[7TRoadster]

Spray Body Jams and Recesses

Read and follow the label on the can for best spraying conditions, temperature, humidity, mix ratios, etc. Match those conditions as closely as possible. Use the correct temperature reducer, there are three; fast, mid-temp and slow. Fast is used in the cooler temperature ranges as the solvent evaporates quicker reducing the time when paint sits on the car wet. This reduces tendencies for runs and sags. Mid-temp is about the best all around reducer. Slow is for the warmer temperature range where you need the solvent to evaporate slowly so the paint has time to flow out flat before the solvent evaporates.

Put on the shoot suit, turn up the fans, wet the floor of the booth, if you have access to a down flow booth this isn't necessary, if not wet dust on the floor will billow up when you're spraying the lower sections of the car. Even though your just spraying the jams and recesses today, wipe the whole car down with a tack rag including jams and recesses. This sticky cheese cloth will pick up any dust and lint that settled on it.

Mix the paint, ratio on the can indicates 2:1 with reducer. Only mix what you plan to use, in this case a pint after mixing will be enough. Stir it up well and using a paint filter pour the paint into the paint cup. For jams and recesses use a very short swing, remember the gun has to be moving when paint is spraying. Tight spots like the doors hinge pocket get a super brief pst, pst, pst, of paint as your wrist moves the gun back and forth only a couple of inches. You want base coat to go on dry, especially with metallics, so cut the paint delivery back on the gun to just above minimal levels. Spray with a separation distance of about 12-14" and as indicated the gun must be moving when your applying paint.

Open the door all the way and spray as much as you can of the forward jam and hinge pocket. Paint the bottom and rear of the door, door sill and finally the body jam. Paint the inside of the fender lips, rear window edges, inside the marker light recesses, tail lights, up under the license plate area, t-top jams hood jams, hood edges and around the grille openings. Anyplace that is hard to reach or at an awkward angle should be considered, I painted the headlight edges and side vents too. What I am trying to accomplish is to spray the areas that are hard to spray, the ones that require the gun to be at oblique or odd angles to get coverage. These are the areas where runs and sags are likely to happen, the last thing you want when spraying the flatter panels of the body.

Spray on a light first coat, this is called a tack coat, the intent is to get only enough paint on the car to make the surface sticky. This first coat will flash off in about 10 minutes. Apply a thicker second coat and allow that to flash off (15 minutes). Apply your final full coat and allow that to flash off. Flash times (time between coats) vary, read the paint can. For solid base coat colors this coverage should be sufficient for all but the lighter pastel type colors, for those add another coat.

For the final coat of metallic base paint only you're going to spray from 18-24" and fog the final layer of color on there. Try to come at it from as many odd angles and patterns as you can, keep it dry. Some areas will be limited but do the best you can. This will even out the metallics and eliminate the potential for other problems associated with shooting metallics. Once you're done clean the gun and wait at least an hour for the base color to flash off, you want all the solvent out of the color before spraying clear over it.

Mix the clear at 2:1, high solids clears tend not to flow out as well as expected. I usually add 10%-15% reducer to the clear depending on temperature, 15% on warmer days. This allows the clear to flow out better. Mix about the same amount of clear as you did base coat. Strain it into the gun. Apply the light first tack coat, only light coverage is desired. It will flash off in about 15 minutes. Spray the first full double wet coat, wait 1/2 hour, spray second full double wet coat. This will be sufficient clear for jams and recesses. Clean the gun. Clear needs more flash time, as you build coats extend the flash time. The curing of clear is a chemical reaction between clear and catalyst. This reaction gives off gas, if you spray over a coat that is still degassing it results in tiny pin holes the gas makes as it continues to escape. When adding a third coat of clear, wait 45-60 minutes depending on temperature.


Tips:

Raising the car on blocks or jack stands can help you keep the gun square in the lower hard to reach areas. Another trick to do this is to rotate the cap on the gun 90* so the fan is horizontal, change your spray sweep to up and down.

Do not allow any material to dry in the gun, clean it promptly and thoroughly, remove the cap and tip, a short bristle brush works great, passages can be cleaned with a cleaning brush set from the paint store for just a few bucks.

Obviously you're going to have some over spray onto body panels. It's very common to get a run or sag either in the color or clear. Use a piece of 3/4" masking tape, place between thumb and forefinger sticky side out and place that right over the excess paint and pull it back off the car. This will lift enough material to make it easy to block flat again. Let what ever paint/clear is left to flow back out.

Follow the flash times, if you get impatient at this point you'll be taking steps backwards.

 

[7TRoadster]

Feather edge over spray

Because this car is being sprayed with fine metallic base coat paint it is necessary to block with 600 grit paper. Wait a couple of days to let the clear over spray from the jams set up. Block the car wet with the short blocks directly over the 400 grit scratches, a drywall sponge works really well at keeping water flowing while you block. Keep the surface wet and don't press down very hard, a light blocking is all that is needed. Wet primer blocks off quickly so only a few passes over any given area is needed, follow good blocking techniques. Block the whole car, takes about 2 hours. Scuff the recessed edges of the marker lights with fine (gray) scotch cloth but not the deeper parts of the recesses. Also scuff the lower halves of the tail light recesses, the exposed fender vent edges, wheel well edges and front grill edges. Give the over spray on the body a little extra attention, they need to contour into the primer seamlessly. You should not have blocked down far enough to expose any black. Fine metallics will flow across 600 grit scratches without showing the scratches. When completed rinse the car thoroughly with clean water, the drywall sponge works great here too. Blow out the cracks and crevices with compressed air and let the car dry completely.

 

[7TRoadster]

Feather edge over spray (2)

One caveat here, a fairly large one. You have blocked the edges of the clear to microscopic thinness. These super thin edges will react when you spray base coat over them producing small wrinkles called a 'curtain' for about 3/8" or until the clear is thick enough to resist the reaction. In order to prevent this the clear must be completely cured. Two weeks is a long time to wait to spray your final color and clear. Alternatively you can leave the car in direct sunlight for a few days. I use an infrared light/heater to heat those thin edges up and cure the clear. I get them to the point where you almost can't touch them (120* or so), then move the light to the next area. I let it sit for 24 hours after I'm done. Another trick that helps insure success is to warm up the area before you spray the base coat, just warm to the touch is fine. Move the heat source away, then spray a very light mist coat, the heated surface will evaporate the solvent before it bites into the thin clear. Flash time is like 2 minutes, spray another mist coat and let it flash off, repeat 4 or 5 times then move to the next area. Once you've done all the edges you can usually let them cool and spray your regular coats over them with no adverse affects. The dried base coat will prevent the solvents from reaching the thin clear. Yet another way is to spray the edges with a coat of water based primer and block with 600 after it dries. The solvent won't go through the water based primer and it doesn't react with the clear. A temporary mask is a good way to keep primer over spray off your newly painted edges.

Photo of Infrared Light

 

[7TRoadster]

Mask the Jams and Recesses.

Masking the door jams and recesses can be a challenge so take your time. You may have to rip it out and try again, I still have to do that sometimes too. We'll start with the door jams and work our way around the car. Use the soft line or back mask around the rear edge and along the bottom of the door, the tape should roll back about 1/8" away from the edge. Place the tape on the inside of the door as if doing a no line mask, then lay the plastic on the exposed adhesive side of the tape and pull it back and away from the edge until it's about an eighth inch away. Small slits in the plastic at the reverse curve of the door will allow you to tape the plastic down and follow the curve such that it won't pull away when you close the door. The front edge of the door only needs masking up about 6 inches, mask along the edge of the door seal if they were not removed and if removed under the door seal with a hard line mask.

 

[7TRoadster]

Mask the Jams and Recesses (2)

Mask the door jam on the body basically the same way using a back mask along the outside edge and pulling the tape back to the desired mask line with plastic. Again small slits in the plastic will allow it go follow convex curves. The door sills can be masked with a hard line mask both top and side.

 

[7TRoadster]

Mask the Jams and Recesses (3)

Once the jams are masked open the door fully and use the folded or gap mask along the front gap. Stick the mask to the inside of the fender and carefully tuck it inside as you close the door. If you hands are small enough you can also stick it to the inside of the door, mine are not, so I don't use that method.

 

[7TRoadster]

Mask the Jams and Recesses (4)

Once done close the door to match the body lines at the rear, the two sides of the tape rolled back tape will usually stick together in places holding the door in place and providing an even better barrier.

Rear door gap in photo

Masked the edges of the mufflers and tail pipes with hard line masks. Don't mask the marker light or tail light recesses other than a no line mask to fill the holes. The intent is to spray color and clear over the readily exposed edges and lower half of the tail lights but not the deep parts of the recesses already sprayed. Most of which are covered with light housings. Do the other door, door jam and gap same as the first. The open hole of the side vents and front grilles should have already been masked when spraying jams and recesses. Mask the side edges of the hood up to the hinge using a solf edge mask, lay the tape on the hood jam and roll it back about an eighth inch from the top. The hood in front of the hinges should already be masked with a no line mask. Carefully close the hood, the tape will seal off all but the edge of the hood jam from overspray.

 

[7TRoadster]

Spray Body Color

At this point it's really close, all the blocking is done, all the masking is done, what's left is cleaning and booth preparation. This is where nervousness tends to overwhelm the newer painter. All that work will be fugged up if I screw up the paint. If, if, if.... if my aunt had nuts she'd be my uncle.

While that is partially true it's not the end of the world. It's not like you have to completely start over, as we go through the layers of base coat then clear coat we'll cover interim fixes you can do that will help you achieve success. I offer this information not to show you how many ways you can fugg up, but to show you that if you do, you can recover. It's gonna happen, still does to me on occasion. It's best to know how to fix it so you can continue to learn and move ahead.

The cool thing about base coat is that you can work with it, if you get a run, sag, modeling, fisheyes, tiger striping or your air hose touches the wet paint. Let it dry an hour, block the area flat and give it another coat.

Run: a drop that runs down the panel. Remedy: pull off the excess paint with masking tape, allow to dry, block and respray.

Sag: a horizontal line of raised paint or clear where weight has caused the material to sag before settling. Remedy: pull off excess paint with masking tape, allow to dry, block and respray.

Modeling: Spots where the metallic base coat settles differently than in others. Usually because it's sprayed on two wet. Remedy: Cut back on the amount of paint the gun is delivering, let flash off and spray again.

Fisheyes: Small circle surrounding a contaminate that repels paint. Remedy: Remove the base coat with lacquer thinner, let flash off, clean with wax and grease remover, blend the edges with 600 and spray again.

Tigerstriping: Rows of metallic modeling caused by to wet an application of basecoat. Remedy: Cut back on the amount of paint the gun is delivering, let flash off and spray again.

Dust Nibs: They are inevitable, your always gonna have a few. The good news is that they are small and in most instances do not show after the clear is cut and buffed.

Insects: Carry a pair of fine tweezers to carefully lift them out of whatever they light in.

Cured Run: A run or sag not seen until the paint has flashed off. The biggest issue with these is that you will block through the adjacent areas before you get the run blocked flat. Remedy: Lay pieces of masking tape along each side of the raised area. The block will ride on the tape and block the high spot flat. Use 600 paper wet, you may have to replace the tape a few times. Once the high spot is off you can remove the tape, block flat and spray again. If your using base coat clear coat you need to inspect the base coat carefully for issues before applying clear. You can't repair the base coat after clear is applied, you'll have to spray that whole panel again.

Repair of runs and sags in single stage paint or clear are a little different, we'll cover those later in the cut and buff section.

 

[7TRoadster]

Spray Body Color (2)

Wet the floor, turn the fans on and put on the shoot suit. Wipe the car down with a clean mico-fiber rag then with the tack rag. Use very light pressure when using the tack rag, you don't want the sticky stuff to rub off on the prepped surface.

The technique for spraying body color is the same as spraying the jams, the sweep areas are of course much larger and require a certain amount of concentration to keep separation distance, speed and paint application consistent. Mix the paint, ratio on the can indicates 2:1 with reducer. Only mix what you plan to use, in this case mix about 48oz (3-16 oz cups) of paint. If not sure try to mix less than what you need, you can always mix up a little more if needed, you can't unmix it. Stir it up well and using a paint filter pour the paint into the paint cup.

Spray on a light first coat, this is called a tack coat, the intent is to get only enough paint on the car to make the surface sticky. This first coat will flash off in about 10 minutes. Apply a thicker second coat and allow that to flash off (15 minutes). Apply your final full coat and allow that to flash off. Flash times (time between coats) vary, read the paint can. For solid base coat colors this coverage should be sufficient for all but the lighter pastel type colors, for those add another coat.

For the final coat of metallic base paint only you're going to spray from 18-24" and fog the final layer of color on there. Try to come at it from as many odd angles and patterns as you can, keep it dry. Some areas will be limited but do the best you can. This will even out the metallics and eliminate the potential for other problems associated with shooting metallics. Once you're done clean the gun and wait at least an hour for the base color to flash off, you want all the solvent out of the color before spraying clear over it.

 

[7TRoadster]

Spray Body Clear

For base coat clear coat there is a window of adhesion, if you wait beyond the window you'll have to sand/scuff and spray base again. The can says clear can be sprayed up to 24 hours after the base coat and still will achieve chemical adhesion. My experience is that much better adhesion can be achieved by spraying clear after 1 hour minimum and before 12 hours maximum.

Mix the clear at 2:1, high solids clears tend not to flow out as well as expected. I usually add 10%-15% reducer to the clear depending on temperature, 15% on warmer days. This allows the clear to flow out better. Mix about the same amount of clear as you did base coat. Strain it into the gun. Very fine spray atomization is desired for top coats. Set your gun up so that it produces the finest mist possible. Every gun will be different so experiment by spraying a fan into the air, increase air pressure at the gun and try again, as you adjust material volume (bottom screw) and air volume (top screw) your goal is to find the setting that produces the finest material droplets the gun can produce while maintaining a good spray pattern. The better guns do this without to much effort. Others of lesser quality may not have the ability to produce as fine an atomization and usually results in an orange peal finish. You can add more reducer to help it flow out but be careful, the trade off for thinner paint is that it is more susceptible to runs and sags.

Wipe the car down with the tack rag, as you do look for anything that will impact the overall quality of the paint. Fix everything you see before applying clear.

 

[7TRoadster]

Spray Body Clear (2)

Apply the light first tack coat, only light coverage is desired. It will flash off in about 15 minutes. Spray the first full double wet coat, wait 1/2 hour, spray second full double wet coat. Clear needs more flash time, as you build coats extend the flash time. The flash of clear is a chemical reaction between clear and catalyst. This reaction gives off gas, if you spray over a coat that is still degassing it results in tiny pin holes the gas makes as it continues to escape. When adding a third coat of clear, wait 45-60 minutes depending on temperature. Clean the gun immediately after the last coat is sprayed.

 

[7TRoadster]

Curing Time

Remove the masking while the paint is still semi soft, usually about 12 hours after painting is about right. Always pull the tape back over itself and away from the finished edge when removing hard line masks and back masks. Be careful and watch for any material that doesn't separate cleanly as sometimes thickly painted areas can pull paint from unintended surfaces. If you see overly thick material along the edge of the tape use a sharp knife to lightly score along the edge of the masking tape before removal.

Cut and buff is next but you want the top coat hardened before you begin cutting. Cutting when the topcoat is to soft will usually cut to deeply into the topcoat. Wait a few days minimum, a week is preferable. Give the topcoat time to harden, it will take a month or so for the topcoat to fully cure but it is 95% there and can be cut safely in a week. If you can leave it to bake in the sun even better.

 

[7TRoadster]

Cut and Buff

Decision time

So your car is painted, the money on materials mostly spent, the results should and will likely be above average. If it flowed out fairly flat and suits your expectations you might decide to drive it as is. Most daily driver cars, like the ones you buy off the lot will have a slight orange peal to them. Orange peal is a common name for a topcoat with material droplets that didn't flow out completely flat after they hit the surface. Humidity, temperature, material mix, spray gun and the actual application disciplines all play a part in how the topcoat flows out. All of these things have to be almost perfect to get a topcoat perfectly flat without cut and buff so don't feel bad if your end result has some orange peal to it. Orange peal is most visible under fluorescent lights, roll the car outside and to the casual eye it will magically disappear. No so much on single stage colors but almost always on base/clear coat. The trained eye on the other hand can tell if a car has a flat or orange peal surface. Basically the reflections of self, trees or what ever else might be around has dulled edges. Where a cut and buffed car will have crisp edges to reflected objects.

The only production cars that I know of that are actually cut and buffed are the Bentley's. Most the high end cars are painted in perfect conditions with computer controlled application robots. The resulting finish is near perfect. Obviously this isn't practical for the regular painter. There is a negative side to cut and buff, in certain areas it's fairly easy to buff down through paint to primer. The implications are obvious. I'll cover the dangers in the cutting and buffing sections coming up but for now you need to know the potential exists. Weigh that when deciding to cut and buff or not.

You need to decide if the topcoat you have is adequate for your needs. If this car was a daily driver, susceptible to rock chips, road hazards, door dings, bird droppings, road grime, tar & kids, I would say drive it as is. I consider the paint and clear on this corvette to be pretty good. The paint came out really nice, the fine metallic came out evenly applied with no modeling or tiger stripes. The clear is better than average but has some orange peal in it. This customer wanted a paint job he could show on occasion so the decision was easy, this car will be cut and buffed.

 

[7TRoadster]

Cut and Buff (2)

The Cut

Cutting is a wet blocking of the finished top coat. The intent is to flatten the surface of the topcoat. You can cut single stage solid colors and clears. You cannot cut single stage metallics, it will ruin the paint finish.

You will need some 1500 grit paper, a short hard and soft sanding block, a sponge or spray bottle, squeegee, dish soap and some microfiber towels. I've tried cutting with water sanders but it's just to easy to go to deep to quick. Roll the sander up on an edge by accident for just an instant and you get to repaint. Best to use blocks and elbow grease.

WARNING: Do not cut edges or allow your block to roll over an edge. Paint and clear flows off the edges when applied and it will be very thin. You can carefully cut and buff right up to the edge but stay off the edge proper. This is important, pay attention and be careful.

First up use the dish soap and water to give the car a bath, wash all the dust off that collected while it was curing. Wipe it down with a microfiber towel. Dirt or grit under the fine grit paper will leave relatively huge gouges in the paint. It will feel like something rolling under the block, get it out off of there as soon as you notice it. Put clean water in the spray bottle or bucket and add a few drops of dish soap. Wet the surface and block small areas, use the squeegee to remove the water, use light reflection to notice the high spots will turn dull. Block a little more, squeegee again and the area will turn mostly dull with tiny shinny spots visible in the light reflection. Continue only until the shinny spots are gone and move to the next small area.

Use the hard block in the flat areas and the soft block in the curves. The soft blocks I use have round edges that help in contour transition areas. It usually takes me about 12 hours to fully cut a car. Take your time and stay off those edges. Your done cutting when the whole car is dull.

Tips:

Moving around the car from spot to spot use a tack rag to remove any foreign material before you begin cutting that area.

If you drop the sand paper, rinse it completely off in a sink or with a hose before using it again.

Change the water in your bucket often

A drywall sponge works great and is fairly cheap.

Photo of cutting materials (minus the dish soap, I figure you know what that looks like).

 

[7TRoadster]

Cut and Buff (3)

The cut progresses, front surround and rear top panels are done. Quarters, doors and fender sides not done. You can see the difference in the finish one dull, one shinny.

Your cutting along and suddenly an unseen run or sag shows up under the block. In order to fix this, you need to make sure it's thoroughly cured, I use the heat lamp to cook it as previously described. The biggest issue with these is that you will block through the adjacent areas before you get the run blocked flat. Lay pieces of masking tape along each side of the raised area. The block will ride on the tape and block the high spot flat. Use 600 paper wet, you may have to replace the tape a few times. Block carefully, you want to block the smallest spot possible flat. I have a 3/4" x 1" x 2" hardwood block I use for this. Once the high spot is blocked down you can remove the tape and lightly block it flat with the adjacent area. Now switch back to your 1500 grit paper and sand the area smooth.

 

[The Torch]

I wish I had all this info 25 years ago. It would have made the learning curve a whole lot shorter

 

[7TRoadster]

Cut and Buff (4)

The process of cutting is done. Taking my time and being careful pays off in that there are no busts through the clear. Yea!!!

Photo of car with cut completed.

 

[7TRoadster]

Cut and Buff (5)

Buff Stuff

There is probably less to learn about buffing than applying paint but no less critical to results. The buff is historically done in three stages, compound, swirl mark remover and polish. The Presta materials I use are changing that with a 2 step version. A quick cutting compound and a combined swirl mark remover with polish. Results are good, cleans up with water and saves time.

Materials shown below

Buffers and pads, compound, swirl mark remover/polish, microfiber rags, cleaning tool, shop shades and a spray bottle.

I have two buffers, a larger variable speed for general use and a smaller 3" for tight spots or close work. The smaller one is pneumatic so it needs a way to limit speed. I used an air valve off an old spray gun but any type of inline valve or regulator would work.

 

[7TRoadster]

Cut and Buff (6)

Buffing techniques

The wool pad is used for the compounding, the medium foam pad for the swirl mark removal/polish on two stage system and a white foam pad for polishing. I run my large buffer at roughly 800 rpm to do compounding. About 1000 rpm for swirl mark removal and about 1200 for polishing. Apply compound sparingly to a small area, start the buffer spinning before you touch the surface with it. Let the buffer pad slide into the compound working it back and forth using one side of the pad with moderate downward pressure. It's not necessary or desired to dig the edge of the pad into the paint, keeping the opposite side 1/2" off the paint is enough. Keep the buffer moving at all times. Raise the buffer off the surface before letting off the trigger. WARNING: Stay off the edges, it takes less than half a second to burn through an edge. As you buff the resistance creates heat, there is a potential to burn the paint surface, keep the buffer moving to limit heat build up.

Let's consider edges for a minute, assume we are buffing a fender. The edge runs the length of the fender along the top outside corner. The buffer spins clockwise, as you approach close proximity to a top edge make sure you're buffing with the right hand side of the spin so it buffs away from the edge. If you're buffing the side use the left hand side of the spin so it spins away from the edge. Never use the side that would be spinning into an edge, you'll burn through the paint so fast it's almost impossible to prevent. Compound right up to the edge with the buffer pad spinning off the edge. Do Not angle the buffer such that you actually compound the edge, you'll be sorry.......

As you work the compound back and forth you will notice the surface become shinny again. The dullness from the cut being compounded smooth, use light reflection and look for scratch marks to determine how much compounding is necessary. Keep working the buffer back and forth using only one side of the pad. As you work you'll notice the compound drying out, use the squirt bottle to dampen the pad, continue buffing until your satisfied with the surface finish. Add compound as the effectiveness of the operation decreases. Clean the pad when the buildup on the pad gets 'sticky', the compound and paint removed from the surface will stick to the pad. Eventually enough of it sticks to make the pad harder to slide around, sometimes it will even reduce the RPM of the buffer or becomes hard to control. Take the pad cleaning tool and with buffer spinning run it across the surface of the pad a few times.

Move to the next small area, apply compound and buff. Repeat, Repeat, Repeat..... Eventually the car gets done, it takes 12-16 hours to compound an average size car. Use the small buffer in tight corners or in areas the larger buffer cannot fit into safely. Once the compounding is done you should be left with a smooth shinny surface but it will have swirl marks left from the compound. On nice thing about Presta products is they clean up with water. Do this between each step, removing dried compound from door, hood, jams and seals where splatter tends to gather. Some of the other compound materials are not water based and very hard to remove if you let them dry on the edges.

The second step will remove those marks and polish the surface. Remove the compound (wool) pad and attach the medium foam pad to the buffer. Swirl mark removal and polish goes much quicker than compounding, I can usually do a complete car in about 4 hours. For polish (if a separate step) use the softest foam pad.

At this point the car looks great, surface is polished and reflections are consistent. The temptation is to give it a good coat of wax. The trouble with that is the top coat in ambient temperatures will continue to cure for about 6 weeks. Wait at least that long before sealing the surface up with wax.

Photo shows part of the hood buffed, the difference is obvious.


Tips:

In tight areas slow the buffer down to better control the spinning pad.

Keep the pad spinning and buffer moving at all times. Remember the pad rubbing on the surface creates heat, letting it stand in one place will potentially burn the paint.

A soft bristle tooth brush and water works great to remove material from body seams and crevices.

Throw the cord up over your shoulder when leaning out over the car. Keep the cord off the finish as much as possible. I use a carabiner to latch the cord into my center rear pant loop.

Stay off the edges, although you can usually get away with a quick touch of polish a quick touch of compound is big trouble.

 

[The Torch]

Using a carabiner is a good idea. I need to remember that one