You have to be realistic when it comes to completing the bodywork yourself. Ideally, you or a single shop should do all of the bodywork, prep, priming and painting. If you choose a workshop, they can check the quality of the work and guarantee the results. Finishing the body in a workshop and having an owner participate in the painting in a paint shop are two scenarios that rarely work well. Bringing a finished, ready-to-paint vehicle to someone for painting is a tricky business. No painter wants to take a risk that someone else has done the body work and prep work correctly. It doesn't matter whether you or a specialist workshop carried out the work. Even if you tell the painter that he takes no responsibility and that the result of the painting is entirely your business, many bodyshops still hesitate because there are no guarantees.
This tech tip is taken from the full book "HOW TO RESTORE YOUR CORVETTE: 1963-1967“. For a comprehensive guide on this entire topic, see this link:
LEARN MORE ABOUT THIS BOOK HERE
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On the vent window, the vertical run channel of the door glass is fixed with an adjustment screw to control the in and out angle of the glass. It takes some turning and fumbling to remove the vertical barrel channel from the door with the adjustment screw installed, but it's well worth the extra effort. Typically the adjustment screw on the barrel channel is corroded, making it much wiser to take the assembly out and loosen the adjustment screw while it's on the bench to avoid breaking parts.
Let's face it, bodywork is an art that requires patience and feeling. You either have patience or you don't, and "feel" is something that develops over time. Experienced body shops have a feel for straight sheet metal. You may feel a rise or dip on what should be a flat surface. You can also feel if the putty has a noticeable transition edge from the repair to the surrounding sheet metal. Some of us can grasp this acquired talent quickly, while for others it may take years to fully master it, if at all.
If you're having trouble feeling the wavy panels, blocking will show you where the smudges are. Blocking refers to taking a long, straight block of wood or plastic, applying sandpaper to it, and then sanding boards with it. This will find all the high and low spots in the panels. The unfortunate part is that you may end up spending a lot of extra time and body fillers taking the waves until you get the "feel". Experience pays off here and that's why professional coachbuilders have a clear advantage.
Professional body shops also continually invest in the latest products, tools and equipment to hone their craft. This gives them another advantage when using the latest technology in tools and repair techniques. The Environmental Protection Agency restricts the use of many of the early chemicals and products, and this is another reason the cost of owning and operating paint and body shops is so high. Cheap estimates are shoddy work and there is no way to get the job done correctly without paying a reasonable price for it. Keeping an estimate low to get labor when every other shop is significantly higher means the work is either of lower quality or you will be faced with an additional estimate.
Make sure you're happy with your decision about how much to outsource versus how much to do yourself.
Components to consider
Let's start with the birdcage, the steel cage that surrounds the passenger compartment. This is where the mid-year fiberglass body panels are attached. Coupe and convertible birdcage integrates the windshield frame into the assembly. Coupe bird cages are more rigid than convertible cages because the roof structure connects the windshield frame to the rear section. Large fiberglass body panels wrap the exterior to avoid as much visible seams as possible. The roof (coupés), upper rear panel (convertible), and front panel make up the bulk of the body.
During the preliminary inspection, I found a distorted body line, so I immediately removed the paint to identify the problem. After the paint was removed, I discovered previous major accident repairs. By this Midyear, amateur body repair or Bondo body filler repair techniques were destined to reemerge. Fiberglass should have been used to fill the splice and reconstruct the sharp line.
Fenders and upper surrounds are bonded together with adhesive strips to reinforce the bodywork and seam. Fender breakpoints start approximately 1" below the top bezel and follow the crown.
Doors have steel frames with fiberglass skins. Working with the fiberglass bonded Corvette panels is very different than repairing metal panels. Mudguards are not unscrewed for replacement, which is something many DIY enthusiasts are familiar with.
Inspection
You need a good idea of what repairs have been made over the years and that is why all the paint has been removed. A close inspection will give you a good clue. Create a plan of attack and stick to it. Once you know which body structural parts need repairing, you can proceed with the restoration.
After finding the splice in the middle, I knew there had to be another seam. I rubbed my hand across the rear deck area to find it. This was not a factory seam, and it became very apparent as the repair shrank.
This all-metal body filler is a dripping mess that comes out of the rear inner fender reinforcement panel. I found all-metal spatula as an adhesive on any panels that had been replaced or repaired on the back end. A technician could grab this backing plate and easily pull it off without damaging it. The top left corner shows the gap between the top frame and the tub.
bottom
After the chassis was pulled out from under the 1963, I lifted the body onto the lift to thoroughly inspect the underside. I found a hidden, unknown fiberglass patchwork on the rear of the car. Turns out someone had spliced a rear section of another car to the top roof panel years ago. The center repair seam was over a frame cross member and would have been difficult to locate with the chassis in place. Of course, this applies up to the start of the paint removal phase.
I also exposed this splice seam on the passenger side that goes down into the side fender. Butt splices like these require special repair procedures or they will follow you until the repair is done correctly. Road vibrations cause cracks along the splice seam. The edges of the butted fiberglass panels become visible when spatula shrinkage occurs. In all cases, the filler in the space between the fiberglass edges shrinks, causing a noticeable line. Fiberglass needs to bridge the splice seams to avoid noticeable lines as the spatula shrinks. This area requires major fiberglass work.
Inspection of the underside revealed another problem area: the passenger compartment tub had become detached from the upper skirt. I hadn't noticed the tub joint issue on the interior so removing the bodywork was the right choice as it was very obvious with the bodywork raised. This is important because road noise would be heard and air would flow freely through the passenger compartment.
This 1965 Nassau Blue coupé with original paint shows seam distortions. The adhesive has shrunk on the left rear upper border and on the side fender. You could say it's a badge of honor when the original stitching is visible because it means this Corvette has stood the test of time. After over 44 years, all original, untouched seams between fender and upper trim should look like this.
I also found what appeared to be an all-metal body filler that was used to glue the body panels together. With this type of problem, you need someone with experience to help you make the right decisions. Is all-metal spatula sufficient for sheet metal bonding? All-metal body filler is designed to reinforce the commonly used plastic filler and prevent water ingress. I'm concerned about the adhesive strength of the all-metal spatula. Does it work as well as the prescribed adhesives for gluing fiberglass panels?
Although I've been in this business for years, I had never seen anything like it. I consulted with Al Sowash, who ran the body shop at Eckler's Corvette Service Center in the '90s. Al inspected the Midyear to find the best solution to this problem. This midyear had several pundits debating his fate. My next call was to Seth at Lucky's Customs to let him know that Al would be coming over to look at the project in the coming weeks. After a thorough inspection, it was discovered that someone had indeed used all-metal spatulas. To be safe, all of the suspect filler was ground out and replaced with fresh joint glue. You're probably wondering now why they keep talking about this glue and spatula used over and over again?
This filler issue is important because fillers shrink over time. In addition, fiberglass bodies exhibit the effects of filler shrinkage more than metal bodies. If a fiberglass seam or hole repair is incorrectly repaired, it will eventually show up and be identified by color. Even when done correctly, there is a chance that the seam or hole will become visible over time.
Perhaps you've noticed minor imperfections while looking at really nice Corvettes at auto shows. Then you may have wondered, "Why is there a dip here and there or a sunken line running along the fender where the upper surround meets the side fender?" questionable repairs will certainly bring out the worst.
You don't want to flatten a body and eventually have it show every repair that's been made. Cracks occur when a fender or inner support panel comes loose due to poor adhesion. Best possible techniques must be used to minimize shrinkage and fix loose panels. General Motors and AO Smith provided bodies that used special adhesive, but not "Bondo", to attach the panels to the birdcage.
The story is that asbestos reinforced resin adhesive was used in the early years of Corvette panel assembly. No one can prove when this deadly mixture was used, or if it was used with certainty. Multiple sources have said that Midyears were assembled using this hot glue. Also, no one seems to know for sure if all 1963 through 1967 Corvettes were made this way.
The use of asbestos is also not absolutely proven, but it makes sense to be very careful when grinding or sanding. Wear respirator and properly contain and dispose of materials.
GrindNext,
I need to find out how many other repaired spots are lurking under the old paint on my '63. I cannot stress enough the importance of removing all paint down to the bare fiberglass as the best surface for primer and paint adhesion is bare fiberglass.
I once had a Corvette painted for a client and the body shop insisted they had the perfect primer sealer that allowed them to keep the old underlying paint in place with minimal sanding. I challenged them to reconsider the job and quote it with complete removal of the paint.
After it was painted and before I assembled the exterior parts, door handles etc the paint came off. To make matters worse, it took nearly 40 hours to remove the new "dumb putty" paint. In some areas (not nearly enough) where the urethane and underlying paint were compatible, it came off easily with a razor blade. Consider yourself warned; do not make a similar mistake.
You can use abrasives or chemicals to remove the paint. First, you don't want to cut into the fiberglass panels. But some don't chemically remove paint, fearing chemicals will penetrate the fiberglass and prevent proper paint adhesion. Done properly according to the instructions, chemical stripping gives good results. When it comes to media blasting, plastic beads or baking soda are most popular for fiberglass bodies. The plastic beading process removes most of the paint without damaging the fiberglass, but I had to do quite a bit of sanding to remove all of the remaining paint. The blaster said they could remove all of the paint, but they hesitated because fiberglass damage could result. Soda blasting is less abrasive to the fiberglass, but sanding is required to remove all of the paint.
Stahl
Many people don't realize the importance of the steel bird cage that supports all the fiberglass panels. Water ingress is inevitable and will slowly rot the bird cage. If the bird cage is hidden under fiberglass panels, extensive metal damage can occur unknowingly. Rotten birdcages cause body sag and eventually cracks. A definite clue would be corroded gutters that channel water away from the doorsteps. The deteriorating gutters allow more water to enter the birdcage and damage the metal components beneath the gutters. If you find severely corroded rain gutters, consider removing the door sill fiberglass trim to verify the extent of the damage. Removing the fiberglass panel is shown in the front end maintenance section on page 52.
Our project was typical with a badly rotted gutter with some minor underlying birdcage damage due to water inrush. Reproduction gutters are available to avoid the need to fabricate an elaborate metal object. The majority of the underlying birdcage steel parts are unavailable and require custom fabrication. Luckily, the birdcage parts are relatively easy to make. Next we move onto the windshield area for an additional inspection of the metal structure.
windshield
My next concern is removing the windshield to check its frame. The Midyears used old school windshield sealing techniques which made them prone to leaks. The use of metal windshield trim clips on the metal frame allowed corrosion to begin almost immediately. When installing the stainless steel trim, they often scratched the painted metal surfaces, causing corrosion to form. As the corrosion worsened, perforations allowed water to penetrate the windshield frame and pillars, causing unseen damage. My project had some damage, but not much compared to corrosion damage I've seen on other midyears.
Chances are that even the finest Midyears that need a restoration will have rust/corrosion on the windshield frame and perforations to repair. Entire parts of the windshield frame may need to be replaced, or you may be lucky and only need a metal patch here and there.
Removing the bubbling paint on this Corvette is no problem. I was able to remove most of the paint with this razor blade scraper. While it was nice, the paint came off so easily that I need to be sure the new paint will stick. All suspect primer is removed and carefully sanded down to the raw fiberglass.
Use a long sanding block with 80 grit sandpaper to remove the paint. The splice adhesive warped the side fender at the vertical center spot where the paint was removed. This happens at every visible adhesive point on the body.
The birdcage and C-channels are in remarkable condition considering the frame was almost cut in two from corrosion. There is a corroded rain gutter behind the driver's door frame. The gutter sits on top of the birdcage where the rust will eventually find its way inside. Finding corrosion in the birdcage is common, so I was lucky that was all I found.
This is the typical windshield frame seen in the South; rusty and corroded with perforations or holes. The entire perimeter of the frame is corroded with other holes requiring minor work. Instead of welding in the small patches, I used Vette record glue and ground fiber to fill in the small holes.
Evercoat Vette Panel Adhesive/Filler is used as a top coat after applying the matting and resin. The panel adhesive prevents the fiberglass strands from protruding through the finished body.
Here are Pro fiberglass resin, 1.5 mil fiberglass mat and the hardener dispenser. The hardener dispenser squeezes the required amount into the top cup to ensure consistent measurements. If it is past its expiration date, discard it.
I have seen many southern cars with badly rusted windshield frames and no chassis rust at all. The '63's chassis was easy to fall apart due to corrosion, but the birdcage and windshield frame were in very good condition.
Don't expect all northern midyears to have the same rust/corrosion concerns. Many have much more extensive rust damage that requires much larger repair work and is difficult to complete the job.
Personally, I'd much rather change the landing gear than delve deep into the birdcage or windshield frame. A complete replacement of the windshield frame or section requires extensive work and the removal of fiberglass panels. Planning for this saves time and money. If the windshield frame is badly corroded, you should work on it with the front end removed from the body.
fiberglass repair
Never use resin that is past its sell by date as older resin tends to gel and does not flow as well as fresh resin. The air bubbles can also be worked out more easily during application. You must mix the hardener with the resin accurately or you may run out of hardener. When the fiberglass resin and hardener mix, a chemical reaction takes place that generates heat—a lot of heat. You want the finished fiberglass to be sandable within two hours. Sooner and more likely you will not be able to lay down the fiberglass mat and completely remove the air bubbles. Longer setup times can result in weak fiberglass that never fully cures. It is best to consult a body and paint supplier to purchase fresh, high-quality materials.
Fiberglass Coatings ground fibers are used to reinforce fiberglass repairs. Before application, the ground fibers (fiberglass balls) are added to the Evercoat Vette Panel Adhesive/Spatula. There is no prescribed amount to add, just add enough to slightly thicken the filler.
Consistency is essential when mixing the prescribed proportions of hardener to resin. Follow the manufacturer's recommended mix ratio, application temperature range, and cure time. Another concern is careful preparation. Strong, reliable fiberglass panels require the use of 36 grit sandpaper to roughen the bonded surfaces. You need to have your materials ready to mix, mats to install, and tools ready. Don't forget to wear gloves and have some cleaning solvents nearby.
With materials nearby, you're ready to tackle seam repairs. The goal is to connect two separate fiberglass panels and make them one piece. The repair procedure outlined here should be used wherever two pieces of fiberglass are spliced together. If done properly, the repair will remain undetectable for the duration of the Midyear's lifetime. Time is of the essence and you will need to apply a few coats of fiberglass mat before the fiberglass resin begins. Fiberglass resin takes about 15 to 20 minutes to thicken. Once the resin is activated, it's hardened and you can't make any changes. You need to sand out any suspicious areas and start over.
Next up is a really tough fiberglass repair to tackle under the left rear fender. Working on horizontal and vertical surfaces outdoors is a good place to learn. Repairing larger broken structural glass fibers can be difficult due to limited accessibility. In this particular case, I have a complete breakout on the left rear inner fender. Nobody sees the work that is being put into the area, but it is structurally very important. I could spend the better part of an afternoon properly fixing this section of broken fiberglass. Support mold plates (which take a long time to make) are required to form the missing fiberglass sections. The previous repair was done quickly with some pieces of fiberglass quickly taped to the area and then covered with primer to hide the mess. An area such as the left rear body mount needs to be repaired with integrity considerations. The same basic procedures are used to shape and reinforce the area. This is my next area that I will attack and conquer.
Previously I exposed some corrosion damage in the driver's door latch area in the jamb. I removed the door jamb fiberglass panel in the latch area to see how extensive the corrosion was. Luckily the damage was minor and only required a small piece of steel. These parts are not available and must be crafted. If you don't feel comfortable trying metal fabrication, visit a street rod or restoration workshop. Make sure you bring all the possible pieces and understand how they fit together. The shop can then make a piece to match what you need for your sample. This is the only area that needs welding, so you shouldn't have to go out and buy a welder. The next few photos will show you how I handled the birdcage repair.
Replacement of the fiberglass panel
Fiberglass replacement panels come in two forms: compression molded and hand laid. Compression molding requires an inner and an outer mold. The inner and outer molds are pressed together under high pressure, resulting in smooth surfaces on both sides of the fiberglass panel. The compression molding process is extremely time consuming, which in turn increases costs. Hand-laid panels are pretty self-explanatory: fiberglass mat is placed in the mold, then fiberglass resin is applied. Of course you can smooth the inside of a hand-laid board to look like the pressed parts, but that takes quite a long time. NCRS corvettes must have molded panels; However, hand-laid panels with adhesive strips attached are suitable for fun driver cars.
Sermersheim's (Lee Bumb Composites, Inc.) sells compression molded front end parts in a variety of ways for a proper look inside and out. You can buy the parts to assemble or buy them locally as a ready-to-install assembly with all the correct adhesive strips. Sermersheim assembles the front end ready for installation on a precise jig with the right adhesive strips and inner fenders. Another alternative is to use one-piece pressed front ends from Sermersheim and mount the adhesive strips. Seth mentioned that he likes to use the complete Sermersheimer front end assembly without the side fenders. This makes it easier for him to mount the fenders on the doors.
This aftermarket hood from Eckler demonstrates the dramatic difference between hand-laid and press-molded fiberglass. The rough, hand-laid fiberglass is easy to spot. GM did not use hand-laid fiberglass on production Corvettes. All OEM parts or panels were smooth compression molded fiberglass. To reduce costs, some body shops flatten the inner panels themselves. This is a lot of work and tricky if you plan on giving the finished panel a high gloss finish.
Sermersheim's (Lee Bumb Composites, Inc.) sells compression molded front end parts in a variety of ways for a proper look inside and out. You can buy the parts to assemble or buy them locally as a ready-to-install assembly with all the correct adhesive strips. Sermersheim assembles the front end ready for installation on a precise jig with the right adhesive strips and inner fenders. Another alternative is to use one-piece pressed front ends from Sermersheim and mount the adhesive strips. Seth mentioned that he likes to use the complete Sermersheimer front end assembly without the side fenders. This makes it easier for him to mount the fenders on the doors.
This worst-case scenario can be fixed, but at what cost? Repairs are difficult when both the hinge area and hood pillar bracket have broken away. The inner fenders are not that expensive and they look very nice compared to the current junk.
The one-piece front end is on the ground, ready to receive the inner fenders and adhesive strips. The adhesive strips are glued and then the inner fenders are mounted. All parts are then mounted with adhesive like all other body parts.
My '63 requires large front end panels or possibly a one piece front end assembly. The front end of the 1963-1967 Corvette consists of three parts: an upper surround and the two side fenders. Adhesive strips were used to attach all three pieces together. To ease assembly, a one-piece, hand-laid mold was developed for the front end. Adhesive strips should be installed to reinforce the one-piece front-end assembly. I have already mentioned that the joint seam between the side fender and the upper surround will warp over time. An advantage of using the one-piece front piece is that there are no seams to worry about later. Another benefit is that the one-piece front end takes less time to install.
In my case, I use a hand-laid, one-piece front end to save money and time. Handlaid fiberglass has distinct fiberglass strands cut on the interior surfaces. I will mount the correct adhesive strips to prevent the wheel lip from tearing. At first glance, the front section looks correct even with the hand-laid fiberglass strands. The adhesive strips are really there for reinforcement and should be used on any front end you decide to install. If your front end is fine but the wheel lip is damaged, consider replacing or repairing the adhesive strips in critical areas. Look closely at the hood hinge and hood stay area, which will be damaged in even a minor frontal impact. Repairing the inner fender in this area is possible but you may end up chasing it. Because the hood hinge and inner fender splay area are under a lot of stress, repaired cracks almost always come back with a vengeance, far exceeding the original crack location. At this point, it may sound like I can't decide. I will be using press formed inner fenders instead of hand laid pieces. The press-molded parts are easier to install and the price is close to the hand-laid parts. Both the inner and outer surfaces of the inner fenders are actually quite visible, in contrast to the unfinished interior of the front end itself.
Removal of the fiberglass panel
Removing a fiberglass panel is not for the faint of heart:
You need to loosen the connecting adhesive from the panels. Hearing the crunch of fiberglass as you undo each seam can be unnerving. To make things even more difficult, you must remove the part to be replaced without breaking the connecting flange. Professionals use a variety of specially shaped scrapers and knives to access the bonded areas. The idea is to avoid damaging the mounting flange of the fiberglass panels.
If you can heat the connecting glue, it will come off more easily. However, it makes more sense to first break or cut the damaged panel near the splice. Heat can then be applied to facilitate removal of each panel. If you're applying heat, a large, stiff scraper works well to separate the bond.
The hand-laid, one-piece front end sits upright and is ready to install. The tan vertical adhesive strip is located just above the wheel opening. The lap joint is where the front and back strips come together.
Once the parting tool has been placed between the flange and plate, slowly tap it around the part to be removed. Make sure you keep the tool centered in the splice glue. Do not dig into the fiberglass mounting flange, because it is difficult to restore the original strength when broken.
Once the entire panel to be replaced is out of the way, flange cleaning begins. The idea is to just remove the old joint glue and then rough up the flange for the new glue. Remember that the fiberglass will quickly disappear if you use a high-speed grinder.
When all the flanges are cleaned it's time to assemble the plate. Most fiberglass manufacturers leave material on each end of the plate to allow for proper alignment. They usually have notes on the panel that say "FIT BEFORE PAINTING". That absolutely means you own the panel if it has paint on it.
Since I'm installing a large fiberglass assembly, I need to consider what other body panels will be affected. I should check the door gap to the door frame before installing the front end. My resto expert Seth likes to center the doors on the hinges first. Then he checks the fit of the front door where the front edge meets the vertical door seam. The goal is to avoid major reconstruction of the front door gap. Seth explained that if needed he could build up the back of the fender for a nice, tight, even door gap.
Always consider what other panels come into play before attaching panels.
For the '63, I need to check the fit before gluing: I had a really nice looking 1966 convertible come into the shop in baskets, boxes, dollies, whatever. The body was finished and the paint looked very nice. I just had to assemble it. After being involved in so many of those "all you have to do is put it together" projects, you become very skeptical about these jobs because they are never that easy.
The first tool I pulled out of the box was a tape measure. With the customer standing next to me, I measured the frame diagonally. Sure enough, it's been optimized. The first thing to do was set up the frame. But that was only the first of one problem after another.
After the frame was assembled, it was time to assemble the body. At that time I found some serious problems. Remember I said the body was really nice color. But when I started assembling the exterior, things went horribly wrong: none of the taillights fitted properly into the rear bezel. They weren't just a little off; The rear bezel required extensive reconstructive surgery to get the lights to match.
What I'm trying to emphasize here is that you make sure everything fits before spraying any primer and absolutely before applying any top coats. This project cost a lot more to fix everything to keep the car looking presentable.
The doors should be installed on the hood before hanging the front car. The front end can be held in place with screws as each section is assembled. If you feel the front has been fitted correctly, go back and check the door gap. The old adage “measure twice, cut once” applies here. Fit everything carefully and then check everything again for fit. Once you've glued the panel in place, you risk damaging it if you have to remove it for placement changes.
You should have everything ready and waiting for the glue installation process. The fasteners holding the front end in place should be removed and the front end set aside. Keep all fasteners in an easily accessible location with the correct installation tools. Now the connecting adhesive is mixed for application to the flanges.
Be sure to read and understand the adhesive manufacturer's recommendations, particularly around set-up time. You need to apply the glue and then attach the front end with the fasteners within a set time depending on the ambient temperature. Once the front end is in place, your fasteners should be installed to align the assembly correctly.
Wipe off excess splice adhesive. General Motors, of course, didn't do that; They assembled many cars every day, so assembly line workers wasted very little time cleaning up. For NCRS vehicles, the excess adhesive should not be wiped off for authenticity. At this stage it is necessary to wait for the glue to set, which often means leaving things in place overnight.
Once any major fiber optic issues are resolved, minor repairs should be made. The details have a big impact on how good the finished project looks. On a previous inspection I noticed a few extra holes in the firewall from accessories added over the years. Unscrew holes in the fiberglass strip easily and require repair to avoid having to use incorrect hardware. Review your notes from the disassembly phase and complete the repairs before the paint is in place.
Now comes the final fit check. This is your last chance to make any adjustments or changes to the fit of the components. Check the fit of each emblem in its respective position. Do they sit flat on the plate? Make sure the grille, rear taillights, etc. all fit properly. Check the door gaps and hood fit. One last time can save you a lot of trouble when assembling.
You are now at an exciting point in the restoration when it comes time to install all of the exterior trim pieces and you can see how great the finished product looks. Or it can be a game changer with a "For Sale" sign and several boxes of your pride and joy on the floor.
frame repair
I've dabbled a bit in metalwork on the body and more is needed. The chassis will require some work, either simple scrubbing and light sanding or a major reconstruction. My project had a junk frame as I explained earlier. I had a few options: I could get a new frame from a known good source, or hit the swap meet. I went with an original Impact Restorations professionally built frame to make sure I had a solid, straight frame. The swap meet option might work but can be risky. Since this is the basis of the whole project, why take a risk?
Many parts are available to repair an original frame. Replacing a frame rail at home isn't for everyone. Care must be taken when aligning and making sure the frame is square. First you need to find a perfectly flat spot to fix your frame. Next, a jig should be constructed to ensure proper installation during welding.
By then, some money and time will have been expended with possibly questionable results. The cure for a corroded or distorted frame is replacement or professional repair. Let the experts take care of this very important piece of the puzzle. Once the integrity of the frame is assured, you can take over and complete the preparation and painting.
preparation for painting
If your frame is indeed square with minimal or no corrosion, or you are starting a replacement, the next step is to prepare it for painting. A thorough cleaning is in order to avoid blowing dirt from the entire body onto the fresh paint. Preferably, a full wash is the best way to remove dust and dirt. To wash off, use a water-based solution from a body shop or paint supplier.
Your paint supplier has a special product that will get the job done without leaving any harmful residue.
Green masking tape is used to check the body line of the front end in relation to the body. You want to make sure the front end doesn't go down or up. This is the last opportunity before gluing the panel to ensure the front end is positioned correctly.
In the meantime, most of the original frames have been painted several times. But that's actually a good thing, because bare frames corrode quickly. General Motors coated the frames with a mineral spirit-based product that washed off easily. Engine oil, coolant, transmission oil, and pretty much anything that dripped onto the frame would strip the coating. This means that many frames are covered in rust if they have not been previously painted. If the chassis happens to still have the original factory paint or the engine had massive oil leaks, rust or corrosion damage will be minimal.
Before deciding on a metal preparation method, you must decide what you want your reworked components to look like when finished. Bloomington Gold or NCRS chassis components require careful cleaning to avoid altering the raw finishes of the base metals. There are many ways to remove old dirt, paint and corrosion. Professional blasters are the easiest to use. Using a mix of professional blasting and manual removal of the crusted deposits on the parts can save a few bucks.
Fat and oil removal
The first step is to chemically strip away years of grease and oil. The grease that you find under every car is a mixture of dirt and oil and therefore blasting off the oily grease won't work. Grease contaminates the blast media and contaminates the equipment and blast media.
Forcing the fat into the metal with the blaster isn't good either. Thorough cleaning with an aqueous degreaser is best. Mineral spirits work well, but must be disposed of properly.
Make sure you consider where to dispose of hazardous waste before generating it. Gasoline should never be used to clean any component or part. A spark from a scraper or wire brush can ignite and potentially destroy your project and you along with it.
sandblasting
Once the parts are degreased and dry you can proceed to the next step to restore the surface of the part. If you decide to sandblast, which grit works best? Professional sandblasters are usually in a hurry to finish, so they often use aggressive, large grit in high-powered blasters. The large sandblasting grit leaves indentations and removes fine machining marks.
If you decide to go the pro-blaster route, make sure they understand what you're expecting. Ask them to use lower air pressure and a finer grit grit. If the blaster agrees to customize its work, be prepared to pay additional labor costs. Sandblasting is hard, hot and sweaty work, especially on summer days. It cost me $650 last time I had a chassis and all the attachments were blown up. While this may seem like a lot of money cleaning parts, I would have spent 40-50 hours or more cleaning it, so it was definitely worth it. Also, keep in mind that the cost of wire brushes, sandpaper, and blasting media can be high.
bead blasting
Using a bead blast cabinet is an alternative pressure cleaning method. Pearl blast grit is much finer and prevents surface damage, but takes longer. Of course, some parts do not fit in the standard bead blasting cabinet.
Large, efficient bead blasting booths save a lot of time, but are expensive. In addition, large cabinets take up a lot of valuable space in the store. Smaller, less expensive bead blasting cabinets are typically suction blasters that are not very efficient. The suction-fed blasters can be painfully slow when removing dirt and corrosion. Small chassis parts are blasted more realistically in small hobby bead blasting cabins.
Wire brushes
Motorized wire brushing is an alternative that works fairly well. Wire brushes on a bench grinder can quickly and easily remove years of dirt. However, wire brushing with a bench grinder has disadvantages, as it is often difficult to get into narrow cracks and crevices.
Wire cup brushes spun in an electric drill are more versatile and make cleaning in tight spots easier. However, these require caution when operating as you may injure yourself. Rotating brushes lose their metal bristles at high speed and are thrown at you. Slipping while using a high-speed tool can instantly remove a large meat stain.
Another serious problem is the loss of an object in the wire brush. The object could be thrown back at you and cause personal injury. Be sure to wear eye protection and leather gloves when using high-speed cleaning equipment.
A mix of wire brushing and bead blasting can save you time and quite a bit of money. Before blasting, use the wire brush cleaning method as often as possible. Once you've removed most of the debris with the wire brush, the blasting gets into the tight spots.
avoid corrosion
After the crude oil-free parts are done with the cleaning process, a time-sensitive situation begins. Washing the parts with soapy water is required to flush out the loose particles and abrasive. Drying parts with dry, oil-free compressed air as soon as possible after washing will limit the inevitable corrosion. Touching the parts with sweaty hands also starts the corrosion process. It's important to keep oily, sweaty hands and arms away from the clean parts. The use of nitrile or latex gloves when handling parts is recommended. The reason for all cleaning and preparation is to promote good paint adhesion. The labor-intensive preparation process is necessary to ensure long-lasting color. Before applying the primer I go one step further and apply a prep solution to the raw ferrous metal surfaces.
Ospho Metal Conditioner is a rust-inhibiting coating that prepares the raw metal for painting and may take a few hours on a hot, dry day or 24 hours on a cool, damp day to fully dry. Light applications work best to avoid rough spots where the inhibitor has built up.
This is the correct way to check the frame with a tape measure. If the measurements are the same, you have a square frame. What you can't check is a raised rail or a slightly curved rail. Chances are, a square frame is safe to use.
What are you doing with this frame? Unfortunately a quick coat of cheap black paint was applied over rust years ago. Many hours of manual mechanical paint and rust removal were involved. The hard part is getting the paint, rust, and junk out of any tight spots. Media blasting makes the most sense from a tax and physical perspective.
New metal or raw blasted metal turns gray as the Ospho transforms the metal surface. Those who prefer not to completely remove the rust can treat the parts at Ospho with a primer. The scaly rust particles turn black as the treatment converts them to iron oxide. Do not use this product on aluminum or pot metal parts.
dent removal
By now you may be wondering if the entire purification will ever end. Normally cleaning the chassis takes the most work and time as it is attacked not only by engine oils, transmission oil and differential grease but also by anything the road throws at it, be it water, salt or cavernous potholes. Don't forget the time it's spent on car repair jacks or worse still, jack stands.
Many, if not all, midyear frames have collapsed front crossmembers. If the cross member is not severely chipped, a repair tool is available. The tool fits into the cross member and a jig is attached to the outside to pull out the dents. A front spring must be removed to insert the tool into the frame. The best time to fix the cross member is when the frame is disassembled.
The 1963 project inspection was intended to put the requirements for body and chassis preparation in perspective. This is not the worst case body reconstruction. Oftentimes, windshield frames are badly rotted and require major trim removal to make repairs. I even saw the windshield and door pillar rot, which required complete removal of the front end. In some cases, the fiberglass roof had to be removed to access the bad parts. The better the body, the less you need to know about the structure or worry about completely rebuilding your Corvette's body.
Nahtreparatur
Step 1: Sand Fiberglass for Repair
First, a 3 inch diameter disc is used to remove most of the material in the center of the seam. You want the edges of each panel to be thin and then taper towards the top. The aggressive 36 grit disc is mounted on a flexible pad to allow the disc to follow the curvature of the slab. The paint suit and workshop vacuum help keep some of that irritating fiberglass away during this messy part of the task.
An 80 grit wheel on a larger diameter air grinder roughens the area around the seam. The taper is a bit more pronounced outwards, hopefully without grinding through the surfaces. Coarse-grain grinding wheels ensure a good bite of the resin when processing glass fiber. Be careful though as the aggressive grit discs will chew up material quickly.
Step-2: Cut fiberglass mat
You need to cut your fiberglass mat before you even think about mixing resin. There are two mat sheets that are thinner than the last top sheet to rejuvenate the repair. The fiberglass mat goes over the crown of the fender since the panel repair seam goes into the factory side fender seam.
Step-3: Apply resin and mat to the repair area
A copious coating of resin is applied over the area of the fiberglass mat. Don't try to skimp on resin here. A healthy dose of resin is required as it absorbs quickly. Make a few passes over the area, filling in the brush each time.
Step-4: Place mat on repair area
Timing is important when impregnating the first layer of fiberglass mat with resin. Apply resin to the mat until saturated. Then place it on the seam and part it down the middle.
Step 5: Fine tuning the application technique
Use an inexpensive, disposable applicator brush to press down the fiberglass mat and soak any dry areas. You want the entire surface to be wetted with resin for the next mat application.
Step-6: Squeeze out air bubbles
Between each application of fiberglass mat, use a job-specific roller to squeeze out any air bubbles. This should be done over the entire mat surface with wet resin. Squeezing out the air bubbles is very important to prevent delamination of subsequent mat layers.
Step-7: Avoid air pockets
There is an air pocket under the fiberglass mat laid over the top edge of the fender. When the mat changes direction, it tends to trap air. This can be seen as a bright circular area in the center of the vertical range. The light area is more pronounced on the left side of the splice.
Step-8: Saturate the repair area with resin
The best course of action is to saturate the vertical area with another coat of resin to remove the air pocket. An air pocket is disastrous to the integrity of the body panel, especially if it's just bottomed out enough for the grinder not to break into it. Days, months, or even years later, a large bubble can be evident when it finally detaches from the resin.
Step-9: Apply the final coat of resin and mat
The last, wide layer of resin-soaked fiberglass mat is laid down. Note that the wide fiberglass mat goes into the glass area of the rear window to avoid a ragged edge on the corner of the bodywork where the stainless steel trim sits on top. Keep in mind that this entire three-tiered procedure was completed within a 20-minute window. For best results, each coat should be applied on wet resin.
Step-10: Work in resin with roller
Start in the center and work your way outwards. Run the roller over the entire area again to squeeze out any remaining bubbles. The edges need to be rolled well so they don't curl up.
Step-11: Position the mat correctly
You need to push the fiberglass mat into the corner while applying resin to make sure it sticks well. Watch this area carefully for a few minutes. Make sure it doesn't come up and away from the window channel as it cures.
Step-12: Apply heat to the repair area
You should wait approximately two hours for the repair to set before sculpting the area. Apply heat to the entire area to confirm the integrity of the repair and ensure the repair has not been compromised. To speed up the curing process, professionals use infrared heat lamps to heat the repaired area and inspect for lamination defects. You can buy a home infrared lamp or find a deal on a pro model. An alternative to the heat lamp is to leave the Midyear outside for a week on sunny days to see if any surprises arise. Better to know before applying the top coat in any case.
Step-13: Shape rough repair area
The raw fiberglass repair is roughly sanded to bring it close to its correct contours. Repaired areas should be shaped before applying a coat of filler to keep the consistency of the filler even. In addition, when the spatula is applied, the 36-grit paper adds bite to the surface. Smooth surfaces allow the next application to peel off easily or, even worse, blister and show up later. Note the respirator. Our body builder doesn't use his painting suit to avoid the fiberglass dust. Some people can tolerate fiberglass dust and tiny splinters of glass, while others cannot. When you get these painful spots, cold water works best to rinse them off. Hot water opens the pores and pulls in the itchy fibers.
Step-14: Clean the repair area
The area is roughened up and looks almost ready for priming. Blowing away stray fiberglass residue ensures good adhesion for the next layer. Blow out all pinholes with extra care. If they are not cleaned of all deposits, tiny bubbles can appear later.
Step-15: Apply adhesive filler
Apply Evercoat Vette Panel Adhesive/Filler to seal the fiberglass strands and add strength to the area. During mixing, ground fibers are dispersed into the board's adhesive/filler to add reinforcement. The idea is to achieve the final contour with just one application. This ground fiber reinforced filler is difficult to sand and requires extra work to smooth. By applying the spatula carefully, you can save a lot of muscle power.
Step-16: Sand and shape repair area
Use 80 grit sandpaper with the block sander and make long, deliberate strokes to shape and smooth the area. Remember not to press down too hard when sanding. The repair area flexes and can cause unexplained low points. A long sanding block works best in this area to keep the surfaces flat. Don't be disappointed if multiple applications are required to get the plate contour correct.
Use a piece of round steel pipe with 80 grit sandpaper to smooth the inside contour on the rear deck. Like the sanding block, this hose keeps the sanded area spread to avoid low spots and pits.
Left fender repair
Step-1: Inspect body
This damage appeared minor until all dirt and primer was removed from the wheelhouse. Most likely, this damage was left behind by the repair work on the rear part upper fairing. The area was cleaned, sanded and prepared for fiberglass mat installation. The trick is that the fiberglass mat follows the original contour.
Step-2: Position fiberglass backing material
I secured the missing part of the wheel house and body support from inside the passenger compartment. A piece of cardboard was adapted to mimic the original fiberglass panel. Mold release wax was applied to the cardboard support mold, then a fiberglass mat and resin were applied to the area. Good to see that the large structural corner was repaired correctly and not just obscured like I found it.
Step-3: Making Replacement Body Parts
The extent of the birdcage damage is displayed in the door lock area on the driver's side. The replacement piece must be made of sheet steel. The area will be cleaned and rust inhibitor applied before the newly manufactured part is installed.
Manufacturing spare parts for the birdcage is commonplace, so even fiberglass bodied cars require some metalwork. The part is welded in place and then coated with primer to prevent the same thing. Once the fabricated metal piece has been welded in place, the Original Equipment fiberglass rocker cover can be fitted.
Panel removal
Step-1: Prepare bonding area
Use 36 grit sanding discs to remove any adhesive residue. The aggressive grinding wheels roughen the flange to create a good surface for the bond bite. All flanges should be cleaned of old adhesive before assembling the front end. Clean each panel to be replaced prior to installation.
Use a 36 grit sanding disc to roughen the edges of the fascia or panel to be bonded. This is very important for proper adhesion of the panel. When sanding is complete, blow off any remaining dust and dirt.
Step-2: Apply pressure sensitive adhesive
The adhesive is ready to mix. Be ready to apply it quickly because you have 20 minutes to spread the glue and have the panel or front end in place. Once the glue starts to set up, you won't be able to get the panel to stick.
Apply board adhesive to the flanges with a bead about 1/2 inch thick and now the process needs to continue. Apply glue to all top flanges, leaving the vertical parts for the next application as there is not enough time to apply glue to all joints at once. Don't try to do too much at once. Better to be safe or you may have to take the entire front end off and try again.
Step-3: Position fender
Now the front section with the mounted inner fenders can be put on. The side fenders must be pulled outwards to bypass the hood at the doors. You must plan the procedures before mixing the adhesive. The front end must be returned to the same position in which it was fitted as soon as possible.
Step-4: Set and tighten clamps
Place clamps approximately on each foot to ensure the adhesive is flattened at all attachment points. Be careful with the clamps and don't apply too much pressure. It needs to hold the slab firmly in place, but you don't want to crush the slab. Therefore, do not over-tighten the clamps. If you hear a click, release the clamp immediately.
Step-5: Adjust the correct distance between front end and hood flange
Insert a screwdriver between the front end and the hood flange. This leaves a sufficient opening into which the adhesive can be pressed.
Step-6: Install the screws in the fenders
Now the screws used for alignment are reinserted into the side fenders until the adhesive has dried. The adhesive should set within an hour if mixed properly. If not, the panels will easily pop off with a slight jerk. Then you have to start over to sand the flanges for a fresh start.
Step-1: Apply metal surface prep
Apply Ospho Metal Surface Prep with a sprayer and then wipe off. Try to avoid allowing the material to pool as this will cause crusting on the pieces. Unfortunately, the remaining of the crust particles makes them very noticeable after painting. Ospho contains phosphoric acid so make sure you wear gloves and eye protection and avoid getting it on your body or clothing.
Step-2: Remove dents
This nifty tool kit from Corvette Central straightens the front cross member. The top attachment tightens to push out the bumps and waves. When tightening the fastener, heat can be applied to the cross member. The cross member should be cleaned of grease or oil inside before heating. For the most part, the front cross member dent tool worked well. I applied a thin coat of all metal spatula to smooth it out completely. This is the perfect use for the extra tough all-metal spatula. I used all-metal putty on some spots on the chassis to smooth it out before priming.
Step-3: Clean up the frame
One of my favorite annoyances is all the slag and debris that's left in the factory from the welding process. I use a cold chisel to knock off the beads of weld all over the frame. No, it's not NCRS correct, but it sure looks better. Another plus is the reduced risk of personal injury if your hands accidentally touch the frame while you are working on or near it.
Written by Chris Petris and published with permission from CarTechBooks
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