Special Report Questions For Larry
Readers Ask This Restoration Pro About Color Sanding, Brazing, Respirators, Patching Holes, Panel Sources & More.
I Want to Restore Cars to Retro Standards
After three decades of investing time and money into perfecting my skills at restoration I need some advice to pull it all together.
I have developed a system of operations and products to repair collision and rust damage and I have decided that after studying survivor cars that I want to replicate the skill level of the factory work. Judging by what most professional restorers do today that is seriously “dumbing down” the quality. But I think of modern work as blueprinting the body like a racing engine is blueprinted.
The gist of my questioning is; what is the order of operations in painting and assembly work? I know how to take a wrecked door and make it perfect, but the assembly manuals do not indicate any finish schedules or sequences.
Did they assemble the bare parts then paint? When was the body caulk applied? Were the trunk coatings applied before or after painting? Was hardware such as latches and strikers painted or cadmium plated? Was the lacquer finish wet sanded and buffed? What is that factory black primer that is so hard to remove when sanding? When were the semi-gloss colors in the interior and on the underside applied? Where and when was the sound deadener applied?
Finally, why was there a metallic red under the undercoating on the original floor pan of my factory-painted gold car?
Ed Gonfindini Via email
Before I answer your questions let me put in my two cents’ worth on quality. Way, way back quality was high. Although they lacked the sophistication of modern day factory equipment some of the vehicles manufactured in the ’30s and ’40s had panel-to-panel gaps that would make anyone proud.
However, by the late ’50s, and especially throughout the ’60s and ’70s, quality went out the window as vehicles were thought of as “disposable.” (The Chevette comes to mind.) Detroit turned out vehicles that were sloppy, ill-fitting, and basically poorly built. Then came Datsun, Honda and a host of other vehicles that were assembled by people who cared and Detroit had to change its ways, which seems to be an ongoing battle even to this day.
To answer your questions and help you restore a vehicle back to less-than-perfect, here goes:
The first step after welding and cleaning the body was to mount the doors and deck lid then caulk all of the seams. That’s a broad statement as some caulking took place during the welding process because some areas of the body became inaccessible once all of the welding had been completed.
The next step was to apply primer by electrolysis by completely emerging the body, and all associated parts, in a vat of electrified primer. This is the same black primer you seeon replacement parts.After that, the body was quality checked for runs on the exterior. Nobody cared about runs in the engine compartment, underside or trunk area. Any runs found on the exterior were sanded smooth. Runs found elsewhere were left alone.
How the trunk area was treated depended upon the manufacturer. GM liked to use splatter paint while Ford and Chrysler preferred to paint their trunk areas. The textured paint appearance on Ford and Chrysler products was from having painted over RUBBERIZED undercoating that was applied to the inner quarter panels.
After that, the vehicle moved into the paint booth where the body received its exterior color. These vehicles were never color sanded or buffed. The reason lacquer looked so good straight out of the factory was due to the method of painting, which I can’t explain here due to space restraints, and heat. Whether lacquer or enamel, all of these finishes were baked.
Next, the interior colors were sprayed. These colors were formulated to dry to a satin finish where required or left in a high gloss where required.
That’s pretty much the sequence used to refinish these vehicles.
GM, Ford and Chrysler preferred to mount the doors and the deck lid before painting the body. That is usually evidenced by the lack of paint between the hinges and the body. Chrysler also had a tendency to mount the front fenders and hood before painting as evidenced by the painted fender and hood mounting bolts.
Something the Big Three never did was to paint the heads of their bolts then install the part. If you find the head of a bolt painted, you know that whatever part that bolt is holding in place was installed before the body was painted.
You will find a lot of cadmium-plated bolts, washers and fasteners on older Fords, primarily on suspension components, but you won’t find many cadmium plated components on GM and Chrysler vehicles. They preferred the black oxide coating you see on their bolts and other components. Door latches were commonly constructed of GALVANIZED steel.
As to why you found metallic red paint under the original gold paint is a head scratcher. Most likely there was a problem in the paint delivery system about the time your car rolled into the spray booth and a little red sprayed out before the gold reached the NOZZLE.
This is beginning to sound like a subject that needs further exploration. Watch for an article. I’ll see what I can do.
Can I Wait a Year to Color Sand?
I have all of your DVDs and have read all of your articles in Auto Restorer,as well as the book,“ Project Charger.” Great stuff!
I’ve painted a few tractors using single-stage paint but would really like to paint my T/A Challenger using a base coat/clear coat finish. However, my schedule is such that I will need to paint the car and let it sit for about a year before color sanding and compounding. Is there a maximum time that can go by before the clear coat is color sanded and compounded? I’ve been told the sooner the finish is sanded and polished the better. Will I run into any issues if I let the finish sit for a while?
Phil Narjes Lodgepole, Nebraska
Glad the DVDs, articles and “Project Charger” have helped.
To answer your question about delaying color sanding and compounding, you can wait as long as you desire without doing any harm to the finish. The reason you hear“ the sooner the better” is because fresh clear coats are easier to sand and polish than are clear coats that have cured for a year. Time is money in the body shop world so delaying means more time spent and higher labor cost.
When you are ready to color sand and compound, start by wet sanding the car with 1000-grit, then 1500-grit, and finish with 3000-grit. That will give you a nice surface and reduce your time behind the buffer.
Two Sources for Quarter Panels
Thanks for the great Mustang article in the March issue (“Quarter Panel Replacement”). Could you suggest a source for the replacement quarter panels you used?
John Forsyth Shelby Twp., Michigan
I’ll give you two. The first one is National Parts Depot (npd.dirxion.com) and the second one is California Mustang (cal-mustang.com). I’ve used both of these companies on pastprojects and like both the quality of the products and the service provided.
I should add that no matter where you choose to purchase replacement Mustang quarter panels, it is my opinion that purchasing OEM-style panels will net you far better quality and fit than purchasing an outer skin like the one I used on the left side of the Mustang in the article.
Help Me Remove My Brazed Panels
Several years ago I replaced both quarter panels on my 1968 Dodge Dart using brazing to attach them. I want to restore the car back to original now but I’m not sure how to go about replacing the panels that were brazed on. Any suggestions?
Chris Patrignani Via email
It is very difficult to remove a panel that has been BRAZED. About all you can do is heat the brass enough to break the joints and remove the old panels. Once you have done that you will need to heat what is left of the brass and brush it with a wire brush to remove as much of it as you can. The brass will melt before the steel melts so you should be able to remove most of it.
It is going to take a lot of work to remove the brass and get the metal clean enough to weld but it can be done. The amount of heat it will take to melt the brass will cause some warping but since you are going back with new quarter panels any warping that does occur should be easy to deal with. I would also try to position my new spot welds to avoid any areas of brass that couldn’t be removed.
Is Epoxy a “Weld-Through” Primer?
In your article on quarter panel replacement in the March issue you stated that you finished up by applying epoxy to everything hidden beneath the quarter panel. You then went on to state that the application of epoxy will accomplish two things.
First, it gives the car some much needed rust protection and second, it serves as a “weld-through” primer.
Do you know something new about epoxy primers? I use a zinc-based weld through primer for this purpose. As far as I know epoxy primers will burn away long before they reach welding temperatures leaving behind flakes and carbon deposits. If there is such an epoxy primer I would like to know about it.
Jim Mills Via email
I learned about the use of epoxy primer as a “weld-through” primer through ICAR, Inter-Industry Conference on Auto Collision Repair. They suggested using a catALYZED epoxy primer as a “weld-through” primer because it will hold up under the heat of welding (spot welding) as well as ZINC-RICH primers and it can be applied over painted, primed or GALVANIZED surfaces. Weld-through primers cannot. These primers must be applied to bare mild steel only. Epoxy also offers improved adhesion for anything applied over it whereas ZINCrich weld-through primers have such poor adhesion it is recommended that any excess ZINC-RICH weld-through primer be removed from any exposed areas that are to be later refinished.
That said I have nothing against the use of ZINC-RICH weld-through primers. They work great and I would not hesitate to use them.
That Was a Robertson Bolt
I read with interest the automotive bolt article in the February issue. You mentioned most of the bolts in use on automobiles but you failed to list the name of the bolt that requires the square drive socket you mentioned. That bolt is a Robertson and was used extensively on the 1926 Ford Model T that was made in Canada. Thanks for allowing me to, as you always say, “send it along.”
Don Cunningham Ceres, California
And thank you for the information.
Don’t Patch Those Holes With Body Filler
I have a 1980 Camaro that has some rusty areas in the lower front of the quarter panels. There is some minor perforation but it is not severe. I would like to fix this right, but I think replacing the quarter panels is beyond my skill set. Eastwood makes an internal frame coating that I am thinking of spraying inside the quarters to stop the rust then fill the small holes with plastic body filler. Does this sound like a reasonable approach?
Don Swanson Chesapeake, Virginia
The Eastwood product you mentioned is Internal Frame Coating #12515Z. This product contains ZINC phosphate which makes it a pretty good rust stopper
However, I would lean more toward Eastwood Rust Converter #51483Z as it has the capability of reaching into the tight areas of the quarter panels where it can react with any active rust itfinds.
I would also for go the use of plastic body filler to fill the small rust holes. Instead, I would use 3M 8115 Structural Adhesive. Follow the directions for application. Once this product has cured you can sand it smooth and apply body filler over it if necessary before priming and painting
The problem with using body filler to fill rust holes that bodyfillerwillwickup any moisture that gets into the area and greatly shorten the lifespan of the repair. Using 3M 8115, which is epoxy based, with give you a moisture-tightrepairthat should last for many years.
Why Not Use a Base Coat/ Clear Coat Finish?
I am restoring a 1965 Corvette to NCRS (National Corvette Restorers Society) Top Flight standards. Although in a perfect restoration we would use the original acrylic lacquer paint, I am reluctant to use this material because it will eventually become brittle and crack.
Is there a new formulation for this paint that is more resistant to cracking and checking?
If I use acrylic enamel instead, what products or techniques would you recommend to closely match the appearance of the original acrylic lacquer?
Robert Mann Los Angeles,California
I have had some experience with the NCRS standards where paint is concerned. I sprayed a 1967 Corvette Code 976 Marina Blue and used PPG base coat/clear coat to refinish the car. The owner informed the NCRS judges of the type of paint used and the only points deducted from the paint aspect of the car was for a chip at the bottom of the driver’s door caused by a rogue seat belt on the day of the event.
As for why the owner elected to go with the base coat/clear coat finish, the primary reason had to do with the longevity of the finish. Like you, he didn’t want a finish that would need to be replaced a few years down the road. That finish, of course, would have been lacquer, which hasn’t been improved upon since the transformation into acrylic lacquer. Like the old stuff, acrylic lacquer will still check and crack. All it needs is time.
My reasons for using a base coat/clear finish was first, the finish would require some color sanding and buffing, and second, I wanted the finish to be durable. Because this was a metallic finish, using enamel was out. If you color sand and buff a metallic finish that was sprayed in enamel you run the risk of producing a finish that is mottled because the process of color sanding exposes the metallic sand can change the appearance of the finish.
Spraying a base coat/clear coat finish eliminates the possibility of mottling because what you are color sanding and buffing is the clear coat and not the metallic color coats underneath.
You didn’t say what color your Corvette is going to be sprayed, but if the finish is a metallic I would strongly urge you to use a base coat/clear coat finish.
If the finish is non-metallic, such as a black or red, you can use enamel with a hardener or a single-stage urethane to refinish the car. Apply at least five coats then color sand and buff the finish using 1000-grit, 1500-grit then 3000-grit sandpaper before compounding the finish to a very nice shine.
Advice on Removing a Protective Oil Coating
In response to James White’s question (February) regarding removing protective oil from a car body after it has been dipped to remove paint and rust; I would offer the following solution.
Hold Tight 102 is a terrific after-wash for most blasting applications and may be a good application for James’ situation. It is a surfactant (reduces surface tension) and when used correctly, will leave a contaminant-free surface with no residue to interfere with coating adhesion. HoldTight 102 is somewhat like soap, but unlike soap, it will not leave a residue when dry.
It also offers a three- to five-day window to get the body in primer.
Stacy Stone Chesapeake Soda Clean, Inc. Millersville, Maryland
Thanks, Stacy. Your help and expertise is always welcome. I would suggest calling Chesapeake Soda Clean, Inc. at or visiting their web site at www.chesapeakesodaclean.com to get more information on HoldTight 102 and forproduct ordering information.
Generally, I Wear a Respirator
Everything I have been told about spraying base coats and clear coats is that one should wear a respirator with a fresh air supply. In your DVD, “Painting Techniques, Stage II,” it appears this is not the case. Correct?
Bill Eggener Via email
The mask I wore in that DVD series is a 3M Half Face Respirator#7082. This unit is rated for spraying both base colors and clear coats so it is a very safeway to go. I prefer wearing a fresh air system when spraying large projects, like the carI refinished in the DVD, but due to the number of electrical cords we have to route around the shop during filming I have found it far simpler to forgo the fresh air system. Something I should add is that when not filming I also wear a respirator any time I mix paint.
Editor’s note: For more on Larry’s series of how-to DVDs,visit his Website, lplbodyworks.com.