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Old 12-01-2018, 10:13 AM   #61
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Thanks for the contribution. I have and use some small hard wood ones that I have made over the years for specific applications. Sometimes they really help.

I'm thinking that a 5.5" tear drop might be really useful. What are you using to cut them with. Table saw, band saw, wife's sewing scissors?
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Old 12-02-2018, 01:07 AM   #62
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Finish the Glass (6)

Photo shows the materials and tools (blocks omitted) needed to apply fillers and finish contours. Filler pallet, 1-1/2", 3" and 8" putty knives. Card file, scotch cloth, shop towels, panel adhesive (filler), spot putty, 3/4" masking tape, dish soap, lacquer thinner, wax & grease remover and mineral spirits. Two grits of sandpaper 100 and 220. Sticky back long board rolls are the most efficient as you don't have to cut sheets, hold or clamp the paper to the block.

Quite a few of the shops around use the plastic filler spreaders, they do work. I keep them around for when I need to fill a curve that the putty knives can't. It's my experience that the filler spreaders will leave more filler on the surface, quite a bit more in larger fill areas. More filler, more blocking to contour, I choose the route of less blocking.


The first step is to properly clean the glass, give it a bath with dish soap & water. Then go around edges and corners with the mineral spirits to kill any of the stripping residue. This was done once after the stripping but you will catch places that were missed the first time. Wipe off the edges of headlights, fender lips, window edges, door edges, t-top edges, basically anyplace the stripper dripped or could seep around. When done with this wipe down with liberal amounts of wax & grease remover and wipe clean with shop towels before it dries. Last wipe it down completely with lacquer thinner and let it dry.

Now take your masking tape and go around the car using small pieces to mark areas that need filler. Take your time, use your hands to feel each panel for low or rough spots. Make mental notes on obvious large areas. I usually do two trips around the car, one trip below the body center line and one trip around above the center line. Once the spots are identified, it's time to prepare these areas for filler. Apply 100 grit (course) paper to the short block and aggressively scuff the areas to be filled. You want to give the filler something to grip to, sand down just into the glass fiber but no further. Try to limit the area of scuffing to the area filled but at the same time you don't put filler over any area that isn't properly prepped. Feather edge out past the area to be filled by roughly 10%. If you have identified small areas these can be sanded by hand, cut a strip of paper and fold the sticky sides together. Why 100 grit and not 80 or 120? As a course grit 100 is in the sweet spot, 80 grit scratches are deep and it often takes two coats of primer before they are filled. 100 grit scratches almost always fill with one coat of primer. 120 grit scratches IMHO aren't deep enough for good filler adhesion.
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Old 12-02-2018, 10:33 AM   #63
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Finish the Glass (7)

As with resin, mix up small batches of filler as you'll only have 5-7 minutes working time before it begins to harden. Unless you have an unusually large area to fill, a gob the size of a golf ball is about right. Plop that down on the filler pallet and add the hardener cream. You only need enough to slightly change the color, for a golf ball size add about 1/2" out of the tube. Mix this together thoroughly using the thin putty knife to scrape filler off the pallet and fold it over what is already mixed. Do this as quickly as you can, use the next larger putty knife to scrape off the small one and add that back into the mix. Once the two parts touch the chemical reaction of hardening starts immediately, you have 5-7 minutes before it becomes unworkable. Using the putty knife that is larger than the area to be filled scrape some filler off the pallet and apply it to the body. Try to get the filler in the center of the putty knife as it will spread wider as it's applied. Drag the putty knife over the prepped area, at about a 45* angle. Let the outside edges drag on the body to assist in setting the height of the applied filler. This is a real help if you're filling a door to match gap heights as one side of the knife will drag on the fender setting the filler height. Use the edge of the smaller knife to remove excess from gaps and bumper seams.

Spread it on as smoothly as you can, remove any excess around the edges. Smaller areas can be filled with the smaller putty knives. Use one knife against the other to gather left over filler into the middle of the knife for the next spot. Use the least amount of filler possible to fill the low spots, you want to leave it a little bit high but not much. The more you put on the more you have to sand off. Once the filler gets so thick you can't spread it, stop. Clean the tools by scraping off the excess, one knife over the other. Scrape the pallet clean too. A little lacquer thinner on a shop towel works great to clean the final residue. Use the edge of the putty knife to flatten or remove edges of filler that spill into door gaps or bumper gaps while it's still soft. It will be much harder to get that out of there after it hardens. Mix up the next batch and keep going until all spots are filled. Let the filler dry completely and cool down, takes about an hour.

Photo shows the rear bumper filler application and tags left on after filler was applied. More on this rear bumper area later......

Tips: You want to do filler work at the lowest levels of the substrate possible. Extra time here is warranted; however, your going to miss some spots. I'll show you how to fix those after the first primer makes them more visible.
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Old 12-02-2018, 10:50 AM   #64
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Finish the Glass (8)

Now sizing the block accordingly using course paper block the filler to contour, as you get down close to finish height switch to the 220 grit paper and feather edge to contour. You should not be able to feel where the glass stops and filler starts. The smaller spots can be blocked with only 220. Don't be surprised to see a low spot in any larger filled areas. The putty knife will often drag along enough filler to leave a low spot. Often it takes a second coat to bring these areas to contour. Scuff the low area with 100 grit before adding the second coat.

Tip: If you've applied filler to match a door/fender or body/bumper gap contour, apply masking tape to protect the unfilled side as you block filler to contour with course grit. Remove the tape when blocking to finish contour with 220 grit.

Photo shows the front bumper to fender contour with second coat of filler. If you look closely you can see the previous filler lines about the middle of the marker light recess.
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Old 12-02-2018, 10:59 AM   #65
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Finish the Glass (9)

The filler is applied and blocked, the body looks awesome. At this point you can really see the contours and should be able to see the potential of a fabulous finish. The surface is dull, the contours show up great but the smaller surface imperfections are hidden. Your eyes are playing tricks on you. Photo is of the finished filler blocking. Notice the upper rear corner of the door and quarter panel. The front edge of the door just above the body line too.
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Old 12-09-2018, 03:51 PM   #66
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Prep for Primer

Now it's time to scuff the whole car with 220 grit, this insures adhesion to the glass of the first prime. This is not a full blocking, nor does it need that, just a good scuff so primer will stick. No need to scuff the areas that were already blocked when filler was applied. Just be sure to do things like rear window channels, door and fender edges, marker and tail light recesses, door jams, clam shell jams, t-top jams, hood jams and any other place you intend to paint. These areas can impact the longevity of the paint job if the edges don't adhere to the substrate. Very common on cars that have trim masked rather than removed. Eventually the paint will peal up at the edge. I suspect you have seen what I'm talking about here. Although I didn't photograph these problems, this car had that issue in several places.

Blow the dust out the cracks and crevices with clean air, wipe the surfaces off with a clean rag....

I take for granted some of the materials used because they spill over from car to car. One of those has been the packages of new microfiber rags I keep on hand for paint work. They work great for removing primer dust from surfaces before spraying. I use new rags only, if you choose to wash and reuse these rags make sure you don't use fabric softener. The little dryer sheets contain some kind of silicone contaminate that causes fish eyes and yes the rags will spread them all over the substrate. You can probably guess how I found that out......

..... as long as the discipline of substrate cleanliness has been adhered to there is no need to clean again. If however the car has been sitting for a while since you finished up the filler work. Clean it again as you did before the filler. With everything clean it's time for primer masking.

Photo of rear prepped.
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Old 12-16-2018, 10:38 PM   #67
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Wow, from one "old man" to another, thank you so much for this outstanding post! And the timing is perfect as I am just starting the body prep on my 81. I have quite a bit of experience with metal bodies and am confident in my ability to lay down a decent paint job, but this is my first time working Corvette fiberglass (SMC). Amazingly, my 81 has a completely virgin body, original paint, no impact damage anywhere. The only area of concern is a 4" crack on the bonding seam, passenger side rear fender, just aft of the door handle. I have no experience repairing those kinds of cracks and would appreciate any advice. Also, my plan was to scuff sand the original paint, block and level where necessary, and then prime, paint and clear. But you have me thinking that maybe I should go down to the glass using your method. BTW this is a frame off resto-mod so the body is just a shell at this point, inside and out. I roll it around on a body dolly. Again, can't thank you enough for taking the time to post this!
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Old 12-18-2018, 06:50 PM   #68
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Zim,

Original paint has good adhesion in almost all instances. Applied in a controlled environment you can usually paint over it successfully unless it has spider webbing. The small cracks in stress areas, that look something like a spiderweb. I would block with 220 before priming and of course keep the substrate disciplines.

A seam failure can have a number of causes. Some oil or other contaminate on the glass before bonding. Adhesive that had dried a little too much before bonding, not enough adhesive in that area or sometimes stress (twists) in the panel itself can cause separations. The most likely cause is an impact, sometimes a slight one can separate seams enough to allow moisture into a crack, which can freeze and cause separation.

Inspect the rest of the seam (inside and out) carefully to determine if removal and application of new adhesive is needed. If a cause is obvious you can usually do a local repair. If not, it's usually best to remove, fit, align and reinstall the fender with new adhesive.

Just an old man's $0.02
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Old 12-18-2018, 10:47 PM   #69
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7TRoadster thanks, much appreciated. There is no evidence of any spider web cracks anywhere. Probably be a few weeks according to my schedule (still getting over chemo), but I think I'll sand/strip down to the crack in question and see what's really under there. I'll post a pic in a day or 2, especially if I find something weird. I appreciate you sharing your knowledge, really helps!
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Old 12-21-2018, 09:05 PM   #70
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Primer and Masking Materials & Tools

I use plastic for masking, a 12' wide by 300' roll is about $40 at the paint store. You will also need razor blades, respirator, dust mask, a roll of 1.5" and 3/4" masking tape. The plastic I use is paint on one side only, the dull side will allow paint/primer to stick, on the shinny side paint will peal off. Make sure you always put the dull side up or if you prefer the shinny side down. If you forget flakes of primer will come off and scatter into your second coat of primer. Trust me in that you will not be happy, use a pair of fine tweezers to remove them. You can use masking paper but IMHO it takes longer and requires more material expense to complete.

Primers are a hot topic among painters, they are passionate about their favorites and can expound volumes of why one is better than the other. I've used quite a few of them on different projects over the years. Epoxy is a must over bare metals, it sticks like glue, has good sanding qualities, but it is almost twice the price. On fiberglass I prefer 'Feather Fill'. It's polyester based so it has the same expansion and contraction characteristics as fiberglass, it's catalyst based, dries to hard eggshell type surface, is easy to block, doesn't clog paper and is reasonably priced. I've had good luck with it over the years, I used it on my own car. From this point on all products applied have to be catalyzed (use a chemical hardener). In this instance we will apply black 'Feather Fill' as a base primer and gray "Feather Fill" as a finish primer.

Do not mix catalyzed primer and non catalyzed primers, not even for touch ups. I have seen strands of glass raise up through non-catalyzed primers and paint. You wouldn't think this is possible but it is, happened on a repair done to an '85 Corvette. Also do not use regular rattle can primer, PERIOD. Rattle can primers have a different formula that isn't compatible with most automotive topcoat paints (I don't know about water based color, maybe someone with that knowledge will contribute). It's fine for primer on patio chairs you intend to paint with rattle can paint but not suitable for substrate application on cars. If you have applied it, strip it off because it's very likely to react and wrinkle underneath the topcoat.

Polyester glazing putty is used to fill small defects. It is very fine texture and blocks easily. It's catalyzed and can be used over prepped areas as needed. Guide coat is applied as a fog and is used for visual identification of high and low spots. More on this later on in the primer blocking portion.
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Old 12-25-2018, 10:53 AM   #71
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Masking & Primer

I use the 1.5" tape to mask the edges of the area I want to mask. In this instance the hood jams, door jams and t-top jams will be painted. As such they have been stripped, prepped, cleaned and are ready for masking. I removed the hood latches and support, used a 3/4" x 1" wood trim board to hold it up. Place the masking tape under the hood jam about 1/2", press the tape up to stick it into place. You should have about an inch of tape, sticky side up extending into the engine bay. Do this for the whole engine bay and the underside of the surround in front of the hood hinges. Now cut a piece of plastic slightly larger than what you need. I tend to cut the shorter distance off the roll and unfold to length. In this instance I cut about 4' off the roll and unfolded it to full length. Dull side up slide the plastic down windshield and the center of the engine bay and under the hood, carefully without touching the tape.

Start at the base of the windshield and lay the edge of the plastic on the tape. It will stick as soon as it touches so be careful to align as best you can, don't worry about any plastic overlapping the jam. Now go to the other side and pull the plastic snug and lay it on the tape. Working side to side as you move forward lay the unfolded plastic on the tape. Pull it up under the hood, spread it out and lay on the tape under the surround. Now go back and trim the overlap off with a razor blade. Be careful not to cut the tape. If you do, place a small piece of 3/4" mask over the cut. I used the same piece of plastic to extend up over the windshield to the rear of the t-top area. Masking the edges of the windshield with scraps from the trimming.

Door jams are done the same way, placing 1.5" tape around the interior of the glass and laying plastic over the tape and trimming the edges with a razor blade. Tape the two pieces of plastic together with the wider tape. The back glass was trimmed around the edges with 3/4" tape, it bends around corners easier. Then cutting a piece plastic to rough size, placing it over the window and taping the plastic to the window edge tape.

You want your plastic taught without stretching or poking holes in it. The issue to avoid is plastic loose enough to billow out and touch the surfaces you intend to paint. Murphy will step right up and wait until you get the first wet spraying of primer on there then billow out and leave a defect you have to sand out. If you do have one of those loose plastic spots, cure it with a strip of tape laid across the loose plastic.


Tip: A sheet of plastic from the roll about 18' long opens up and makes a great temporary car cover for keeping the substrate discipline and shop dust off the project.
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Old 12-31-2018, 11:52 PM   #72
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Painting Techniques

Cautions.......

Paints & primers are harmful to your health. Wear a quality respirator, period. 3M makes a good mask for about $45, it has a two layer pre-filter for particulate and a charcoal canister to absorb fumes. If you can smell the paint, replace the cartridges, I keep a new set on the shelf all the time ($24). When I use it I buy another and put it on the shelf. Usually you can get about 24 hours of spraying time from a set of canisters. Keep the respirator stored in a sealed baggie between uses, ambient air will shorten the life of the charcoal odor absorbing component. Make sure the mask seals around your face, facial hair often degrades the seal so contaminated air can get inside. You should seek another type of respirator if this is you or consider shaving for the duration of the painting project.

Catalyzed topcoats are going to dry solid where ever they wind up, including in your lungs. This will permanently reduce your lung capacity, unless you want to pack an oxygen bottle around the rest of your life which may not be very long, Wear a quality respirator.

Another word of caution is to clean your spray gun immediately after spraying catalyzed primers, if you forget or get busy doing something else you'll be buying a new spray gun. Once the primer hardens in the gun, you won't be able to remove it. This can also be a problem if your spraying a large area requiring allot of primer. Each cup full of primer will leave a layer of hardening primer in the gun, those layers build up and reduce the supply ducts in the gun. I spray about 48oz (4 paint cups) maximum through my gun before cleaning it, even if I am not done priming.


Definitions

My hats off to those who have picked up a paint gun and experimented with laying down primer or paint. There is allot to learn about spraying, the gun, spraying tip/nozzle sizes, air flow, viscosity, air settings, etc. As is usual for this blog I will attempt to communicate basic concepts. The secrets are practice and experience. Until you pick up a spray gun and try, the text here will be somewhat ambiguous detracting from the desired impact of actual learning. Some definitions will be helpful in understanding the presented information. Primer is the best place to practice techniques because if you mess up it only takes a few minutes after it's dry to block errors flat and try again.

Swing - Swing is the action of moving your arm over the surface back/forth, up/down and side/side, etc. Developing a consistent swing is easier than it sounds. It is a combination of quite a few of the defined items below. Start with the gun at about 45* from the surface to be painted, squeeze the trigger to the first stop allowing air (only) to exit the spray nozzle, as the gun starts to swing pull the trigger past the first stop to apply paint/primer, at the same time square the gun to the surface. Maintain a consistent separation distance for the whole swing, end the swing by letting off the trigger back to the first stop then as you angle the gun away from the surface still moving let off the trigger. You should never be applying paint when the gun stops to go the other direction, that momentary stop will apply too much paint to that spot and it will likely sag or run. The gun must be moving when paint is added to the swing and shouldn't stop until paint flow is shut off. A swing can be as short as a few inches or as long as multiple feet. If you watch some of the paint applications on 'Overhaulin' you can observe the painter walking down the side of the car while spraying. This is an advanced technique used for applications of transparent top coats like candy or pearl paint where overall consistency makes a critical difference in results.

Speed - Speed has to do with how fast you swing the gun. To slow will result in sags and runs, to fast and dry dull spots show up. Some painters can vary the amount of paint applied by slowing or speeding up the swing of the gun. I have found it easier to develop a consistent speed and vary the amount of paint applied by adjusting the gun settings. For me that is more consistent than speed variations.

Air Pressure (at the gun) - The data supplied with your paint gun will tell you what the requirements are. HVLP (High Volume Low Pressure) guns which are the norm now require higher volumes of air at lower pressures. The spray pattern will be greatly impacted when this runs above or below recommended volumes/pressures. Don't fall into the trap of reducing separation distances to compensate for low pressure or flow. If you match your swing lengths to panel lines you can usually stop and wait for the compressor to catch up then resume on the other side of the line. Big hoods, deck lids and roof panels can be a challenge

Consistency - If you have adjusted your gun to spray well at 10", then keep it consistently as close to 10" as you can while spraying. Spray with consistent air pressure, volume of paint, speed of swing, etc. This is hard to concentrate on as it needs to be done at the same time as the swing and watching the paint application.

Fade in/out - The part of the swing that transitions from applying paint to applying air only to shut off and back again. In some instances of touch up repairs it may be required to fade new paint into the old. I'm not very good at this so I will decline to pass on information that is potentially flawed.

Viscosity - Thickness of the primer/paint being applied. Thicker mixes will require different paint tips with different flow rates. Heavy primers use 1.8-2.0, a 1.4 is a good one for single stage paints and base coats, I use a 1.3 for finish clears and have a 1.0 in my touch up gun. Pay close attention to what you're spraying and what tip you're spraying it through. A mismatch causes orange peal, dry spots, runs, basically all the things a painter worries about. More on tip/needle sizes to follow.

Separation Distance - The distance between the air nozzle tip and surface to be painted. Consistency is the goal here, critical for metallic paints.

Overlap - That portion of the spray pattern that overlaps the previously sprayed pattern.

Atomization - The process of mixing liquid with air into tiny droplets for application (paint) or burning (fuel).

Paint Fan - The spray pattern of paint through the gun. The paint tip is the beginning of the fan and it gets larger the farther away from the gun it gets. At some point the droplets are to far apart to cover evenly. That limit is usually 12-14" depending on flow tip size and viscosity of the liquid. A few test shots on some cardboard will help allot in understanding the limits of your gun.


Paint Gun Basics

The paint gun has one basic purpose, to atomize liquid into tiny droplets capable of evenly transferring that liquid to a surface. Air pressure, viscosity, separation distance, overlap, speed, temperature, humidity all play a part. Getting everything perfect is still a goal rarely achieved. I keep thinking I'm getting closer but then Murphy comes along and I am left rethinking.

Putting a pressure gauge at the base of the gun is a good idea, you can then adjust the regulator to supply the correct pressure at the gun specified by the manufacturer. No guessing... Some painters put the gauge on quick disconnects as the gauge adds length to the handle that can often get in the way in tight spaces. Test the pressure, make sure it's correct then set the gauge aside and connect the hose directly to the gun.

Your paint gun typically has two screws, the top screw regulates air flow to the cap. Not enough air and you get a roundish blob of paint, to much air and it will spray a figure 8, correct adjustment sprays an ellipse 6-8 inches long. Different viscosity paints/primers will spray differently, understand these settings and adjust each time you change what you're spraying or after you have disassembled and cleaned the gun. A few test shots on some cardboard before spraying will help allot in adjusting for viscosity and spray pattern.

The bottom screw adjusts the paint volume stop or trigger depth. If you pull the trigger and adjust the second knob you can feel the trigger move. Screwing the cap in reduces paint application by stopping the travel of the cap pin. Unscrewing this knob allows the trigger to be pulled back further increasing the amount of paint allowed to flow through the tip. This is a seat of the pants adjustment, experience will help, I adjust the gun to what I expect will be thin coverage, hold the gun about 10" from the cardboard and give it no more than about a half second spray, typically coverage is thin because I adjusted it that way, I'll add a half turn of paint and test again. Once I have full coverage on the pattern I consider that a good starting point. It usually only takes me a couple of tests to get it close but I am accustom to the speed of my swing. The real test is applying paint to the panel, if it's going on to wet cut it back, if to dry open it up. Usually these are minor adjustments 1/4 turn or less.

How do I tell if it's to wet or dry? Dry is easy, the surface will be rough and dull. Much easier to go back over a dry spot that fix a run so for newbies try the dry side of application first. Wet is harder to tell because in most instances you won't notice it until it runs or sags. Watch the leading edge of the pattern (red square in drawing) as the paint hits the surface for ripples in the paint. If the air flow can blow small ripples in the paint it's to wet. I watch the paint going on every single swing to gauge the differences in pressure, viscosity and atomization. Good lighting is a must because the reflection of light is sometimes the only way to visually see the application. This is important, practice with the application of primer but pay attention.

Let's assume your pattern is 8" wide at 10" separation distance. You have a HVLP gun adjusted to spray at 38lbs. The first swing lays a 4" wide pattern across the top of the door, the other half is purposely sprayed off the door. The second swing should have the spray pattern centered on the lower edge of first (4" overlap), the third swing pattern is centered on the lower edge of the second, etc. This is called a double wet coat and is listed on most paint cans as the way the contents of the can is to be applied. There is also listed wait times between double wet coat applications. Doing what it says on the can rather than assuming you know or assuming the paint store counter guy knows adds professionalism to your work. You will make fewer mistakes; mixing, applying, waiting and in general using the materials to full potential. Temperature, humidity and thinning options are all listed on the paint can, match them as close as you can to your conditions.

if you don't understand what I'm trying to communicate please ask questions.


Gun tip/needle sizes

The tip/needle size of the gun quantifies how much paint or allows different viscosity paints to be sprayed. A general rule is that thicker liquids use a larger tip and thinner liquids use a smaller tip/needle size.

0.5-1.0mm, Generally used in detail spray guns they produce a much smaller pattern compared to full size guns. Used for thin dyes and stains as well.

1.2-1.3mm, Good for clears and thin base coats. Although it takes longer to apply the 1.2 tip sprays a very fine mist that flows out well. The 1.3 tip is generally recommended for clears and thinner single stage paints. It flows enough for a faster application with finer atomization.

1.4mm, Good all purpose size, works well with base coats, paints and high solid clears. This tip/needle comes as close to a universal tip as you're gonna get.

1.5-1.6mm, Versatile tips for base coats and single stage paints. Good choice for lacquers. Thinner paints risk orange peal because they don't atomize very well with these tip sizes.

1.7-1.8mm, The 1.7mm is not a common size but the smallest you should use for primers. Typically, the 1.8mm is used for most primer surfacers. If you wanted to spray a door with latex you could use the 1.8mm.

2.0-2.3mm, High build primers and other thick materials, these tips lay on a lot of material very quickly. Recommended for experienced painters.

Pearls tend to spray better on the smaller side of the tip/nozzle chart while metal flake or metallic paints spray better on the larger side of the scale. Mix a small bit of paint and try the different tip/needle combinations you have to see what works best with what you're spraying. Experience really helps here, the only way to get that is to spray some paint, practice with primer.


Painting tips

Try to paint in panel sections, because catalyzed paints can dry enough to not flow together properly in the time you paint around the car and get to painting the other half of the hood.

Paint from the top down, do your edges and recesses first. You want those covered first so you don't have the over spray in the finish top coat.

Loosen the air cap and twist it sideways to paint low areas, this allows gravity paint flow and a horizontal paint fan. Your swing will switch to up/down.

If you do get a run or sag, don't panic, lay a piece of 3/4" masking tape over the run and pull the excess paint off the surface. Shoot one light coat of paint over the impacted area and in most instances it will flow out. Metallic paints will likely require you to re-shoot that part or panel, but it's easier to block out a flattened run than one that isn't.

Sometimes a run can sneak by unnoticed. Lay masking tape on both sides and block it until flat, you may have to replace the tape a couple of times. Then remove the tape and block to contour. If you try to block out a run without the tape, you will sand through (clear to paint or paint to primer) on both sides of the run before you get it flat again.

Pack a pair of fine tweezers around in your pocket while painting for that odd insect that gets so high on fumes it just can't stay out of the wet paint. Seems like there is always at least one just waiting...
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Old 01-01-2019, 09:39 AM   #73
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Prime

The car is clean, it was cleaned before masking. Blow any dust off with air and wipe it down with a clean microfiber rag. Special note: If you use wax and grease remover after masking, make sure you stay away from the masking tape. The chemical in the remover will react with the sticky stuff on the tape and it causes fish eyes. Keep the wax & grease away from the masking tape.

The fiberglass on the corvette is a light gray. Black base primer is used because you need to see when you block through to the fiberglass. Apply a single double wet coat, jams, edges and recesses first, then the rest of the car starting at the top and working down.

Add catalyst to the primer one mixing cup at a time as you use it. I used 3 cups at 16oz each to prime the car. Practice your application technique as you apply the primer to the surface. If you have primer left over put it on the car in places you know need it, like over repairs, filler or rough spots.
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Old 01-01-2019, 09:39 AM   #74
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Prime

You will notice I have the t-tops removed at this point as the t-top jams are to be primed as well. The t-tops will get primed when the mirrors, headlight bezels, fuel tank door and front valence are primed.
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Old 01-03-2019, 12:44 AM   #75
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Prime, Block & Repeat

At normal temperatures primer will cure fully in 12 hours. Colder temperatures usually take longer. In the colder months I usually wait 36 hours. Prepped and primed the unattached parts during the wait.

Block the car with 220 grit paper. Take your time and use good blocking techniques. As you block you're going to discover small nicks, scratches, low spots, high spots, etc. Block them down until you can see the glass start to emerge through the primer. Mark that spot with a small dot of masking tape and move on. Trust me that the marking is necessary because you will never remember all the little places you find. If you used a putty knife, razor blade or scraper to strip the car you can expect to find hundreds of these small nicks. Remember that blocks don't lie, trust them and believe what they show you. First block on a corvette body is usually about 7 hours work.

Now you have the car blocked and these little pieces of tape here and there. More than usual on this car, along the repaired seam lines, places where filler had been applied and places around the new bumpers where new filler was applied. At this stage you can feel most of them and they are usually about 10 thousandths deep. The exception is the larger low spots on big flat panels such as the hood, doors, fenders or hood surround.

In the photo you can see small spots marked, places sanded down to glass and some larger low spots just below body line in the front half of the door.
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