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-   -   An Old Man's Guide to Painting a Corvette (https://www.digitalcorvettes.com/forums/showthread.php?t=292214)

7TRoadster 09-26-2018 12:26 AM

An Old Man's Guide to Painting a Corvette
 
I'm an old guy, been working on and painting cars for 40+ years. I don't profess to know the latest wiz bang tech, high output tools or even the latest in water based paint. What I do know is what works for me, that is what I intend to present here. Start to finish.

Here is a video of my results, you can decide if I am qualified and choose to continue reading or not: http://youtu.be/re0l3vRJhVI

The intent is to present a guide for preparing and painting your Corvette. Each step will be covered in depth and with known good techniques and products. They may not be the best or the most expensive, I just know they work because I have used them multiple times. There are as many different opinions on how to paint a car as there are painters. Tips are welcome of course; I'm quite sure most will be valid and provide excellent results; however, I cannot attest to the validity. The intent is to show how years of experience have taught me to obtain quality results. I hope this will help you plan, prepare, spray and finish a great looking paint job. It's not rocket science, a little practice with the right tools, quality materials and you to can achieve outstanding results.

OK, enough said about intent. Let's get going.



The Plan:

You will need a place or two to do the work. Time in the space is subjective to how much time you have to work on the car. Average time for me is about 6-7 weeks, working an average of 6 hours per day. The space must be well ventilated to allow a fumy mess or two, a place to store parts, a place to paint with excellent light and ventilation. Sanding dust and over spray will permeate the space too. Transportation to and from a paint booth or a suitable space to paint.

Tools and equipment need to be part of the plan too, air compressor, air dryer, regulators, air filtration masks, sanding blocks, spray gun(s), buffer, buffer pads, etc. Sometimes you can borrow tools, just be sure you return them with some form of compensation. Oh yea, a beer fridge is helpful too. :D

Materials are not cheap and it's best to plan for their purchase as part of the overall plan. This can be stretched out over the time it takes to move between steps. Depending on color, good quality paint can range from $200-$600 bucks a gallon plus the activator, $250 for a descent clear. Thinners, wax & grease removers, cloths, rubbing compound, abrasives, resins, fiberglass, filler, buffing supplies, etc. Plan on $1200-1800 in materials.

As a novice painter the most forgiving solution is a single stage paint in a solid color because it is much easier to repair if you make a mistake. Not many shops paint in single stage anymore. Base coat/clear coat is the norm, a coat of base color goes on dry, followed by shinny wet coats of clear. It's much easier to spray metallic paint in base coat/clear coat. It is less forgiving because you can't really touch up a small space without very advanced techniques. This is also true for single stage metallic paints. You will likely end up masking, prepping, repainting and clearing that part of the car. Yes, I've had to do that, but it usually it sets the project back only a day or two. Not a big deal in the overall scheme, nothing to be afraid of.

Here is the methodology I use to work through the process. Using the following steps, the tools and materials needed for each step will be covered as the blog advances in the process.

Prep for stripping (disassembly)
Strip the outside
Strip the door, hood and t-top jams or clam shell jams.
Body assessment
Prep for fiberglass repair
Repairing the glass
Sand glass to contour
Finish the glass and curing time
Mask & prep for primer
Prime
Block & prime, block & prime, repeat......
Mask & prep for paint
Spray body jams and recesses
Feather edge over spray
Mask jams and recesses
Spray body Color
Spray body Clear (if two stage)
Curing time
Cut and buff
Reassembly


Overall Assessment of this project:

The car represented in this blog is a 1978 Silver Anniversary Corvette. It has been repainted previously and the paint has deteriorated, poor adhesion has allowed the paint to separate from substrate as it shrinks with age. Stress cracks in the usual locations and a substantial mismatch in hood to fender alignment needs to be repaired/fixed. The factory bumpers are in good shape and match the body pretty well, not perfect but better than the replacements I've seen. I do not intend to remove them. Doors hinges are not sagging, they open, close and fit the body reasonably well, again I do not intend to remove them, although some gaps are poor and will be addressed. The owner desires a step above driver quality paint, but doesn't want the expense of the disassembly/reassembly necessary for perfect show quality. The color is metallic so base coat/clear coat will be applied in this instance.


Your assessment may be different, your car may be already apart, need substantial fit and alignment work, rust repair, body mount replacements, etc. Those items fall more under a total restoration plan than a painting plan. Right? Therefor some assumptions are in order.

Your paint is only as good as the substrate (surfaces below paint), uncontaminated substrate is critical to adhesion, reducing blemishes and good long lasting quality. I will refer to substrate concerns often in the coming posts, pay attention as this is crucial information. This assumption is that proper discipline has been applied to substrate preparation.

Consider weight when deciding if your body is ready for paint. For instance; engine & transmission weight will change the frame to body relationship, in extreme cases doors that fit perfectly without the engine installed might have to be readjusted or have gaps refit. This is not something you want to discover after the car is painted. The assumption being the body was fitted with weight on the chassis.

If you are considering painting your car, it must be assembled and body adjusted as close to specification as possible. If sagging door hinges or misaligned body panels exist they must be addressed before considering paint. Here the assumption is you are starting on a solid foundation.

Body mods such as fender flairs or hood scoops are fitted and installed. Air dams, valences, ground effects, fitted and removed. The assumption here is that all body additions are fitted and mounting holes exist before the painting process begins.

Any existing body repairs are stripped down to glass and rebuilt using proper materials. C3 Corvettes are constructed with polyester (poly) based resins, therefor poly resins, filler, primer and paint are used to get expansion and contraction rates as close as possible to eliminate the chances of ghosting (1) when the car is exposed to sudden temperature swings such as parking in direct sunlight. You cannot trust that filler used previously is polyester filler. The assumption is that proper repair materials are used in all repairs.

(1) Ghosting is the odd shaped lines under the paint that appear and disappear with temperature changes. These are caused by different expansion and contraction rates of the substrate materials used.


Next Post: Prep for Stripping

gtr1999 09-26-2018 05:54 AM

Nice job, I will be watching- and learning.

PS the vette looks great, I really like the strip setup.:thumbsup:

Metalkid 09-26-2018 11:03 AM

The car represented in this blog is a 1978 Silver Anniversary Corvette.

Fabulous! That's what I have, with original, (badly in need of a refresh) paint. Can't wait to learn how to do it right!:partyon:

7TRoadster 09-27-2018 12:08 AM

Preparing to Strip Paint
 
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Preparing to strip is pretty basic, normal hand tools are needed with one exception. Bagging and tagging parts is highly recommended. It takes a few seconds to throw screws in a baggie and write a location on the bag. Knowing what screws go where and what parts are left and right during assembly saves tons of time, plus sorting through a coffee can of bolts and screws isn't my idea of fun. At my age B&T is a requirement as I can't remember where all the screws came from without the notes on the baggies. Even more so after a couple of beers........ :D

Removed all the emblems & scripts, front grilles, plates, all 4 marker lights, tail lights, antenna hole trim and rocker panels. The fuel door and hinge was removed, then separated so the door itself can be stripped. The front valence is also removed as stripping upside down is a PITA.

Removal of the door handles and locks require the inside door panels be removed. The handle removal is made much easier by removing the 3 door latch screws in the door jam and letting the latch hang down inside the door. This allows just enough room to get tools inside for the handle and lock removals. Attach the latch with the 3 screws when done. The window has to be down to remove the outer window trim (below), consider leaving it down so you can open the door when needed.

The outer window trim on the doors is removed by removing the 4 screws holding the inner stainless on, to do that you have to remove the ends of the door seals and pull them up and out of the way to expose the access hole for the end screws. The other two are centered just at the front and rear of the window edge. With all the screws removed you can pop out the push buttons and remove the trim pieces.

The rear window trim also has to be removed, there is a special tool needed. There are different designs, mine is the one in the photo. The tool isn't expensive and can save you the cost of the window should you decide to try removing the trim with your favorite screwdriver. Ask me how I know..... Summit has them for $11 https://www.summitracing.com/parts/o...iABEgLrqPD_BwE

If you have T-tops mask the stainless edges to keep from scratching them during the actual stripping. If you have a convertible remove the rear bow anchors and the rubber bumpers on the front of the clam shell.

The car then is bare of all the external bling and parts not intended to be stripped. The video shows the car ready to begin stripping.... https://youtu.be/tAHGEhXE-sQ


Next Post: Stripping the Paint

7TRoadster 10-02-2018 10:13 PM

Removing the Paint
 
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Let's start this post talking about safety. The paint remover I use is some pretty bad stuff, it's smells awful, will burn bare skin, damage your eyesight and a concentration of fumes can be FATAL......... I hope that got your attention. I use Aircraft brand paint remover, it's strong stuff, made to remove even epoxy paints and primers. The down side of using such a strong product is that it has many ways to harm you. READ AND FOLLOW THE INSTRUCTIONS and CAUTIONS. Use only in a well ventilated area, wear eye, skin and respiratory protection. A dust mask won't work, you'll need a respirator. Most automotive paint stores have them for under $40. No excuses, do it and be safe.

There are several types of this product, there is one specially formulated for fiberglass (pictured). The fiberglass version has less toxic fumes and won't bite the glass. It is also less effective and takes longer to achieve results than their regular paint remover. The regular remover, in very small print at the bottom of the instructions, it says that it is not recommended for use on aircraft, fiberglass or flexible surfaces (rubber bumpers). I struggle with that given the name and photo on the can. The major use of paint removers is for removing finishes from surfaces that can be damaged by sanding. My interpretation of those statements are that they are legal disclaimers, basically use at your own risk. The same use at your own risk statement has to be applied to this blog as well, use of the materials I choose is your choice. Only the manufacturers warranty applies, I have no control over how the product is used and assume no responsibility for the products application.

I've personally used the regular paint remover on quite a few corvettes, even my own and never had a problem with it biting into gel coated glass. If you call the manufacturer they will tell you it pits fiberglass, that has not been my experience, although I have had it bite into previously repaired glass. The heat generated by the remover can warp your flexible bumper so keep it off of that. If you have any concerns about it, select the fiberglass formula product. They also make a product specifically for the flexible bumpers. C2 note: (Right around the time the C3's first came out the fiberglass resin used in Corvettes changed from SMC type to Polyester type resins. I haven't used the regular remover on SMC type glass and therefor cannot attest to results). Testing a small area or previously damaged area is recommended before overall use.

The photo shows what your going to need, but not how much of it. That will depend on how many coats of paint are on the car. If it's lacquer, enamel, acrylic enamel, urethane or any of the other types of paint and primers they used over the years. Respirator, safety glasses, chemical resistant gloves, lacquer thinner, steel wool, filler spreaders, disposable containers, drop sheet, disposable paint brush and of course the stripper. I prefer Redheads...... :D

The actual removal is pretty straight forward. Slather on the remover, wait until it bubbles up & scrape it off. But why remover in the first place? Why not stand it off or use a heat gun and scraper? Experience has taught me that the extra work up front stripping the paint off saves time over sanding it or scraping it off. If you choose to sand the car you would likely use a DA sander or an electric sander. You will not be able to hold the sander perfectly flat at all times. So that means you will be sanding in low spots all along the body surfaces. If you were to tip the edge a little bit to get to that hard to reach spot, that will really add to the wave pattern on the surface. Sanding inevitably goes down through the gel coated surfaces too, down to the bare fiberglass. This represents a substrate challenge in that now some places have gel coat others not. True that you can get spray on gel coat but that involves prep, spray, cure spray and peal steps in the process. When you get done you're still going to have a surface that looks like the rolling ocean. It will feel flat but it won't be. The low spots only a few thousandths deep will then have to be blocked flat during the blocking process. Heat and scraping is also a problem because heat softens the glass, the corners of the putty knife will gouge the surface, you'll end up with 5-20 thousandths deep scratches all over the car to block out.

I choose removers because when you get done the surface will be smooth and the gel coat on top undamaged. Fiberglass is wavy to begin with and it's hard enough to get it flat without adding the extra work sanding or scraping adds. With substrate being tops on my list of importance it pays to keep it as pristine as possible. That point comes into visual perspective pretty quick when you look at a stripped panel vs a scraped panel vs a sanded panel. Quality results can be achieved in all instances, it just takes more work IMHO to use any other method than stripping.

7TRoadster 10-02-2018 10:16 PM

Removing the Paint (2)
 
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So slather on the remover, wait until it bubbles up and scrape it off. The trick here is to wait as long as you can before the remover starts to dry. It may take you a few tries to get the timing right, so if it dries just brush over a light coat of remover. Use the filler spreaders to remove the old paint, you can push on them hard they won't hurt the glass, drop the scrapings into the disposable containers. Don't be tempted to use the putty knife even on the stubborn spots, no matter how careful you are you will gouge the glass. Add another coat, let the stripper do the work, be patient. This car has several coats of paint, clear, epoxy primer over old Emron type paint, plus the original paint under that. It's taking 7 coats of stripper to get down to glass. It's a worse possible case but with patience it's getting done. It will take at least a week to strip this car maybe 10 days, 3 gallons of remover, you get the idea. I've had other cars with original lacquer that stripped in two easy coats that took only a gallon to remover to finish. You just won't know until you start doing it.

As you get down to glass there will be a few stubborn places where the paint is really stuck on there. You can save some remover by scraping it off the thinner areas that have cleared and then spreading what you scraped off on the stubborn parts. Let it sit a bit longer. That thicker half dry stripper will continue to bite down into those stubborn spots, after 10-15 minutes scrape that off and if necessary add another coat to the spots.

When you get down to bare glass it will look something like the drivers side of this hood. Now use the lacquer thinner and steel wool to wash the surface, wipe it clean with shop towels. A little elbow grease will remove any lingering primer, the thinner removes the chemical from the surface and leaves a clean smooth gel coat surface on which to build your new substrate. The passenger side of the hood has been washed, I'm sure you can see the difference. I don't let the chemical from the remover sit on the glass for extended periods. I remove only what I have time to wash and clean in any one session.

The Torch 10-03-2018 04:31 AM

Thanks for the great write up so far but this should be in great big bold red letters!

READ AND FOLLOW THE INSTRUCTIONS and CAUTIONS

7TRoadster 10-03-2018 05:29 PM

Thanks Torch, done!!!

autowiz 10-03-2018 10:33 PM

We had a local legend in the auto body world, Augie do a few cars for us. He had his own business for a lot of years and sold it and came out of retirement for a few jobs for us. It kind of sucked having bodywork done in the shop because of all the dust it kicked up, but it was incredible to watch a real professional work. Augie did all the bodywork on this GTO: https://www.digitalcorvettes.com/for...d.php?t=241858


He also did a few c3 corvettes for us. He had a whole career and life behind him of working on these cars. He stripped the paint off of them with a paint scraper. It took time and made a mess but it left the fiberglass body and its gelcoat unharmed by chemical or rotary tool. All the gaps on his work were perfect. He took so much time but damn did it come out right. He used 2 paint sticks together to set the gap around the headlight doors. In raw fiberglass it looks like such a large gap, but he knew the paint would close the gap and while I hated his dusty work while it was in the shop, I now miss this great source of wisdom and skill.

7TRoadster 10-04-2018 11:03 PM

Removing the Paint (3)
 
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There are always surprises when removing paint, it's obvious (photo) the front fender has been repaired. More on this during the body evaluation section coming up. The paint remover will bite into the filler, the upper part of the fender will need to be re-contoured anyway so to save a little time I switched to a putty knife to finish the upper half of the fender. The lower half was scraped with the softer filler applicator, both halves washed with steel wool and lacquer thinner.

During this session, I smelled the paint remover coming through the respirator, a sure indicator the charcoal cartridges need to be replaced. So I stopped for the day, off to the paint store tomorrow to get new cartridges. Be Safe, pay attention.....

7TRoadster 10-04-2018 11:13 PM

Removing the Paint, Tip
 
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While removing paint you're going to discover some stubborn places that just don't want to let go. They are usually in those hard to reach places where refinishing will be a challenge.

When you see these, resist the urge to grab the putty knife and scrape them off. It only takes a small dab of remover and time to soften these up so they can be removed without damaging the surface.

:thumbsup:

7TRoadster 10-11-2018 09:27 PM

Removing the paint, tip
 
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Stripping this car is the toughest I've ever had the pleasure of dealing with. The reason is the thickness of the existing paint and a layer of epoxy primer (photo).

On top is a layer of clear, then a base coat of purplish silver, under that a coat of regular silver, under that a thick layer of red oxide primer, then comes the coat of black epoxy primer. Under that is the original paint and primer. Measures .020 thick.

The fiberglass formula of remover does fine down to the epoxy primer, but won't remove it. Switching to the regular stripper at that point takes 3-4 coats to soften and raise it up for removal.

When/if you run into hard material like this it helps to lightly sand/scuff the epoxy with 220 grit before applying the remover. This allows the remover to penetrate better.

The Torch 10-12-2018 04:42 AM

How would a blaster (dry ice or walnut shells - NOT sand) work for stripping?

7TRoadster 10-12-2018 08:01 PM

Honestly I don't know, never used them. It seems to me that anything hard enough to remove paint will likely pit or damage the fiberglass.

Below is an article on soda blasting that says it can be used by experienced people who know how to prevent it from causing damage to the glass.

http://www.superchevy.com/how-to/vem...soda-blasting/

7TRoadster 10-15-2018 11:59 PM

Removing Filler
 
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As explained above all filler is not the same. Corvettes need a polyester filler so it will expand and contract at the same rate as the glass itself. The photo in post 10 shows the fender with filler applied. I don't know what type of filler is on the car, how thick it is or what evils it covers. It must be removed.

So how do you remove filler without damaging the glass any further. It's not as hard as you might think. This photo shows the tools you will need. A heat gun, wire brush, gloves and a dust mask. (I use a respirator but a dust mask will work.)

The heat gun I use is made by Milwaukee and turns our a good bit of heat, the air will easily burn your hand. The fine SS wire brush is made by Lincoln (welding).

It's available here, link: https://www.homedepot.com/p/Lincoln-...H581/100341129


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