Resto-Mod Restorations: Part 6 — Metalwork
A nice thing about a Resto-Modding is the absence of a "purist" approach where body repairs must be done using lead body fillers to fix original sheet metal that's "unobtanium" (impossible to find). When you're Resto-Modding a '67 Camaro or '69 GTO, you'll find replacements for almost every piece of sheet metal in catalogs. That makes body repairs a easier and less expensive.
While that reproduction quarter panel for a Camaro coupe may seem expensive when you're saving up change to buy it, just think how much you'd spend paying a shop $50 or $75 or $100 an hour to fix up the old part. Then, imagine what it would cost to buy a NOS Packard or Duesenberg fender.
Reproduction body panels are a good deal, but some metalwork may be required to fix small rust holes in sheet metal, to weld on new rocker panels or quarter panels or to repair severe rust in structural parts such as inner body supports, door jambs and windshield or rear window channels. These are areas of a 1960s automobile that have been prone to rusting since the cars were new.
Floor Pan Repairs
Muscle cars are getting to be almost 50 years old, so there are few unrestored examples that do not need their floor panels repaired or replaced. Whether it's best to fix a hole in the existing floor or cut it completely out and install a new one depends on how big the hole is as well as your own restoration preferences. The floor pan is an important structural part of a unit-body car so huge holes ought to mean a new floor. However, if the holes aren't large enough to step through, you can probably fix the old sheet metal and save a little money.
The actual size of the hole is rarely what you see at first. It's what you wind up with after poking and cutting out rusty metal. What starts out as a small opening can become a huge crater. If you have a crater, you'll need a full-floor panel. These come single-piece (complete floor) or as right- and left-hand panels that run the full length of the floor on each side of the center transmission tunnel.
Step 1 in doing a floor panel replacement is to remove the seats, which we talked about earlier. Then, open the doors and examine the section of the floor that you want to replace. Many Camaro restorers prefer using the one-piece panel and replacing the entire floor. However, two-piece full-floor panels or even half panels are easier to install if they are big enough to replace the rusty section.
Jeff Noll replaced the driver floor and passenger rear floor in his Camaro. Since he was fixing only two sections, he needed only half-floor pan replacement panels. Don't confuse these with one half of a two-piece full-floor kit. The half-floor section is about half the size of one section (right or left) of a two-piece full-floor panel. Some folks may think of it as half of a half of a full-floor kit.
For Jeff, automotive metalwork was new. A family friend Bruce Young owns Young's Auto-body in Muskego, Wis., and gives advice to old car restorers. Every few weeks, after work, Young stopped by Jeff's garage to show him what to do, tell him if he was doing things wrong and recommend the proper next step.
Most of the time, Jeff got a task done fairly well on his first try, but Bruce Young's years of experience were a godsend. Jeff says the car would not have came out as well as it did without Young's help. In addition, Bruce's son sprayed the Camaro's final paint after Jeff did the initial preparation and bodywork.
The rusty sections of the floor in Jeff's Camaro needed to be treated to stop further rust and then repaired using traditional body work techniques.
Jeff cut out bad sections of the old floor and trimmed replacement panels to fit inside the cut out area. Then they were butt-welded in. Butt-welding eliminates overlapping sheet metal with gaps where corrosion could re-start. Jeff was able to sell leftover sections of the replacement panels on eBay to re-coup over half the cost of the new replacements he bought.
Jeff cut out the rusted-through sections of the driver's floor that couldn't be saved. He gave the other parts in the area a coat of red oxide primer to stop rust.
Jeff MIG welded the trimmed panels in place, putting tack welds at all four corners and filling in with tacks every few inches around the perimeter. Once everything was tacked, he welded different areas a few inches at a time to keep the pan from heating up and warping. When welding, he was careful to wear a welding helmet and heavy welding gloves to keep his eyes and hands safe.
Jeff installed only the portion of the reproduction panel needed to replace the rusted out metal (he sold the rest on eBay). After the panel was welded in, he finished the seams using waterproof fiberglass filler and sanded the fix smooth.
Once the welding was done, welds underneath the car were ground smooth. Jeff left a little weld on the top for extra strength. He then used a fiberglass filler called Marson Mar-glass to provide more strength. The green-colored filler is a waterproof fiberglass filler that mixes up like regular filler, using a small amount of hardener. It is also applied like filler, but has added strength due to small fiberglass strands in the material. It was used for initial coats over the welded areas and then tan-colored Marson Golden Extra was applied over the top of the repair for final shaping and forming. After the filler was applied, Jeff used Evercoat polyester glazing putty for final fills. This whitish-blue spot putty is much thinner than filler and fills sanding scratches and air holes that pop through.
On top of the floor, where carpets would cover the very solid repair that he made, Jeff did not spent time sanding the waterproof fiberglass filler.
Jeff used Marson Golden Extra filler to smooth the underside of his floor patches and make things look factory new underneath the Camaro. All work was done without a rotisserie. Jeff spent lots of time laying under the car with dust falling in his face. He doesn't recommend this to anyone, but says it worked.
Cutting out the bad sections of the old floor can be tricky, so do this carefully and try to get the best tools that make sense for you. In Jeff's case, the holes were cut with an Air Whizzer tool and an air saw that had a very small thin blade. An angle grinder fitted with a cut-off wheel can also be used. Another option is an air-powered chisel if you have a big compressor that won't leave you high and dry on air every few seconds. Ultimate is a plasma cutter. The cover of a recent Eastwood catalog shows a floor being cut open with a plasma cutter that Eastwood sells for a hobbyist-friendly price in the $640 range. If you do a lot of work on cars, this tool may be worth buying. If you're only doing the one car, perhaps you can borrow one or use the other cutting options and go slower.
Complete one-piece floor pans for early Camaros are favored by many home restorers. We have seen prices on these ranging from $250 to $400, which sounds extremely reasonable. Dynacorn Industries makes one version that has a good fit. Like all replacement panels, it may need minor tweaking to fit perfectly. It comes with caged nuts for attachment to the sub-frame mounting, seat belt anchors, rear seat bottom anchor hooks, and torque boxes.
We have seen shops insert the large floor panel from the front of the car from below. With the old flooring and torque boxes removed, carefully jack the rear of the car with the jack on the edges of the rocker panels. The jacks have to be spaced wide enough apart to allow the panel to slide between them. The car must also be supported on the rockers at the front and it should be level so that the body doesn't have a twist to it when you're positioning the panel in place.
The rear edge of the Camaro one-piece floor pan panel has to be pushed up on the rear package tray to allow its front edge to clear the footboard. Then you just carefully slide the whole one-piece floor panel forward and down into position. You may need to twist, pull and yank it to get it where you want it to be.
The front edge of the new floor panel should sit above the partial tunnel. It's a good idea to attach cross braces inside the body (especially in convertibles) to prevent twisting or flexing. Use heavy-duty jack stands that hold everything far enough off the floor to give you working room. The way to get the floor in is the right way. Once it is in position, get out your welder and complete the install.
Windshield Channel Repair
Jeff Noll's Camaro hardtop and Jim Mokwa's GTO convertible both suffered corrosion in the windshield channel area. This is the "lip" which the windshield glass sits against. In both cars, there was cancerous metal in the upper corners of the channel. This occurs due to water seeping behind the 40-50 year old bead of dried-up gap sealer and laying in that area for a long time. Adding to the problem is that late-1960s automobile production processes did not ensure that the metal lip was always well protected by primer or paint. In addition, the factory finishes used back then were not up to lasting a half century. This created a situation where moisture tended to collect where there was bare metal or where finishes wore off. This made the channels very rust prone.
The same was true for the rear window channel on closed cars and Jeff's Camaro hardtop had both windshield and rear window channel corrosion. In both cases, the problem and cure were the same, so we'll detail how Jeff took care of the rust up front and assume that the rear window rust repair was very similar.
After removing the glass, Jeff cut out the corroded spots using his Air Wizzer cutting tool. As in the floor panel replacement, he took out all the bad metal until hitting solid stuff. Then, he used pieces of 90-degree angle sheet metal to cover the areas where the cancer had been cut out. He cut notches in the angled strip so that it could be formed to match the contour of the windshield.
Jeff used an Air Whizzer tool to cut out the badly rusted sections of sheet metal in the window glass channel.
Small pieces of sheet metal were bent at a right angle and tacked to the windshield channel and then welded solidly together to look like this.
Once each piece was tack welded into position, the perimeter and the notches were all welded up using a MIG welder. Then any excess weld was removed from the repair by using the Air Whizzer and a die grinder. Jeff tried to keep the repaired area from extending into the roof panel. This way, most of the windshield channel that repairs had been made to would be covered by the bright metal windshield surround trim when the repair was completed.
Jeff Noll ground down the weld until it was smooth and sealed it with waterproof fiberglass filler, which he then sanded smooth like this.
After tack welding the angled metal patches in place, Jeff again used his Marson Mar-glass waterproof fiberglass filler to add strength and water resistance to his repair. He then applied his Marson Golden Extra so that the corners of the windshield could be shaped properly. Jeff avoided using lots of filler where the windshield sits to get a nice metal surface to bond the new windshield to.
After all of the bad sections of the windshield channel were repaired with metal tabs, welding and body filler, Jeff covered the repairs with green primer.
Rear Quarter Panel Repairs
Jeff followed the advice of Bruce Young in using full rear quarter panels on his Camaro. Young told him that it is actually more work to weld in smaller partial panels that run along the body line. With the smaller sections there is also a higher likelihood of future rust and potentially more bodywork issues. Jeff had already gotten smaller half-size quarter panels when he bought with the car, so he used these to repair the inner rear wheel wells, which were also rusted out.
The entire lip was cut out of each of the smaller quarter panels and the lips were used to repair the inner wheel wells. Jeff put the remaining pieces of each of the smaller quarter panels on eBay and they were snapped up by other Camaro restorers. This allowed him to offset a portion of the cost of a set of new full quarter panels that he purchased from a reproduction parts supplier.
In the blasting chapter we showed the rust that appeared when the trunk metal was blasted clean. Jeff had to weld reproduction inner wheel tubs and all new quarter panels onto both sides of the Camaro body.
This is a view of the original undercoated tub for the car's right rear inner wheel housing. As usual, undercoating served to hide rust that formed under it.
Replacing the quarter panels was probably the biggest challenge of the entire restoration, due to the amount of cutting and fitting and alignment that was necessary in this work. Jeff saved the car's original factory trunk lip. Though it seems amazing that the entire rear of the body could be reconstructed working off this thin lip, preserving it proved to be a key factor in making sure that the new quarter panels could be properly aligned on the car. The other key factor was replacing just one side at a time to avoid losing the alignment of the trunk lip.
After removing all of the bad metal at the rear, only the original trunk lip was left. Jeff reconstructed the entire rear sheet metal assembly using the old trunk lip for proper alignment of the rear quarters and other body panels.
This is how the rear end of the '67 Camaro came out after Jeff added full new reproduction rear quarter panels to each side. These panels formed the fenders, left and right side trunk surrounds and portions of the roof.
Major quarter panel repair began by cutting out the old quarter panels with the Air Whizzer tool. Cuts were made along the inside of all connection points so that only an inch or two of material was left at all those spots. A spotweld remover drill bit was used to remove all spot-welds and an air chisel was used to remove the final inch or two of metal. All of the factory-applied lead filler had to me melted out of the overlap used where the rear quarter panels met the roof line. Jeff used a torch and wire brush to remove the old lead filler and get the metal in the rear quarter panel to roof mating areas as clean as possible.
Once the area was cleaned of lead, Jeff went over it with a wire wheel. This made the spot-welds obvious, so that they could then be removed. All attachment areas where cleaned up with a wire wheel and Air Whizzer. They were then covered with "weld-through primer" to prevent future rusting.
The replacement rear quarter panels had to be trimmed to fit. About 20 test fits and re-trims were done to each side to ensure of a proper fit before the rear quarter panels were welded in place. The panels also had to dovetail with the rear window base panel that runs across the top of the trunk. Then all these parts had to be checked for proper alignment before final welding.
Holes were drilled in the edges of the replacement rear quarter panels so that Jeff could MIG weld through the holes onto the original metal and keep making small circles inside each hole until it filled and overlapped the new metal. The use of this technique created a type of weld that looked similar to the original factory spot-welds, once the welding material was ground down.
Though he used butt welds extensively in his project, Jeff took a different approach at the top of the rear quarter panels. This area came from the factory with a lower flanged edge that allowed filler to be used after it was welded. Jeff continuously welded the top of the rear quarter panels for added strength.
After a lot of work getting everything in proper alignment, Jeff welded the new rear quarters and original roof together.
As on the other parts of the car, the roof weld seam was covered with waterproof fiberglass filler that has a greenish texture and rough finish when first applied. You must use waterproof filler so the repair doesn't start rusting again.
The final step (on the other side of the car in this case) is sanding and smoothening the filler, which leaves it with a grayish color and smooth surface.
Jeff also welded behind the drip rails and, with minimal bodywork, removed the excess welding material. This gave an appearance that looked just like the original factory edges. Many restored cars have gobs of silicone or body filler inside the drip rail where the quarter panels were replaced. Jeff welded this area, ground down the excess welds and filled in with fiberglass filler. He then sanded, added Marson Golden Extra shaped to the original quarter panel profile, and sanded and sanded and sanded to get the area looking perfect.
Jeff also did some metalwork on the doors of his car. However, before any such work was done, the door hinge pins were replaced so that the door swing was tight. The doors were also taken off and put back on at least 15-20 times to get the gaps right. Final hinge adjustments were made for proper alignment.
Once everything was aligned, Jeff drilled 1/8-inch holes through the door hinges so that a drill bit could be used to realign the hinges and door any time the doors were taken off the car. This was also done with hood and trunk lid hinges so that any panel could be removed and reinstalled in the exact same position.
One of the Camaro's doors had previously been damaged in an accident and someone had repaired it using the age-old method of drilling holes in the panel and using a hook on the end of a slide hammer to pull on the sheet metal at each hole. Then, the holes were closed up with a MIG welder.
The driver door had once been damaged in an accident and someone had repaired it by drilling holes in the panel and using a hook on the end of a slide hammer to pull on the sheet metal at each hole, then welding the holes.
When the door was stripped of primer and paint, the old repair was obvious. Fortunately, the dent was not a bad one. Jeff was able to borrow a spot-weld dent puller from Bruce Young and he used this tool to rework the repair and get the dented metal back as close as possible to its original shape. Bruce's tool spot-welded small-diameter pins onto the metal so that a dent puller could be attached to the pins with a drill chuck type connector.
Once the connector is tightened over a pin, you can use the slide hammer part of the tool to tug the door panel into its original position. The trick is to work around the outside of the dent towards the center. Once the dent is completely pulled out, you simply use a grinder to grind the pin off or—with most pins—you can work them back and forth and break them off, so that they can be reused.
Jeff's doors did not mate well with the replacement quarter panels so the door "margins" had to be reworked. He was either welded material on the edge of each door or ground off some of the edge to match the door to the profile of the rear quarter panel. This required re-welding the ground down edge with a MIG welder. This resulted in very durable door edges that matched the gaps correctly without using body filler. Body filler would have to be formed into the quarter panel to match the door and would likely chip off as the doors were shut.
The door's outer skin was easy to repair, but the inner corners were rusty and also needed to be reworked (metal added or removed) to make all the panels fit right. Some body shop professionals call this working the door margins.
Once again, small metal repair patches were tack welded in place, then bead welded together and finished with grinding and waterproof filler that was shaped to aid proper fit for good alignments and sealing.