An In Depth Outline

by Tyler Krause July 07, 2022

This outline dives a little deeper into all of the steps. While each step still isn't broken down very in depth, it might be a good resource for some more basic and helpful information in one place. Warning, it's a lot of steps.

These steps are assuming the vehicle has already been stripped to bare metal, and all necessary fabrication has been completed, and it’s ready to begin the body work process.

Vehicle sitting on its suspension, and level. Preferably on the wheels on tires. Just as it will when completed.
If applicable, all body mounts torqued evenly. A torque wrench can be used for this.
All body panels bolted in place, with all necessary hardware. Don’t skip any bolts that ‘aren’t needed’, use all hardware, just as it will be when completed.
All weatherstrip, seals and rubber bumpers in place.
Body panels adjusted as good as possible
Using as long of an aluminum c-channel or flat stock as possible, spanning multiple panels (if possible), check for: where panel edges are (the edges should be touching the aluminum), high spots, low areas.
These aluminum pieces are a preview to where the body work will end up being.
Make any necessary changes based on what the aluminum c-channel shows. Almost always, the panel edges need to be moved out to touch the aluminum, so they remain thin after body work. Sometimes this can be done with only hammer and dollying the door or fender edges. Sometimes cutting and welding is required.
After edges are flush according to the long c-channel, not a 12” ruler, the gap width needs to be set. The gaps will open up if the panel edges move out.
Normally what determines the gap size is how much clearance is needed for the doors to open. Set this gap first, and then make the rest of the gaps match.
If a gap is too tight, grind the panel edge back until it’s large enough. If welding is required, its recommended to grind the gap slightly larger than needed. Then TIG weld the panel edge. With the gap being slightly larger, there will be a little extra weld on the panel edge, giving more material to file if necessary.
Make sure all the panel edges are filed straight, and are a nice consistent shape. Make the gaps as nice as possible.
Use a digital caliper to check the gap sizes. Make sure the caliper is as far in the gap as possible, and square. Not just barely in the gap. The entire gap needs to be the correct size.
Prep for epoxy or body work begins. Both require the same: obsessive attention to every detail.
Cleaning is first. Wipe the metal down very good with a non-acidic metal clean, such as Glasurit 360-4. Lacquer thinner can also be used in this initial cleaning. The point is to remove any oils, permanent markers or layout dye.
Then clean the metal good with pure, 99% isopropyl alcohol. This will remove any water based contaminants from the metal, like finger prints.
Follow the alcohol with a solvent based wax and grease remover. The same cleaner that would be used in the paint prep process.
The metal must be absolutely spotless. Any void in any weld, no matter how tiny, must be cleaned and completely white all the way to the bottom of it. This almost always requires media blasting, and checking with plenty of light. Rust pits are treated exactly the same. The bottom of every single rust pit must be media blasted completely clean.
Typically, a fine or medium glass bead works very good for media blasting. Consult a professional with media blasting for the exact recommendation.
Sometimes, all the metal might be media blasted. Sometimes only some areas may require it.
After media blasting, sand the metal very good with a D/A sander and sharp 80 grit. It’s wise to leave inside corners in a blasted finish, as epoxy will adhere better to that surface than a sanded surface. This is because the sandpaper isn’t as effective in tight corners.
Clean the metal again very good with the non acidic metal cleaner. The cleaner should be sprayed on the surface, and then wiped dry. Clean/new microfiber towels work well for this. Keep cleaning the metal until it’s wiped off, and the towels remain clean.
Follow the metal cleaner with the solvent wax and grease remover.
Apply a high quality epoxy primer.
Let epoxy cure for at least several days, preferably a week or more. It must be cured before any body filler goes on top of it.
If the body was disassembled for epoxy, re assemble and adjust all panels. All hardware must be used again.
Prep the epoxy for body filler by sanding it with 100 or 120 grit. It should be sanded thoroughly. Body filler will not adhere to unsanded cured epoxy. So, make sure there isn’t one spot missed. It’s a good idea to scuff the epoxy with a red scuff pad first, to help ensure the whole surface is at least thoroughly scuffed. Sanding with 100 or 120 follows the scuff pad.
Blow the epoxy off good with a blow gun. Clean with wax and grease remover, so the body filler goes on as clean of epoxy as possible.
Being body work. Use the same aluminum c-channel or flat stock from earlier steps to help guide where the begin applying the body filler.
Come up with a plan for the body filler. Don’t just start spreading filler. Try to figure out which section should be done first, that will help establish a section that can be worked off of. Usually, beginning with the center of the car is the best, since that’s usually the peak of the crown or shape of the sides.
Look at the vehicle as one whole shape. Ignore where the body panels are, rather see it as sections of shapes with panel gaps cut into those shapes. Your goal is to make those shapes as consistent and ‘straight’ as possible.
Usually, moving panels, such as doors, decklids and hoods, are slightly higher than their adjacent panels. Because of this, it makes much more sense to begin body work on those moving panels, rather than the panel that’s lower. If you body worked the quarter panel first, and then went to the door, you’ll end up re-doing the quarter panel to make it match the door. These are slight differences, but the goal is perfection, and everything to be exact.
A reminder, that using the long (6 to 8 feet long) pieces of aluminum are the key to predicting where the body work will be, where the panels need to be, and where to begin. There should be few surprises if these are used.
Body work one section at a time. The overall body work is better and more efficient if it’s done one section (not panel) at a time. With a section established and straight, it makes it better to build off of that. If you have multiple sections just started and not quite straight, it’s too much back and forth, and you don’t know what’s actually straight. So, get a section straight, and then move onto the next section, using the first section as a reference and something to build off of.
Use 80 grit to sand the body filler. Sand the filler before it’s completely dry. It should be a little bit tacky yet. There is a perfect time before the filler is completely dry, but after it loads the sandpaper up too much.
Continuously use the aluminum pieces to check the body work, know where to fill and know where to block sand.
Before spreading more filler over previous filler, all of the filler must be sanded. Often times there are voids of unhanded filler. Be sure to sand those before spreading more filler on top.
Get all of the body work done on the body, everything needs to be as straight as possible.
Thew body lines needs to be taped and sanded straight. They should be made somewhat straight during the body work process. But now is when then are made completely straight.
Prep all of the door and panel gaps for body work
Gap all of the panels, using the plastic gapping tools
Block sand the entire body with 120 grit, so all of the 80 grit is completely gone.
Blow off body filler very good with a blow gun and clean/dry air.
Fill all pin holes and other small details with body filler. Let dry.
Block sand the filler from the pin holes, being careful not to over sand the area around this filler.
Blow out filler very good, and blow the vehicle out, to prep for primer.
Clean with solvent wax and grease remover
Mask vehicle for polyester primer. Typically, masking at the first corner in the jambs works well, so that overspray mostly stays out of the jambs, but isn’t a hard line right at the gaps.
By hand, sand any bare metal with sharp 80 grit. Be careful not to sand the filler next to it. A block can be used as well. This is just to ensure there are sharp scratches in the metal for adhesion purposes. Clean these spots with wax and grease remover.
Metal spots that are larger, approximately 1” or more, should be epoxied. All metal spots can be though.
ONLY dust epoxy on. You should be able to see through the epoxy. It should be dry as soon as it’s on the metal. This is extremely important. If it’s not dusted on like this, the polyester will come off of it.
Let these epoxy spots dry for several hours (or longer). Lightly scuff them with a red scotch brite pad, and then lightly sand by hand with around 150 grit. Polyester will not adhere to unhanded epoxy.
Polyester primer the whole vehicle.
Put several small dabs of body filler in each of the panel gaps, to make sure you can block sand across the panels, and nothing moves are all. This keeps everything as flush as possible.
Block sand the polyester primer with 100 grit and the same blocks from body work.
Make sure the polyester is completely flat, with not organs peel remaining, and everything is completely straight.
Blow vehicle off, and clean with solvent wax and grease remover, to make sure all dust is off of the polyester primer.
Apply dry guide coat thoroughly. The guide coat needs to be absolutely everywhere. Literally not one scratch can be missed with the guide coat.
Block sand, with the same blocks, with 220 grit.
After blocking, blow the primer off, and then wet it down with wax and grease remover, this makes left over scratches show up.
With a pencil, circle and scratches remaining
Further sand the circled areas to finish removing the scratches.
After all scratches are gone, blow body off, and clean again with wax and grease remover.
Apply dry guide coat again, just as thoroughly
Sand the primer with 400 grit and a softer block, like a foam block. “Soft Sanders’ by the Style Line company is a good example of a block to use. It’s a similar material to a pool noodle.
After sanding, wet the primer down with solvent wax and grease remover and circle any missed areas. Once dry, go back and sand those areas more.
Disassemble the body, and body work whatever is required in the jambs, including ‘back filling’ where the gaps were done.
Polyester prime the jambs.
To sand the primer in the jambs, ideally it should be done with the same steps as the outside. It is possible to cut some time, and do something like 150 and 320.
Once the jambs are sanded, the vehicle is essentially ready for the painting process. The final thing to do is go over all of the primer with something slightly softer and finer.
One option is the 3M Soft Back Sanding Sponges, using the ‘Super Fine’ grit. Or, use the velcro cloth sandpaper. That is available with several brands, and is usually perforated and tears in half. This is available in 500-600 grit.
Use either of these sanding options, on a block like a wet sanding sponge, so no grooves are made. No guide coat is needed, but this will help soften everything up a little more, and make it a little finer than 400 grit.
Sealer must be used over polyester primer. Base coat cannot go directly on the polyester. It is optional if the sealer is wet sanded before base coat. It does not need to be, nor does it make a big difference in the final result.
For painting, most colors should be painted with the body together to ensure an exact color match from panel to panel. Yes, it’s very possible to paint apart and have the colors match. But, it is rare it’s as perfect as if it was actually painted together. The point of all this is to be exceptional, not ‘it should be fine’. Painting apart is also a big gamble, and the first time you’ll find out if it matches, is after all the wet sanding and buffing is done and the body is being assembled. That is a whole lot of wasted time and money if it doesn’t match. It’s a large gamble when the solution is not much extra work.
To begin, the vehicle can be sealed with all panels completely apart. The base coat can also be done like this, making sure there is full coverage in all the jambs. At this point, the vehicle’s panels are all disassembled, and the panels are all in base coat, with the focus being on the jambs being fully covered. The outside is also painted.
Being very careful, not touching the basecoat on the outside, with gloves on, and allowing as long as possible, preferably a minimum of 4 or 5 hours after the base coat is sprayed, the body gets very loosely assembled. This assembly is just enough so the panels can be next to each other. This could mean that the front of the fenders, for example, are held up be panel stands, and 6 to 12” in front of the door.
Once the body is very loosely assembled preferably two or more coats of base coat is sprayed on the outside, walking the length of the vehicle. This makes sure all the panels are being sprayed next to each other and exactly the same. Enough base coat needs to be sprayed so that if there was a color difference, it can be hidden and doesn’t still show through.
This base coat also needs to dry for at least several hours. Then very carefully taken back apart, with gloves on, and absolutely not touching the base coat on the exterior. There is no room for error here.
Once all the panels are back apart, it’s time for clear coat. It’s best to clear the vehicle in batches, since there’s usually not enough time to get around all the panels within the flash times.
For clear coat, typically 5 or 6 coats are required. These coats are to be medium coats. It is very okay, and recommended to have the clear coat have some orange peel. It’s going to be sanded flat, you do not want the clear moving or flowing out.
Flash times are crucial. Do not go by how much time has actually passed. Go by how dry the clear actually is, by touching some tape somewhere, or a flange that isn’t seen. Do this somewhere near where you started spraying. Some clear coats still need to be stringy when the next coat is sprayed, and some clear coats need to be slightly drier and just tacky when the next coat is sprayed. The flash times will get longer after each coat is sprayed.
Medium, not heavy coats, and flash times are the two very important parts of clear coat.
Let the clear coat air dry, do not force dry it. Let the booth continue to run, so the airflow never changes. Even if this means running over night, or at least for a few hours after the clear is done. Baking it may cause solvent pop, it’s by far the best to just let it dry on it’s own.
The wet sanding can begin after the clear coat is dry. The longer the better, but reality doesn’t always allow that. A day later it can be sanded, although it’s still soft. It can be baked the next day, before and after the initial sanding step. It works well to bake it after every wet sanding step. The more heat the paint can see, the better.
Wet sanding step one is to sand the clear coat completely flat. Do not move on until it’s completely flat. The first step is 600 grit and a hard wet sanding block, like the True Blox wet sanding blocks. It can, and usually should be, flexible, but it needs to be a hard surface.
After each of the sanding steps, the paint is to get cleaned the same way, using water borne cleaner to remove all sanding residue. This is so the guide coat is able to get in all scratches. Mirka dry guide coat works well. There is black and white. Use black whenever possible, even if it seems slightly harder to see. The white doesn’t work nearly as good, so don’t use the white unless you just can’t see the black guide coat when sanding.
1,000 grit is next, with the same sanding block that was used for 600 grit.
Clean and guide coat
1,500 grit with a traditional foam/soft wet sanding block, such as the Motorguard blocks.
Clean and guide coat.
2,000 grit and the same softer block
Clean and guide coat
2,500 grit with the same softer block
Optional 3,000 grit, not tri-zact sandpaper. Tri-zact pads barely do anything, they just make the paint shinier. The point of any steps beyond 2,500 grit would be to help reduce the slight grain that’s left in the clear coat. Tri-zacts don’t help this grain. A good sandpaper, like Starke Matador, has 3,000 grit. Use something quality like this.
For 2,500 or 3,000 grit, it’s imperative to change the sandpaper a lot, even before it’s dull. Clear coat gets built up very easily in these very fine grits, and will leave scratches in the paint, and you won’t even know its happening.
Buff with a high quality wool pad and heavy compound at a low speed, under 900 rpm’s, at most. The first buffing step is to completely eliminate the slight grain look in the clear coat, and to remove any and all scratches. Other than swirls, the paint should look perfect before moving on from the wool buffing pad.
Clean the paint with a water borne cleaner to remove all compound.
Buff, at the same low speed, with a medium cut foam pad and medium compound. This step will remove the swirls from the wool, and help get anything else dialed in and gone.
Clean with water borne cleaner
Final Polish with a fine foam pad and high quality polish