The assembly of Octavius has started simultaneously from various locations. Although there are many works being carried out at the same time, not all groups have been completed. Group 60: Shell, Grommet is the first group to be officially completed.
Dry ice blasting has been introduced to our shop, which doesn’t make the job easier, but it makes sense to restore everything on the bottom. I live in a high-dust area, nearly the whole China is high-dust. Past repair experience is that we redo everything, but before we finish the installation all the parts are covered with new dust, they are repaired more psychologically, not visually. And even if I choose the traffic conditions very carefully, we still inevitably get the underside of the car dirty. For example, when encountering a sprinkler on a ramp, I can’t brake suddenly or turn around, I can only slow down, and the muddy water will still roll to the bottom of the car. Dry ice cleaning can remove surface stains, which will maintain the bottom of the reconstruction, making cleaning not a one-off. So although shell maintenance is very complicated, I don’t want to miss this opportunity to make it clean forever.
Dry ice blasting is considered a thrill job, but a complete restoration is not as simple as Youtube detailing. While all the parts were still there, I did the first stage cleanup. After everything has been removed, do the cleanup again and again. This is very time-consuming work, because there are a lot of stains covered by the bottom parts. If you compare it with detail cleaning, the workload is about 10 times. This process consumes more than 100kg of dry ice. If the shaded area is recontaminated in the future, dry ice blasting won’t help, so still drive with caution. Some of the paint (corrosion) will also come off during dry ice cleaning, especially over the rear axle, where there isn’t any extra protection. Not really surprised, since Octavius lived in a humid area for his first 18 years, what can we expect?
The first focus of the work was the floor above the rear axle, as planned we would install the rear axle first and then move on to the bodywork not covered by the rear axle. Group 98: Paint in WIS has 4 documents describing how the car body was treated for corrosion protection at the factory. They are not helpful in recreating factory technology because there are no such facilities (electrophoresis and super high temperature). They also aren’t much help in guiding restorations, as production doesn’t strictly follow these documents (painted areas tend to be relatively haphazard). What these documents can do is effectively identify what the different colored coatings on the body of the car represent.
- The grey electophoretic coat. They are the base coat of the entire body. Tactile and visual characters are similar to base paint.
- Seam sealing. They fill the gaps betwwen panels. If there is no other coat over it, they are ivory yellow. If there are, they painted in the overcoat color.
- Underbody protection. They are limited applied to certain area of the body with two different thickness. It’s over the electophoretic coat.
- Rust preventer wax. They are yellow-white wax sprayed to certain areas. It’s over body electophoretic coat and suspension parts.
While I’m after factory spec, #4 rust preventer wax is an ugly option. Not only does it affect the aesthetics of the bottom, it is also very difficult to remove. So I decided to remove this coating permanently.
#1 Electophoretic coat
Start with fixing the E-coat. During the dry ice cleaning process, there were many spalled areas above the rear axle that injured by the dry ice. Immediately after the coat peeled off, the red rust spots appeared, they were there long ago, the half peeled coat was just blown away. Fortunately, these are only superficial rust spots. Octavius mainly lived in Hangzhou, where there is no snow for the first 18 years, which is rather important.
As I mentioned, factory techniques are beyond the reach of independent shops, so bodywork restoration must retain as much original craftsmanship as possible. This means I don’t completely remove any one coat and remake it, the factory techniques are very corrosion resistant and they will continue to function for the next 100 years. For the electrophoretic coat at the very bottom, I would only repair the peeled part, which is already a lot. Restoration is a subjective art. My understanding is to achieve the same visual and performance, but the technology will be different.
First I sanded off the rust, and promptly applied PPG marine primer, which is an absolute overkill for car repairs. 9 years ago we repaired the shell of a classic Chinese car and painted it with this paint, then it was placed in the yard in the open air. This kind of car did not have proper anti-rust treatment when it was shipped from the factory, and it often had a large area of rot, but the repaired and sprayed car shell has no visible rust. Yes, 9 years have passed, and it is 20 kilometers away from the sea.
The primer itself is a close to E-coat gray, but that’s not enough, and it has a rough finish. I decided to re-cover the repaired area with a consistent color paint. In order to prevent color difference in the future, I sanded the whole part and will spray the complete area. There are many challenges in the preparation work, if painting the body is the process of making mirrors, repairing the bottom is like an adventure in the ocean, you will make many new friends. For example, the Seam sealing will be connected with the E-coat, in order to maintain the factory appearance, it is better not to paint the yellow seam sealing. But following the track of the sealant, you will find that some sealants are covered by gray-green anticoression PVC coat, so you need to consider how to find the boundary between E-coat and PVC coat, which are two different colors.
I took pictures after the dry ice cleaning and before repairing the E-coat, it was helpful to find the corresponding color of each area. But Octavius itself is not an ideal example and needs a better reference. I found a bottom photo of a 1994 S 600 on Bring A Trailer, 1994 is the rarest Model Year for an S 600 in the US market. The car has 58k miles on it and has a pristine bottom. Its VIN is A150421, Octavius is A149549, I think close enough.
Working in the rugged ocean is much more difficult than working on mirrors, and believing that there are no shortcuts is the only shortcut. I’m going to cover up the yellow seam sealing with masking tape, they are very irregularly shaped and I must admit I can’t keep 100% of the original shape, but over 90%. There are also rust preventer waxes that cannot be easily removed in many places, and need to be slowly removed with a blade. The original E-coat is so smooth it’s like paint, so it’s not too much of a stretch to use paint to replicate its look. Of course, this gloss is between gloss and matt. In order to achieve this gloss, we tried adding different proportions of matting agents. Spraying is carried out using a spray gun, and only in this way can the surface be smoothed.
How to control the boundary with PVC coat? This is a later issue as the E-coat is at the very bottom and the over spray can be corrected later with the color of the PVC coat, the most important thing now is just to make sure the yellow seam sealing doesn’t get over sprayed.
After the major E-coat damage above rear axle is done, I moved back to other section in the front. The underside of the firewall is corroded by coolant, it looks like a user in southern China used water as a coolant, and the coolant pipes corroded and leaked onto the front side members. The rust was deep and the position is difficult to sand down by hand or machine, so I used oxalic acid to kill 80% the corrosion, then immediately applied PPG Marine Primer.
#2 Seam sealing
The seam sealing is relatively easy to work with and their durability is much higher than E-coat. Of course, this step cannot be skipped, there are two types of work that needs to be done. First was the damage near the firewall that was just done, the sealant damaged due to prolonged coolant & water soaking leaked from the coolant pipe. Plus the location is also under the brake booster and ASR pump, the brake fluid credits too. There are some sealant that don’t come off completely, but they can be easily removed.
I removed all removable sealant, actually this step was done when repairing the E-coat, now need to apply the new sealant. I used Wurth’s Structural adhesive PU, which is white, but it doesn’t matter as the black paint will cover it.
#3 Underbody protection
The high abrasion-resistant PVC substrate coat is a difficult point, and these gray-green coats appear in irregular forms. Although the documents given by WIS express the standard operating area, the pattern on the actual car has obvious traces of artificial spraying, even over spray. For example between two areas that don’t touch there will be a coat belt that connects them, well I guess the operator is releasing the switch when moving the spary gun.
What we are facing here is an epistemological choice. Should we completely copy the pattern of the original car or make the pattern according to the production documents? Let’s see the results of both ways. The current pattern itself is arguably ugly, especially under the trunk, which thankfully will actually be obscured by the exhaust pipes. If the patterns are remade according to the production files, the bottom will look nicer.
Restoration is always a subjective art. At present, I don’t know any workers in this position, and I don’t know what happened that year. But I don’t think it’s too much to make some aesthetic improvements in line with production spes. I’m going to take a similar method, that is, without using any masking tape to create a “hard border”, but let the two coats meet naturally.
The reproduce patterns are mostly about the spectrum, as I said, the original coat is not removed, they will served as they used to be. In some areas there is damage caused by scratches, I used the previous structural adhesive to fill in with a brush. Next I was going to preview how to paint the color according to WIS’s guidelines, for potential future tinkering I used the relatively generic RAL 7022, (due to fading, it is difficult to guarantee the same as the original here). Yes, it’s just paint, they will bring back the aged color, but don’t have the abrasion resistance of PVC coat by itself, I have to be careful with future use.
I would start by spray painting the area covered by the piping and exhaust and stop. Here is our first tactic, due to the there is no space to remove the seats and floormats on a two post lifts (even if we did before lift him, there is no clearance to climb into it), the necessary sheet metal work from upside has to be carried out after the car off the lift. Ocatavius will have axles and almost everything installed then, the floor sections above piping is what we need to do in this stage. Correspondingly, most of these sections are well-protected from axles and exhausts, so we don’t really need any further sheet metal work. Overall I am very happy with the work, the important thing is that the imperfect original traces are not covered up.
#4 Surface paint
As previously discussed, the anti-corrosion wax is not reintroduced, instead repairing the damaged black paint. Overall, the black paint has a very limited presence on the underside, but it’s all over the engine bay. During production, the paint in the engine bay is not covered with a clear coat, they are not resistant to abrasion or oil. From past use and cleaning, much of the paint wears off and reveals a gray E-coat, even scuffed by the wiring harness. Around the ASR pump and brake booster, the brake fluid also took the tint out of the lower paintwork.
Repainting will replicate the same texture, you could say it’s semi-gloss or close to matt. I don’t want the engine bay to be shiny, that would be over-restored. Prep for this job is very important as over the last 30 years the engine bay has accumulated all sorts of fluids which if not cleaned off completely will cause the paint not to adhere, I did a degrease job and dry ice blasting here again.
The pattern of the black paint is also irregular. Some of these colors are splashed by the robot when it is sprayed from the side, and some are splashed by the workers when they spray the engine bay. The latter has great uncertainty. So still following the methodology of imitating the underbody protection pattern, I didn’t do any masking on the border, but repainted along the track of the old paint.
The last job before painting is to inspect the grommets, the vast majority of them should not be painted and therefore require additional masking. Here since some of the grommets near the engine and exhaust had hardened, I ordered new ones, the old ones were used to block the paint and they were at the end of their life. I didn’t replace all the grommets, actually some are under PVC underbody protection, there is no need to destroy them.
The body is now ready. Next we can install the hydraulic lines and rear axle.