If you have followed the procedures in the previous chapters, your Corvette body has been separated from its frame and mechanical components. The body has been mounted onto a dolly that allows it to be moved and transported around the shop or to another location.
This Tech Tip is From the Full Book “HOW TO RESTORE YOUR C3 CORVETTE: 1968-1982“. For a comprehensive guide on this entire subject you can visit this link:
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The interior has been completely removed (as it was in the 1980 subject car because a new interior from Corvette America was going to be installed). If reusing the interior, it is a good idea to remove as much of it as possible to avoid getting paint overspray on the interior parts. This also affords the opportunity to replace any worn or broken parts before the car is reassembled.
This is a good time to completely clean all of the removed parts including carpet, seat cushions, and all plastic trim pieces. If the plastic trim is nicked or scratched, repair it at this time. If this is the case, get the correct factory interior paint and fix the damage while the parts are out of the car. Remember to take extra care when reinstalling these easy-to-scratch parts.
This is also a good time to reinspect the exterior and the underside of the body for hidden damage. If the car shows evidence of prior crash damage, the damage might need to be repaired or a panel might have to be replaced. A strong flashlight is a great way to closely inspect these areas before setting the body onto a dolly. Light damage to panel surfaces distracts from the car’s appearance but does not cause structural damage.
Once the paint is removed and damage is found on the fiberglass laminate, it can be filled with an epoxy adhesive and sanded smooth. A damaged panel has to be removed and replaced with a replacement part from a Corvette supplier, such as Corvette America.
Once the inspection is completed, lower the Corvette body onto the body dolly so it can be moved to a suitable area to prepare it for painting. Remember to install large, steel industrial wheels that are on castors so the heavy body can easily be moved around the work area.
Don’t forget that removing paint, fixing broken panels, filling imperfections, and sanding the body is extremely messy work. Find an area that has plenty of light and a floor area that is easy to clean to help keep the dust to a minimum. A powerful shop vacuum is a great tool to clean up sanding debris on the floor and inside crevices in the body.
Windshield Frame Replacement
Chapter 2 included a diagram of a C3 Corvette’s steel birdcage structure that supports the body panels (see page 28). The upper windshield frame was constructed with five major components when it was built at the factory: two main pillar posts, the u per header, and two reinforcing corners. They were spot welde together to form the upper windshield frame.
The pillar posts and the header are constructed from hollow steel, and usually only the outside surfaces were painted. If a hole develops in the header, water flows down the frame and into the foot well kick panels on both sides of the passenger compartment. Cars that have spent years in moist climates are very prone to having large buildups of rust on the surfaces of their metal windshield frames. The way these frames were constructed makes them prone to rust. The upper frame was spot welded to the ends of the pillar posts. Then the corners were spot welded to both sections, but these overlapping joints were never sealed. Deterioration of the frame usually begins in these areas.
The windshield frame is covered with metal trim, and a large enough gap allows leaves and debris to collect in the channel under the chrome trim. This traps moisture allowing rust to form and it takes awhile for the area to dry out. The most troubling is that this moisture runs down the side of the windshield frame and collects in the lower No. 2 body mount area in wells beside the driver and passenger compartments. Unless these leaks are corrected quickly, the birdcage and frame rust badly and need to be repaired.
After removing the trim and discovering the windshield frame is rusted, you may be able to repair it. If the windshield frame is so badly rusted that it needs to be replaced, a reproduction windshield frame replacement pieces can be purchased from a Corvette aftermarket supplier.
If you decide to restore this part you have a couple of options. The first method requires a ton of patience and time. It also requires a 220-volt spot welder and a spot-weld drill. The spot welder has a center drill bit with an outer cutting tip built into it. This enables you to drill out all of the original welds. Then you use a hammer and chisel to cut the frame apart.
The second method is quicker. As an example, the 1977 Corvette in these photos had a very rusty windshield frame that could not be repaired. The owner took the car to Van Steel, where they removed the trim and confirmed that the frame had to be replaced.
An undamaged steel windshield frame was located at a swap meet at a local Corvette show. The VIN was carefully removed from the rusted birdcage and set aside until the repair was finished. Measurements were carefully recorded so the new frame could fit perfectly. Technicians used a reciprocating saw to cut the old frame out of the car. The seams were ground smooth and repainted in black to keep them from rusting. After about three hours of labor, the replacement frame was welded in place. The original VIN number was installed, and the repair looked good as new.
Windshield Frame Replacement
Step-1: Windshield Frame Assessment
This 1977 Corvette came to Van Steel with a badly rusted windshield frame. The frame needed to be replaced before any body repairs or painting. A stock windshield has been set in place to verify that the frame is not bent.
Rust caused severe damage to this Corvette’s steel birdcage windshield frame. This damage is not visible when the windshield and the trim are installed. This is a fairly common problem with Corvettes that have spent most of their lives in humid parts of the country.
Step-2: Measure Windshield Frame
It is very important to take accurate measurements of the windshield frame prior to removal. The best way to measure a convertible frame is from the rear bulkhead to the top of the frame. On coupes, measure from the rear roof to the windshield frame. Also measure from the floor to the top of the windshield frame on both coupes and convertibles. These measurements must be duplicated when the damaged frame is replaced.
This is an easy way to remember the driver- and passenger-side windshield frame measurements (providing your fenders are still attached). It provides a handy guide during reassembly of this critical component.
Step-3: Inspect Replacement Windshield Frame
This used windshield frame was found at a Corvette swap meet and was in excellent condition. It even had the VIN plate attached. However, it will be removed and discarded. The VIN plate from the original, rusted frame will be removed and reattached to this frame.
Step-4: Cut Out Old Windshield Frame
Use a reciprocating saw to cut through the windshield frame on either side of the T-bar on coupes. The T-bar support needs to be chiseled off once the remainder of the frame is removed. This is not necessary on convertibles.
Measure the length of the new windshield frame before you cut out the old unit. This replacement frame extends below the original lower weld joint. The original windshield frame was removed at the lower joint. The new frame needs to be cut at the same location. It is welded onto the lower joint here. Take extra care when making this cut so it lines up correctly with the lower weld joint.
Step-4: Cut Out Old Windshield Frame (continued)
The front of the T-bar is spot welded to the upper windshield frame. The windshield glass sits in a trough, and the T-bar is spot welded to the frame in the center. Cut the windshield frame near the edge of the trough to gain access to the welds. Once the welds are exposed, use a grinder to grind through the welds so the old frame can be pried off the T-bar.
Step-5: Straighten T-Bar
Once the old frame is removed, straighten and smooth the bent T-bar metal before the new frame is attached to it. This is very lightweight stamped metal. It is very easy to straighten by gently tapping two hammers together.
Step-6: Remove T-Bar Attachment
Before the new frame can be installed into the car, remove the T-bar attachment from the replacement windshield frame. Cut it off with a reciprocating saw at the end of the T-bar. Use an air-driven grinding wheel to cut the welds on the T-bar side to remove the remaining pieces of T-bar metal that is secured to the new frame. All remnants of the frame must be ground away in order to fit the old and new parts together successfully.
Step-7: Install New T-Bar
The T-bar has been successfully removed from the new windshield frame and is now being fitted to the existing T-bar that was left in the car. The new frame is secured to the two lower frames that were left intact when the old frame was removed. The original T-bar is put in place as shown in the photo. Once it is lined up correctly it is clamped in place.
Step-8: Confirm Fit
With the new frame resting correctly on the two lower windshield frames, compare the height and rake measurements to the ones written down before the original frame was removed. The new frame sits on top of the two lower frame sections; they do not overlap. They need to be completely welded on all sides to secure the replacement frame to the car. Make any adjustments
Step-9: Weld Frame into Place
Tack weld the lower part of the frame on both sides of the car in order to recheck the fit. Place a tack weld on the inside and outside of each frame to hold it place. Once everything is confirmed, run a bead of weld completely around the lower frame on each side of the car.
Step-10: Inspect Final Fit
Here, the welds have been completed, ground down, and painted. The windshield has been laid in place, and the roof panels have been attached to confirm that everything fits correctly. This job took about three hours to complete.
C3 Corvette owners are very fortunate because numerous aftermarket suppliers offer both types (FRP and SMC) of high-quality duplicate replacement body panels. They include fenders, door panels, hoods, and front and rear body clips. Common damage areas usually found in the front and rear of the car include the front nose, fenders, and under the front valance panel. In the rear the bumper and tailight areas are also common places to find damage.
Many of these areas can be repaired instead of replacing them prior to painting. Epoxy filler can be used to quickly repair small nicks or gouges on the body that have not gone through the fiberglass.
Fiberglass resin, hardener, 1/2- pint mixing container, wooden mixing stick, fiberglass sheet, metal roller, food wrap, and tape are some of the basic fiberglass repair tools and materials. This combination of products can repair cracked bonding seams and small cracks or gouges that sometimes occur in the body from road use.
The resin comes in a large container, and the MEK hardener is packaged in a small bottle. Use a disposable marked plastic cup to mix the resin and hardener together with a disposable paint stick. You can also use throwaway paintbrushes to mix and apply the resin to the body. Use rubber gloves during this procedure. The recommended mixture is two drops of hardener for every one ounce of resin. This material gets hard quickly so it best to work with small amounts at a time. The fiberglass sheets are laid onto the damaged area and the resin is applied to the sheet and rolled onto the body. Once it gets hard it can be ground down, finished, and painted.
Several disposable work gloves are also handy to have when working with these materials. The resin sets up quickly and is difficult to remove from your hands.
Structural Damage or Broken Parts
Doing these repairs yourself before the car goes to the paint shop (as long as the paint shop agrees beforehand) saves a lot of money.
A panel that’s suffered from a serious collision can completely split or rip. You need to repair this damage because road vibration causes such a crack to grow.
First, drill a small hole at the end of the crack to prevent it from spreading. Then grind the entire area out so that the crack is completely exposed. Depending on where the damage is located you may or may not be able to insert a bonding strip behind the damage. If the crack is ground out enough, you can force in enough fiberglass sheet, resin, and hardener to properly repair the damage. When the repair is completely cured, it can be easily sanded and shaped so that no repair is visible.
Body panels that are broken in two require a backing strip or patch to be placed behind the damaged area. Scrap pieces of fiberglass work well for these repairs if they have the correct contour of the area that needs to be repaired.
If the pieces don’t have the correct contour, a new patch can be created by placing a piece of polyethylene film material over the area that needs to be repaired. This film is the same type that is used to wrap food. Make it large enough to extend at least 3 to 4 inches beyond the repair area.
Cut a piece of fiberglass sheet, saturate it with resin and hardener, and place it on the film. After it hardens, remove the plastic sheet. After it cures, it can be used as a patch on the inside of the damaged panel.
With either kind of patch, use a grinder or sander to make the inside of the broken area rough, and cut the patch so that at least 2 inches overlaps the damaged area. Drill two small holes in the patch and thread wire through it to hold it in place. Cover the patch with resin/ hardener and use the wire to keep it tight against the panel. After it cures,remove the wire.
Now clean the area around the damage, place fiberglass sheeting over the area, add resin, hardener, and let it cure. Once the resin is cured, sand and feather the repaired area into the rest of the panel.
Broken parts, such as a fender, can be cut out of the car along thei factory bonding seams and replaced with aftermarket parts that duplicate the original units. Use a powe grinder to cut along the factorybonding strip, and then remove the damaged panel. Scuff and sand the front surfaces of the replacement panel and the adjacent panel about 3 to 4 inches from where it is attached.
Also scuff the bonding strip and the underside of the replacement panel, and wipe them clean with a cleaning solution. Bevel the attaching edges 30 degrees to form a V-joint. Apply an epoxy adhesive and clamp the parts into place. Fill any open spots and finish the area by grinding, sanding, filling, and priming the repaired area.
Cracked Bonding Seam
If the car has a cracked bonding seam on the front or rear, grind it out and fill it with a new resin and fiberglass section. Remove all of the paint around the cracked area before starting this repair.
Use a grinding wheel or a belt sander to form a shallow V along the crack of the bonding seam. Scuff above and below the area to provide an adequate surface for the materials to adhere. If the seam is completely cracked, adding a bonding strip on the underside for strength may be required. Fill the seam with two-part epoxy filler to bond the crack back together. After it cures grind it smooth.
Place small strips of fiberglass sheet that are impregnated with resin over the repaired seam. After the repaired area has had adequate time to cure, sand, fill, and prime the area. A heat lamp can reduce the curing time dramatically.
Fiberglass Crack Repair
Step-1: Identify Cracked Fender
Both rear fender-bonding seams on this Corvette were cracked from age and needed repairing. Before a repair can begin, grind down the seam using an angle grinder with an 80-grit, 5-inch abrasive wheel. This removes a majority of the old bonding material (shown). Next, use a 3- or 6-inch air grinder with 100-grit sanding wheel to grind the crack out. Make a groove with the sanding wheel so the repair material has a good bonding surface. Tape and paper off the area to be repaired to prevent excess resin dropping onto other parts of the panel that are not being repaired.
Step-2: Pour Resin into Mixing Cup
Pour a small amount of resin into a mixing cup. Don’t forget to add two drops of hardener for every one ounce of resin.
Step-3: Add Hardener to Resin
Add the correct amount of MEK hardener drops to the container. Use a disposable stick to quickly mix the two together before the resin sets up. Make sure the hardener and resin are thoroughly mixed so the resin correctly and effectively bonds to the fiberglass. You don’t want to redo the work.
Step-4: Soak Fiberglass Strands
Pull apart the straight edges of a fiberglass sheet to help blend the fibers into the existing panel Use the mixing stick (shown) to be sure the the fiberglass strands are thoroughly soaked with resin.
Step-5: Apply Fiberglass to Panel
This step is a very rapid process because the resin sets up quickly. Be sure you have all necessary items nearby before starting. Place some resin-saturated fiberglass onto the repaired panel (shown). The mixing stick or a paintbrush are good tools to use. Notice how the resin drips onto the taped-off area.
Step-6: Squeegee Resin into Repair Area
Use a metal squeegee to force the resin into the repaired area. The squeegee also eliminates any air bubbles that may have gotten underneath the resin. It is important to flatten the resin into the repaired area. Wait 8 to 10 hours before proceeding with the next step. If using a heat lamp to speed the set process, keep it at least 12 inches from the repair and wait one hour before moving to the next step.
Step-7: Trim Along Repair Area
Once the resin is hard, use a razor blade to carefully cut along the edges of the tape to remove it from the panel.
Step-8: Allow Time for Repair Area to Cure
The bonding seam on this Corvette rear fender has been repaired. It is usually best to wait the appropriate amount of time according to the package directions to allow the resin to harden correctly. You can speed up the process by applying a heat lamp to the area.
Step-9: Choose and Apply Filler
This Ever coat adhesive filler is especially made for SMC and FRC panels. It has enough fl ex to prevent cracking when the panels fl ex under load and provides a smooth, durable surface when paint is applied. Sand the repaired area with a sanding block and 220-grit paper to remove small imperfections that have been filled with fiberglass filler. It is very important to create a very smooth surface prior to applying primer and paint to the finished surfaces.
C3 doors are prone to striking the rear of the front fender if the hinges are weak. This chips the rear seam on the fender. To repair this area, apply fiberglass resin to the seam (left). The repair needs to be sanded and shaped for a perfect fit(right). The door should be installed to ensure the final fit is a perfect match.
Excessive Door Gap
A common area that usually needs bodywork attention is where the front fender ends at the door opening. If the door is improperly adjusted or a door hinge breaks, the front of the door can damage the seam at the door opening on the front fender. The door could break off part of the fender or crack a large area. Also, depending on how well the car was built, the fender-to-door seam gap might be excessive.
One method of repair is to break the front fender loose and move it into the correct position.
Another repair method is to use fiberglass sheet, resin, and hardener to make a new seam. This repair is easier with the door removed, but take careful measurements before taking the door off. Make sure you have a correct fit when you reinstall the door on its hinges.
Damaged Body Panel
Corvette fiberglass body panels are extremely strong, but flexible. They can take high impacts and not break; however, if they are hit hard enough they separate. Aftermarket body panels are available to complete any repairs.
A Corvette was brought into Van Steel’s shop with severe damage to its right rear fender. A large part of the lower fender was missing, and it broke along the bonding seam. The old fender had to be ground away from the car’s upper rear deckbonding seam. The remaining fender was ground away, and all of the adhesive on the bonding strip was removed.
A new lower rear fender was ordered and upon its arrival the fender was prepared for attachment. The inside of the new fender was roughed up with a rotary sanding wheel to help the adhesive bond to the fender.
Van Steel used clamps rather than screws, which is a more common method to secure the new fender while the bonding epoxy cures. Once the fender cured, the bonding seam was sanded and any small imperfections filled and prepared for painting.
In 1973, Corvette introduced a soft front bumper cover (made of injection-molded urethane) to comply with the federal 5-mph-crash bumper and it covers the standard metal beam attached to the frame. The semisoft cover conforms to the body. A two-piece rear cover was added in 1974 for that year only. The rear cover became one piece in 1975 and remained that way until the end of C3 production in 1982.
Over time sun exposure created waves or cracks in the rubber surface of the cover. It is relatively common for large hunks of rubber to break off. If your car is going to be a daily driver and not a show car, replacing a cracked or worn bumper cover with a fiberglass replica is often the best choice.
Each Corvette has a little variation in the way each body panel fits. The rubber bumper cover conforms to those differences. Fiberglass covers do not, so be prepared to do some grinding and filling during the fitment of one of these replacement panels. Once they are fitted and painted they give the car a smooth, inished look that cannot be duplicated with a rubber bumper cover.
Final Sanding and Filling
The body of your Corvette is now nearing the end of the paint preparation process. Before moving the car to the paint shop, every panel on the car should be closely inspected for any small nicks or gouges. Run your hands over every surface and repair any imperfections with filler. Sand the body until you are sure it is smooth.
Once sanding is completed, use an air gun to blow all of the dust andsanding material off the surfaces of the car. Finally, use a spray bottle of water and a paper towel to hand wash the surface of the body.
Who Will Paint the Car?
Before any paint work is started, you need to decide who is going to do the work. The painting process requires patience and time to get top-quality results. Now is the time to think about how to proceed. You can choose to paint your car yourself or select a quality paint shop to perform the work.
Painting It Yourself
Paint preparation requires a lot of labor to make sure the foundation of the Corvette body is smooth and blemish free. Body preparation and sanding all body surfaces are also time consuming and require a lot of patience. Anything missed during this step will glare at you through your finished paint job, so be sure the body filler, primer, and other chemicals are properly applied. If not, you could end up repainting your car. When done right, the sanded surface has a smooth gloss. Panels are ripple and blemish free. Body and paint preparation consumes about 80 percent of the total time it takes to paint a Corvette. You can save yourself a lot of money if you have prior painting and body repair experience.
It is important to have access to an environmentally approved paint booth before starting. Paint is very expensive and toxic. Many states and cities have very strict environmental laws that stipulate what kind of facility is approved for applying paint. Guidelines for disposal of unused paint and materials vary depending on where you live. It is a good idea to get all of the details before beginning your project. The days of just hanging a sheet in your garage are over.
If you are determined to paint your car in your own garage, then you need to construct a temporary paint booth. Using one dramatically decreases contamination. It should be fitted with the correct lighting, filters, heaters, and downdraft fans to keep dust particles from settling onto the wet surface of your new paint. However, this added side project takes a fair amount of time, money, and effort.
It is difficult but not impossible to get professional-quality paint results at home. But if you have limited or no painting experience you should look for a competent paint shop to paint your car.
Selecting a Professional Shop
It is important to preselect a paint shop before beginning any paint preparation. Art Dorsett, for example, works closely with Mike Tackley of Tackley Auto Body for paintwork. here are three types of shops that perform paint work. The first is a production shop that specializes in insurance repair. They operate on a thin profit margin and the less time it takes them to complete the work the higher their profit. Be cautious in selecting one of them because they might not take the time required to give a quality finish. The price might be right but the quality probably suffers.
The second type of shop is one that does complete restorations. They usually work on a project from start to finish, rarely agreeing to allow owners to do any pre-paint work. They make their money by charging by the hour and pride themselves on giving their customers a top-quality, finished product.
The third type is an independent shop that performs a variety of body and paintwork. This usually includes crash repair and restoration work. Many turn out quality work and are sometimes willing to let you do some or all of the pre-paint preparation work.
The condition of the body after the pre-paint preparation has a big impact on final paint results. This is the reason many shops will not paint a car if they did not do the bodywork. If they are unsure of the pre-paint preparation they will probably be unwilling to provide a warranty for their part of the job. If you insist on doing this work yourself, it is critical to preselect a paint shop that is willing to let you prepare the car.
If the shop agrees to this arrangement, it is important to communicate regularly, tell them exactly what you are doing, and ask their advice as you proceed. Be sure to let them know what materials you are using and follow their advice.
Old Paint Removal
Remove all trim and emblems before starting to remove the paint. You may notice in some of the accompanying photos that all of the trim was not removed before starting. These photos were taken for demonstration purposes only.
Razor Blade Method
Using a tool with a flat razor blade is one of the oldest ways to remove the paint from a Corvette’s fiberglass body. This chemical-free process can be completed fairly quickly and is the most inexpensive way.
A good place to start is on a long, flat panel, such as a door or a flat spot on a fender. Start slowly and with light pressure. You quickly determine how much pressure is required to scrape the old paint off the panel. You may discover that your car has many coats of paint, which strip off pretty quickly.
If you slip up and turn the blade a little sideways you risk gouging the body. This requires extra bodywork to fill and sand the gouged area. So try to keep the razor blade flat on the surface at all times.
Many brands of chemical paint removers are on the market. These chemicals can remove large areas of paint very quickly, but they are very messy. It is much easier to work on small areas at a time. You can minimize the mess on the sides of the car by using tape and paper to catch the paint and solvent as it is removed. Fiberglass is very porous and absorbs the chemicals if not removed quickly. This is another reason it is better to work on a small area at one time; it is easier to clean the area before proceeding to the next location.
When done correctly, the surface does not get nicked or gouged, which can happen when the body is scraped. This method reduces the amount of paint preparation work.
These chemicals are very toxic so remember to wear a long-sleeve shirt, trousers, and gloves to avoid exposing your skin to the chemicals. In addition, always wear goggles or shop glasses.
Most professional body shops prefer the chemical removal method because of the short time it takes to remove all of the paint.
Sanding is a lot of work and takes a lot of time to complete. A 150-grit sanding disc is a good place to start but be prepared to move up to a 400- grit if the surface is being scratched. Continue adjusting the grit as you proceed removing the paint. You don’t want to use too coarse of a grit because it damages the fiberglass gel coat.
Load up your 16-inch sanding board with paper and start going at it. The time it takes depends on how much paint buildup is on the car.
Written by Walt Thurn and Posted with Permission of CarTechBooks