paints such as lacquer, enamels, and urethane. A base coat needs to be clear coated so it is not single stage paint.

Solvent pop may look like

Solvent popping may look like pinholes because as the solvent works its way to the surface, it can pop and leave holes in the paint surface.

The letters TPO are on a plastic part. The letters stand for

TPO stands for thermoplastic olefin.

What is a hazardous waste

The cleaning process removes dirt, oil, road tar, grease, and other oil and water-based contaminants. It does not remove paint from the surface.

Pattern control knob

The fluid knob is located below the pattern control knob.

The gradual change in height from bare metal to topcoat is called

The gradual change in height from metal to topcoat is called a featheredge.

In a multi-stage paint, the intermediate layer is the

The intermediate coat is typically a pearl coat. Some multi-stage finishes have a tinted clear as the intermediate coat, but peal is more common.

What factor determines what size of the fluid tip orifice to use?

The size of the fluid tip to use is determined by what you are spraying, and its viscosity. If you do not have enough air volume, the gun will not spray properly with any size tip. Air and paint pressure are adjusted after the tip size is chosen for the product you are spraying.

What are the ways to prep for a blend?

To prep a blend area for refinishing you must use a fine sanding grit. A grit of 320 is too course. Sanding grits of 801 and 1,000 and a light scuff pad are all recommended from different paint manufacturers. If the sandscratch is too coarse, the blended paint will not be able to cover the scratch and it will show in the final product.

Which of the following is a problem associated with clearcoat application?

When spraying clear you can cause sags, runs, or orange peel. When spraying metallic colors, for example, the color may change depending on the spray technique. A mismatch can come from excess thickness of a clearcoat on light colors such as white, but that is not a problem with the application process.

A slow-drying solvent is used during cool conditions, about 60F. What could result from this

When spraying paint during cool conditions, a fast reducer should be used to decrease drying times. If a slow drying reducer is used, the paint will stay wet too long and sags will develop.

Painter A says that the air pressure of an HVLP gun is determined at the air cap. Painter B says that the HVLP spray gun's manufacturer will recommend proper air pressure. Who is right?

Both painters are right. Air pressure is measured at the air cap on HVLP paint gun. Some paint gun manufacturers have special air caps with gauges to attach the gun while setting the air pressure. They are not meant to be left on the gun while spraying. Paint gun manufacturers provide suggested pressures for different types of paints. Paint manufacturers also provide suggested pressures for their products when used in different types of spray guns. These suggested pressures may be different for different painters due to individual techniques.