From Paint to Bare Metal -
From Paint to Bare Metal -The experience of paint stripping
Most of our cars have been treated to many coats of paint. When it is time finally for a repaint, the question is: Do I need to strip the car, and if so, how do I get the car's surface down to bare metal? There are many ways to get this done, including dipping, sand blasting, media blasting, chemical removers, and plain old sanding. Some of these can either be handled by someone else or as a do-it-yourself project. In a few instances, the work requires specialized equipment and must be performed by others.
In this article I will share my experiences with stripping a Camaro to bare metal.
The subject vehicle is a 1970½ Camaro. The finish on this car is typical, or maybe a little worse, than what many of us begin with. The car had a repaint about six years ago in the original color over the factory paint. The repaint was apparently done in lacquer with a clear coat over several coats of primer. The current finish is very thick. I've counted at least eight layers of primer, sealer and paint. The finish has also severely weathered, with the color coats shrinking over the primer-sealer. We really have no idea what is under here or how new paint would adhere. There are also some areas of apparent collision damage that have been repaired. In some of these spots, the paint is not adhering to the surface, where the paint and possibly body filler have lifted from the metal, allowing the body panel to corrode.
The plan is to repaint the car in the original color. I do not want to disassemble the car other than removing the doors to rebuild the hinges, removing the front clip for detailing and replacing one fender. The door jambs and the underside of the trunk lid have original paint in good condition and I want to preserve that finish if possible. In looking at the finish, the paint now on the body appears too unstable to use as a base for a repaint, thus it will have to be removed.
How to Strip the Body?
The first step was to determine how to remove the paint. I considered various methods.
Dipping: I did not plan to completely disassemble the body shell, thus did not consider dipping of the body as a viable option. The chemicals get everywhere in the body, including seams, requiring extensive cleaning and treating. Since the fenders were in good shape, without damage, rust or filler, it was decided not to have them dipped.
Sand blasting: This can be a do-it-yourself job or something done by others. In the wrong hands, sandblasting can warp and harden the sheet metal. In any case, the sand will get into many parts if the car where it will be very hard to clean out. Hiring someone else to do the job requires taking the car or parts to another location. Since I did not want to drive or transport the car, having someone else sand blast the car was not an option. Doing the work at home was also considered but rejected, since I did not feel that I had the skill, and the sandblasting would make a considerable mess at home.
Sandblasting does have the advantage of removing rust to get to clean metal. I will probably sandblast a few small localized spots of rust in the window channels. More on that as the project moves along.
Media blasting: This approach is handled by specialists with the proper facilities and equipment. The media used is plastic or another material that is less abrasive than sand. Several club members have had good results with this treatment and recommend it. Again, since I did not want to drive or transport the car, this was not an option.
Media blasting will remove paint, but will not remove rust. Cost can run from $450 to $650, depending on the car and finish to be removed.
Sanding: After cleaning a few spots to bare metal for repairs, I determined that the paint buildup was too thick to consider sanding the entire car. While some spots will need to be sanded, the time involved to sand the entire car was more than I wanted to commit.
Chemical removers: This left me with chemical stripping as the other alternative. Having stripped two cars previously by this method, it was decided that a third could be done without great difficulty. The only mess in the actual stripping is in the area immediately surrounding the car. Sanding to provide a final clean-up of the metal is required, but the work could be done with another car in the garage, and the dust problem from the sanding would not be as severe as with sanding off all the paint.
Based on all the circumstances involved, I've decided to use a chemical paint remover to strip the existing paint from the body of this vehicle. My next step will be the removal of any trim that could get in the way. That will include the trim surrounding the windshield and rear window as well as door handles, locks, bumpers, lights and anything else that could get in the way.
The first thing done was trim removal. Front and rear window trim pieces were removed, using a special tool. Weatherstripping on the doors and trunk was also taken off, with plans to replace it after the repaint. The bumpers, lights, door handles, locks, and all other trim came off. One task that not everyone would face is the removal of the rear window and cleaning the window channel
We wanted to repair was a small water leak into the trunk. With the rear window trim removed, it was determined that there was possibly a small hole on one or both sides of the window channel that needed repair. Several spots of surface rust were also found where the window trim met the body. With the trim off, we found that the seal on the rear window was starting to release from the glass in some spots. It was decided that the rear window should be removed, the problems corrected, then the window replaced.
Since the hood was being replaced and the door hinges needed to be rebuilt, the front clip came off the car as well. This allowed us to get to the inside edges of the fenders as part of our repaint and will also allow us to get plenty of paint on the inner door jambs and other hard to access areas. Having these parts off and working with them on stands made it easier and more comfortable to get to all the edges and hard to reach spots. This took more time than expected, since someone in the past apparently didn't trust bolts, so bolted and spot welded much of the front clip together. Some careful work with a cut-off wheel and hacksaw got all the pieces separated.
Surface Preparation Begins
To get ready to apply the chemical stripper, we began by applying masking tape to all seams between panels and other openings (Photo 1). This tape keeps the chemical stripper from flowing into the openings, messing up paint in the jambs and keeps the stripper from possibly going into a crack or crevice when it could later come out and damaged the finished work. Either masking tape or duct tape works for this step, with duct tape being a bit more durable. The windows and window openings were also sealed, using plastic sheeting and duct tape (Photo 2). Openings in the body, such as trim holes, lock and door handle mounting holes, taillight openings, etc., were sealed in one of two ways. If the opening was accessible from the back of the panel, tape was applied from the back to seal the opening and prevent the stripper from going behind the panel. When the back of the opening was inaccessible, the holes were sealed with a piece of tape on the surface. With this approach, care must be used when scraping off paint and stripper later, as the tape can be removed with a scraper.
One word of advice here. You will want to have enough of an edge taped to allow the tape to remain sealed if it is bumped or hit during the chemical stripping process. However, we found out that the more paint you leave covered with tape, the more you have to sand later. About ½" border around the windows appeared to work well. We used ¾" wide masking tape on the seams, although the next time we would use a narrow strip of duct tape because it may adhere better.
Work Space Preparation
Strips of sheet plastic about three feet wide were placed under each side of the car as well as the front and back. They were placed far enough under the body to catch (hopefully) all the paint and stripper combination that we used. The only other preparation was to get the car away from walls so that the work surface was well lighted. We used work lights to illuminate some dark areas at the bottom of the rear quarter panels. Good lighting allows you to see the progress of the stripper.
The first thing you will need is some paint stripper. While we have used several different types of stripper, this time we used Kleen-Strip's Aircraft Stripper (AR-243). These are both very strong and get the paint off quickly. Two to three gallons should be enough to strip most cars, at a cost of about $18 to $25 per gallon. The quantity used will depend on the size of the car and how much paint needs to be removed.
You will need an old coffee can to hold the stripper and an inexpensive wide paint brush to apply the stripper. Plan to discard both of these when you are finished. For stripper removal you will need some of the flexible blades used to apply plastic body filler. These can be used for scraping without the risk of scratching the metal, as a metal putty knife may. You will also need Scotchbrite™ pads for final clean up and 80 grit sanding disks to use with your dual action sander for sanding the metal.
As you strip off paint and primer, you might find some body filler, or maybe a lot of body filler. Body filler will be softened or ruined by the stripper and will have to be removed. If you have an area of filler that you do not want ruined, sand the paint off before stripping, then mask the area with plastic to keep stripper from affecting it.
For safety, you will need several pieces of equipment (Photo 3). Plan on using heavy rubber gloves (the type used for industrial chemicals), good goggles or safety glasses that provide wrap-around protection, and a respirator mask that will filter chemical vapors. Later you will need a dust mast when you sand.
Start with the basics: read the instructions on the can! As stated there, this stripper is not for use on rubber (Endura) or fiberglass parts as the chemicals can damage them. There are other strippers for those materials.
The stripper works as the chemicals evaporate and soften the paint. To speed penetration, you can scuff the painted surface with 40 grit sandpaper. The instructions indicate that the stripper works best in 50° to 75° temperatures. To allow the stripper to have plenty of time to work, do your work in the shade. To get more action out of the stripper before the chemicals evaporate, after brushing the stripper on, cover it with plastic to slow the evaporation. Let the plastic adhere to the stripper. We used the least expensive kitchen wrap for this and it worked fine.
Our experience was that the chemicals work at their own pace and that the quality of the removal varied between areas of the car, even on the same panel. Some paint came off on the first try, other areas needed several applications of stripper. We had something else to do during the 15 to 45 minutes that the stripper was working, so we just stopped back to check it occasionally. By letting it do its work, you will have less paint to be sanded off.
When the paint appeared to be softened, the plastic sheeting was removed and placed in a bag to go to the hazardous waste site, where the empty cans and other waste will also be going. After the plastic was removed, we scraped the surface with the plastic filler applicator. All the stripper-paint mess also went into the bag for proper disposal. Our first treatment got most paint off in some spots and little off in others (Photo 4). We then reapplied the stripper to the entire surface and recovered it with plastic. By the time the second application was ready to remove, we were getting down to the primer and bare metal. A few spots required a third application, but after that most of the paint residue was gone.
With most of the paint off, the next step was sanding the surface to remove the remaining paint. Before sanding the metal, we brushed on a very light coat of stripper and scrubbed the surface with a Scotchbrite pad. This removed most of the small chunks of paint. The surface was then wiped down with lacquer thinner to remove dried stripper and paint. Following the wipe-down, we sanded the surface with 80 grit sandpaper on the dual action (D-A) sander. The 80 grit paper was chosen because it works fairly rapidly and leaves a bit of surface texture for primer to grab. As we said earlier, by taping too large an area around the windows, we ended up doing more work, since there was more remaining untouched paint.
While the D-A sander worked well for the large flat and lightly curved surfaces, it could not get into the small contours of the body, especially on the tail panel. For that area and other detail areas, we used a 3M Rust & Paint Stripper, a plastic-fiber wheel on a spindle for use with a drill. It gets through the paint without being too abrasive to the bare metal.
Where we did find body filler, it was ground out and replaced. A wire brush on a drill worked well for this. We were finally able to assess the actual body condition for the first time and determine what work needed to be done.
Finishing this phase
To protect your work for a short time until it is covered with primer, consider using a metal preparation product, such as Metal-Prep.
Be certain to properly dispose of your waste material and used containers from the stripping process.
As promised, we did try to keep track of the time involved. We are not overly quick at this job, so think that our time is probably pretty average. Your own time to do a similar project will depend on what, if any, problems you run into and the type and thickness of the paint and fillers on the body. Of course, this process would also work quite well for a swap meet fender or hood, rather than a whole body.
Trim removal and body teardown
Remove front and rear window trim (½ hour)
Remove window trim and weather stripping (2 hours)
Removal of lights, door handles, locks, etc. (3 hours)
Removal of rear window and cleaning window channel (3 hours)
Removal of front clip (3 hours)
Two applications of chemical stripper (about 3 hours each time)
Final application, scouring and cleaning (6 hours)
Sanding to bare metal and metal treatment (24 hours)
The total time for this work was about 48 hours, done over several months. Some time could have been saved by working steadily on the project, rather than starting and stopping.
If all when well for you, you should now be looking at a bare body, ready for bodywork and paint. Chemical stripping of paint is not an easy job, but you will know what you or your body shop will be starting with under paint.
Would we do it again? It was a lot of work, but we probably would.
Supplies we used
Safety and other equipment
Respirator for chemical vapors
Industrial rubber gloves
Safety glasses (for chemicals)
Plastic sheeting for the floor and vehicle windows
Inexpensive paint brushes
Coffee can for stripper
Stripping materials and supplies
Chemical paint stripper (3+ gallons) Kleen-Strip AR-243
3M Rust & Paint Stripper wheels (2)
Scotch-Brite pads (6)
Metal Prep DX 579
80 grit sanding disks (50)
Author: MadMike Maciolek
North Georgia Classic Camaro
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